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Length: 12032 (0x2f00)
Types: RcTekst
Names: »44RT2119.WP«
└─⟦d6fd29e8c⟧ Bits:30005864 Manualer - tekstfiler 42-I og 44-RT afdelingerne
└─⟦this⟧ »44RT2119.WP«
╱04002d4e0a00060000000003013c3140000000000000000000000000000000000000000000000000050f19232d37414b555f69737d8791ff04╱
┆b0┆┆a1┆┆f0┆┆e1┆┆06┆i↲
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┆b0┆┆a1┆TABLE OF CONTENTS┆05┆PAGE↲
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1. DESCRIPTION ........................................ 1↲
1.1 Hardware Survey ............................... 4↲
↲
2. THE KEYBOARD CONTROLLER (KBC751/KBC752) ............┆05┆6↲
2.1 Logic Diagrams and Functional Description .....┆05┆8↲
2.2 Special Hardware Features .....................┆05┆11↲
↲
3. THE KEY SWITCH ASSEMBLY (KSA751) ................... 16↲
3.1 The Phantom Phenomenon ........................ 16↲
↲
4. THE MICROPROGRAM ...................................┆05┆19↲
4.1 Error-Codes ...................................┆05┆19↲
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┆14┆┆b3┆┆a1┆┆b0┆┆e1┆┆06┆┆0b┆↲
┆b0┆┆a1┆1. DESCRIPTION↲
↲
The RC730 is the keyboard for the RC750 microcomputer. The ↓
keyboard is based on the position-code principle. I.e. that ↓
a depression of a key results in the transmission of a ↓
position code. Therefore the host computer must perform a ↓
translation from position codes to e.g. ASCII. When a key is ↓
released, 128 (decimal) is added to the position code and ↓
this code is then to be transmitted. I.e. that a single ↓
"hit" on a key results in the transmission of 2 codes. The ↓
position code allocation is shown in fig. 1.2.↲
↲
The position codes is transmitted to the host in a serial ↓
form. The keyboard provides both data and clock information.↲
↲
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┆06┆Figure 1.1: Keyboard layout.↲
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┆06┆Figure 1.2: Positioncode allocation.↲
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┆b0┆┆a1┆1.1 Hardware Survey↲
↲
The RC730 keyboard consists fo two modules: KBC751/KBC752 ↓
and KSA751.↲
↲
KBC751 is the controller module and KSA751 is simply the PCB ↓
where the keyswitches are mounted.↲
↲
The controller performs the "reading" of the switches, the ↓
transmission of position codes and the generation of ↓
"keyswitchclicks". The controller has also got a connector ↓
which is intended to be used in conjunction with a mouse. ↓
Fig. 1.3 shows the physical interconnection of the modules.↲
↲
The connection to the computer is made through the cable ↓
KBL574. The definition of the cable is as follows:↲
↲
┆06┆ Pin 1: Strobe Clock from keyboard↲
2: Serial Data from keyboard↲
3: no connection↲
4: 0 V↲
Front view 5: 6,5 V - 7,5 V supply↲
5P DIN-connector Shield connected to housing↲
(DIN 41524)↲
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┆06┆Figure 1.3:↲
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┆b0┆┆a1┆2. THE KEYBOARD CONTROLLER (KBC751/KBC752)↲
↲
The KBC751/KBC752 is based upon a 8039 single chip micro- ↓
computer. The program for the microcomputer is stored in 2 K ↓
x 8 ROM (2716). ↲
↲
In this section the hardware around the microcomputer will ↓
be described. The KBC751/KBC752 assembly drawing is shown in ↓
fig. 2.1.↲
↲
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┆06┆Figure 3:↲
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┆b0┆┆a1┆2.1 Logic Diagrams and Functional Description↲
↲
┆a1┆Signal┆e1┆┆06┆┆a1┆Description↲
↲
MOUSECON╞ ╞ Serial data input from mouse.↲
RX╞ ╞ ╞ Returnline for the two SHIFT-keys.↲
R0-7╞ ╞ Returnlines from the KSA751↲
T0, T1╞ ╞ Input from nationality switch↲
DA0-7 ╞ ╞ Data-Address bus.↲
LATCH╞ ╞ ┆84┆Strobe signal present in the mouse ↓
┆19┆┆99┆┄┄connector J3.↲
ALE╞ ╞ ╞ Address latch enable↲
PSEN╞ ╞ Program store enable↲
A8-A10╞ ╞ 3 most significant address bits.↲
DATA╞ ╞ Unbuffered DATAOUT-line↲
CLOCK╞ ╞ Unbuffered inverted CLOCKOUT line↲
CLICK╞ ╞ ┆84┆Controls the activation of the ↓
┆19┆┆99┆┄┄relay↲
┆a1┆┆05┆↲
↲
S0-12 ╞ ╞ Scanlines used on the KSA751↲
SX1, 2╞ ╞ ┆84┆Scanlines dedicated to the ↓
┆19┆┆99┆┄┄nationality switch and the two ↓
┆19┆┆99┆┄┄SHIFT-keys.↲
DATAOUT╞ ╞ Serial data from keyboard.↲
CLOCKOUT╞ ╞ Strobe clock from keyboard.↲
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┆b0┆┆a1┆2.2 Special Hardware Features↲
↲
┆a1┆The keyboard scanning↲
↲
The scanning circuit consist of the 4 IC's 1, 2, 3 and 4. ↓
The IC4 is a 4-to-16 line demultiplexer. The IC's 1, 2 and 3 ↓
form a line of 18 inverters with open collector outputs. ↓
One, and only one, of the scanlines S0-S12 and SX1, 2 will ↓
be pulled low at a time. The rest of the scanlines will be ↓
in the high impedance state. The line to be pulled low is ↓
selected by the 4 selectlines A-D on IC4.↲
↲
The selectlines A-D is connected to the addresslines A4-A7.↲
↲
The STROBE-input on IC4 is connected to the most significant ↓
addressbit, A10. The following figure will describe the ↓
scanline addressing.↲
↲
┆a1┆MSB ENABLES SCANNING LSB↲
┆a1┆ A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 ┆e1┆ BIN↲
┆a1┆ H2 H1 H0 ┆e1┆ HEX↲
CONTROLS DON'T↲
┆a1┆ SCANLINES CARES ↲
↲
Example: ┆84┆In the address 043B(H) the scanline S3 will be ↓
┆19┆┆89┆┄┄pulled low.↲
┆84┆In the address 0431(H) the scanline S3 will be ↓
┆19┆┆89┆┄┄pulled low.↲
╞ ┆84┆In the address 0331(H) none of the scanline will be ↓
┆19┆┆89┆┄┄pulled low. All lines will be in the high impedance ↓
┆19┆┆89┆┄┄state.↲
╞ ┆84┆In the address 06D7(H) the scanline SX1 will be ↓
┆19┆┆89┆┄┄pulled low.↲
↲
════════════════════════════════════════════════════════════════════════
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┆a1┆The return lines↲
↲
Port 1 defines the returnlines from the keyswitch assembly ↓
(KSA751). The figure shown below shows the principal ↓
function of the returnlines, R0-R7.↲
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Example: ┆84┆Assume that the switch B0 is closed.↲
┆84┆Assume that the return-lines is read, and that the ↓
┆19┆┆89┆┄┄address for this operation is 0456(H).↲
╞ ┆84┆The S5-line is then pulled low, and the reading ↓
┆19┆┆89┆┄┄will then show that the LSB of part 1 (R0) is "0". ↓
┆19┆┆89┆┄┄This will mean that B0 is closed.↲
┆84┆The MSB of part 1 (R7) will be "1" since B7 is ↓
┆19┆┆89┆┄┄open.↲
┆84┆If the reading of part 1 was done while the address ↓
┆19┆┆89┆┄┄was e.g. 050F(H) then the LSB of part 1 (R0) will ↓
┆19┆┆89┆┄┄reflect the status of switch A0.↲
════════════════════════════════════════════════════════════════════════
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┆a1┆The nationality switch↲
↲
SW1 in the KBC751 diagram is the nationality switch. This ↓
switch is a binary-count switch. The switchfunction is ↓
described in the following scheme.↲
┆a1┆ ↲
┆a1┆┆e1┆ SX1┆a1┆┆e1┆ SX2 ↲
┆a1┆ LOW LOW ↲
┆a1┆ Pin pair: 7-9 6-12 4-14 1-15 T1 T0 T1 T0 ↲
┆a1┆ switch position 0 O O O O L L L L ↲
┆a1┆ 1 O O O S L H L L ↲
┆a1┆ 2 O O S O L L L H ↲
┆a1┆ 3 O O S S L H L H ↲
┆a1┆ 4 O S O O H L L L ↲
┆a1┆ 5 O S O S H H L L ↲
┆a1┆ 6 O S S O H L L H ↲
┆a1┆ 7 O S S S H H L H ↲
┆a1┆ 8 S O O O L L H L ↲
┆a1┆ 9 S O O S L H H L ↲
┆a1┆ A S O S O L L H H ↲
┆a1┆ B S O S S L H H H ↲
┆a1┆ C S S O O H L H L ↲
┆a1┆ D S S O S H H H L ↲
┆a1┆ E S S S O H L H H ↲
┆a1┆ F S S S S H H H H ↲
↲
S = Shorted O = Open L = Low H = High↲
↲
To the right in scheme is the state of the two test inputs ↓
shown; as a function of the switch position and the state ↓
off the two scanlines (IC no. 3 pin 10 and 12).↲
↲
════════════════════════════════════════════════════════════════════════
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┆a1┆The handshake↲
↲
Port 1 and 2 of the 8039 microcomputer has a special ↓
feature: Each bit in the ports can function as both an input ↓
and an outputline. this feature is used in making the ↓
DATAOUT-line bidirectional.↲
↲
The DATAOUT-line is, when inactive, pulled high via an 50 K ↓
Ohm resistor located inside the 8039.↲
↲
The internal structure of the I/O-parts is shown below.↲
↲
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Whenever the computer is ┆a1┆not┆e1┆ ready for receiving data from ↓
the keyboard, the computer will pull the DATAOUT-line low. ↓
this low level will be detected at port 2's bit no. 4.↲
↲
This handshake feature is a very efficient way to avoid ↓
overrun in the keyboard-receiver-circuit.↲
↲
┆a1┆The click device↲
↲
In order to simulate the "click"-sound of a ordinary ↓
typewriter, the KBC751/KBC752 is equipped with a relay ↓
(RL1). This relay can be used to create a "click"-sound ↓
whenever a key is pressed. The relay is controlled by bit ↓
no. 6 in port 2. A low voltage on this pin will turn on the ↓
relay.↲
↲
════════════════════════════════════════════════════════════════════════
↓
In order to create a well defined "click"-sound, the pulse ↓
to the relay is as follows:↲
↲
╞ H ┆a1┆ ┆e1┆ ┆a1┆ ↲
L ┆a1┆ ↲
9mS↲
↲
┆a1┆Mouse connection↲
↲
KBC751/752 is prepared for the connection of a mouse. The ↓
mouse will send serial data to the KBC at a baudrate of ↓
1200. The KBC is then to pass on the mouse-information to ↓
the computer.↲
↲
Two types of mouseconnectors can be used; this is shown by ↓
the double layout of J3 (J3A) in fig. 2.1.↲
════════════════════════════════════════════════════════════════════════
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┆a1┆┆b0┆3. THE KEY SWITCH ASSEMBLY (KSA751)↲
↲
The KSA is simply the printed circuit board where the ↓
switches are mounted. The diagram is shown on page 18.↲
↲
↲
┆b0┆┆a1┆3.1 The Phantom Phenomenon↲
↲
The KSA is very simple but there is still a problem ↓
concerning the detection of depressed keys. Consider the ↓
example shown below:↲
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If S0 is pulled low, R0 and R2 will also be pulled low, ↓
indicating that A and E are closed. The next step in the ↓
scanningprocedure will now be to pull S1 low. R0-R2 will now ↓
be high indicating that none of the switches B, C and F are ↓
closed. The situation described here will be normal.↲
↲
Consider now this situation:↲
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When S0 is pulled low, R0 and R2 will be pulled low ↓
indicating that A and E is closed. When now S1 is being ↓
pulled low, R0 ┆a1┆and┆e1┆ R2 will be pulled low. This would ↓
normally indicate that F is closed, but this is actually not ↓
so. This condition is called a phantom condition. The ↓
condition is caused by the connection from B to A and to E. ↓
This is shown in the figure. We will see that the phantom ↓
condition will occur whenever the switches in 3 corners of a ↓
layout switch quadrangle is closed. The effect of the ↓
phantom conditionis that two scanlines (here S0 and S1) will ↓
look as though they were equal. I.e. that A and E are closed ↓
┆a1┆and┆e1┆ B and F are closed.↲
↲
The equality will in the program be used as a criteria for ↓
the presence of a phantom condition.↲
↲
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┆b0┆┆a1┆4. ╞ THE MICROPROGRAM↲
↲
The microprogram for the 8039 single chip micro-computer is ↓
stored in a 2716PROM.↲
↲
There exists 3 versions of the PROM:↲
↲
ROC191 ┆84┆is the originally PROM with no mouse-support.↲
↲
ROC315 ┆84┆is basicly a ROC191 except for the selftest-↓
┆19┆┆88┆┄┄routine. ROC315 will transmit an error-code when a ↓
┆19┆┆88┆┄┄key is depressed during power-up.↲
↲
ROC405 ┆84┆is basicly a ROC315 with a mouse-handling-routine ↓
┆19┆┆88┆┄┄added.↲
↲
↲
┆a1┆┆b0┆4.1 Error-Codes↲
↲
When power is applied the KBC performs a selftest. The test ↓
is divided into 3 "sub-tests" which are performed in the ↓
sequence shown below:↲
↲
1. ┆84┆First the PROM is being testet for a zero checksum. If ↓
┆19┆┆83┆┄┄this test fails 4 "cliks" are being transmitted and the ↓
┆19┆┆83┆┄┄"position code" 254 decimal is send to the computer.↲
↲
2. ┆84┆The keyswitch-assembly is then being tested for any ↓
┆19┆┆83┆┄┄depressed key during power-up. If a depressed key is ↓
┆19┆┆83┆┄┄detected 1 "click" is transmitted and 253 decimal is send ↓
┆19┆┆83┆┄┄to the computer.↲
↲
════════════════════════════════════════════════════════════════════════
↓
3. ┆84┆Port 2 are the 8039 microcomputer is then being tested. ↓
┆19┆┆83┆┄┄The test fails if the setup value written to the port ↓
┆19┆┆83┆┄┄does not match the actual read value. If the test fails ↓
┆19┆┆83┆┄┄2 "clicks" are transmitted and 252 decimal is send to the ↓
┆19┆┆83┆┄┄computer.↲
↲
If no error conditionis detected 3 "clicks" are transmitted ↓
and 255 decimal is send to the computer.↲
↲
════════════════════════════════════════════════════════════════════════
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┆06┆┆a1┆CODE ASSIGNMENT↲
↲
┆a1┆CODE╞ DECRIPTION╞ ╞ ↲
255╞ ╞ OK-code↲
214↲
.↲
.╞ ╞ Available error-codes↲
.↲
244↲
243↲
.↲
.╞ ╞ Nationality codes↲
.↲
228↲
227╞ ╞ Not used↲
226↲
.↲
.╞ ╞ Release codes↲
.↲
129↲
128↲
.↲
.╞ ╞ Not used↲
.↲
99↲
98↲
.↲
.╞ ╞ Position codes↲
.↲
.↲
1↲
0╞ ╞ Not used↲
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┆1a┆┆1a┆(KSA751)↲
↲
The KSA is simply the printed circuit board where thne, of the scanlines S0-S12 an
0x0000…0020 (0,) 00 00 00 00 00 00 00 00 42 03 06 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 4e 00 00 00 ┆ B N ┆
0x0020…0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ┆ ┆
0x0040…0047 00 00 00 00 00 00 00 ┆ ┆
0x0047…0080 Params {
0x0047…0080 04 00 2d 4e 0a 00 06 00 00 00 00 03 01 3c 31 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ┆ -N <1@ ┆
0x0047…0080 00 00 00 00 00 00 00 00 05 0f 19 23 2d 37 41 4b 55 5f 69 73 7d 87 91 ff 04 ┆ #-7AKU_iså ┆
0x0047…0080 }
0x0080…00a0 b0 a1 f0 e1 06 69 0d 0a 0d 0a b0 a1 54 41 42 4c 45 20 4f 46 20 43 4f 4e 54 45 4e 54 53 05 50 41 ┆ i TABLE OF CONTENTS PA┆
0x00a0…00c0 47 45 0d 0a 0d 0a 31 2e 20 20 44 45 53 43 52 49 50 54 49 4f 4e 20 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e ┆GE 1. DESCRIPTION ..........┆
0x00c0…00e0 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 20 20 ┆.............................. ┆
0x00e0…0100 20 31 0d 0a 20 20 20 20 31 2e 31 20 20 48 61 72 64 77 61 72 65 20 53 75 72 76 65 79 20 2e 2e 2e ┆ 1 1.1 Hardware Survey ...┆
0x0100…0120 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 20 20 20 34 ┆............................ 4┆
0x0120…0140 0d 0a 0d 0a 32 2e 20 20 54 48 45 20 4b 45 59 42 4f 41 52 44 20 43 4f 4e 54 52 4f 4c 4c 45 52 20 ┆ 2. THE KEYBOARD CONTROLLER ┆
0x0140…0160 28 4b 42 43 37 35 31 2f 4b 42 43 37 35 32 29 20 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 05 36 0d 0a ┆(KBC751/KBC752) ............ 6 ┆
0x0160…0180 20 20 20 20 32 2e 31 20 20 4c 6f 67 69 63 20 44 69 61 67 72 61 6d 73 20 61 6e 64 20 46 75 6e 63 ┆ 2.1 Logic Diagrams and Func┆
0x0180…01a0 74 69 6f 6e 61 6c 20 44 65 73 63 72 69 70 74 69 6f 6e 20 2e 2e 2e 2e 2e 05 38 0d 0a 20 20 20 20 ┆tional Description ..... 8 ┆
0x01a0…01c0 32 2e 32 20 20 53 70 65 63 69 61 6c 20 48 61 72 64 77 61 72 65 20 46 65 61 74 75 72 65 73 20 2e ┆2.2 Special Hardware Features .┆
0x01c0…01e0 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 05 31 31 0d 0a 0d 0a 33 2e 20 20 54 ┆.................... 11 3. T┆
0x01e0…0200 48 45 20 4b 45 59 20 53 57 49 54 43 48 20 41 53 53 45 4d 42 4c 59 20 28 4b 53 41 37 35 31 29 20 ┆HE KEY SWITCH ASSEMBLY (KSA751) ┆
0x0200…0220 (1,) 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 20 20 31 36 0d 0a 20 20 20 20 33 2e 31 ┆................... 16 3.1┆
0x0220…0240 20 20 54 68 65 20 50 68 61 6e 74 6f 6d 20 50 68 65 6e 6f 6d 65 6e 6f 6e 20 2e 2e 2e 2e 2e 2e 2e ┆ The Phantom Phenomenon .......┆
0x0240…0260 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 20 20 31 36 0d 0a 0d 0a 34 2e 20 20 54 48 45 ┆................. 16 4. THE┆
0x0260…0280 20 4d 49 43 52 4f 50 52 4f 47 52 41 4d 20 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e ┆ MICROPROGRAM ..................┆
0x0280…02a0 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 05 31 39 0d 0a 20 20 20 20 34 2e 31 20 20 45 ┆................. 19 4.1 E┆
0x02a0…02c0 72 72 6f 72 2d 43 6f 64 65 73 20 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e ┆rror-Codes .....................┆
0x02c0…02d3 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 05 31 39 0d 0a ┆.............. 19 ┆
0x02d3…02d6 FormFeed {
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0x02d6…02de 0a 06 69 69 0d 0a 0d 0a ┆ ii ┆
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0x02e5…0300 0a 14 b3 a1 b0 e1 06 0b 0d 0a b0 a1 31 2e 20 44 45 53 43 52 49 50 54 49 4f 4e 0d ┆ 1. DESCRIPTION ┆
0x0300…0320 0a 0d 0a 54 68 65 20 52 43 37 33 30 20 69 73 20 74 68 65 20 6b 65 79 62 6f 61 72 64 20 66 6f 72 ┆ The RC730 is the keyboard for┆
0x0320…0340 20 74 68 65 20 52 43 37 35 30 20 6d 69 63 72 6f 63 6f 6d 70 75 74 65 72 2e 20 54 68 65 20 0a 6b ┆ the RC750 microcomputer. The k┆
0x0340…0360 65 79 62 6f 61 72 64 20 69 73 20 62 61 73 65 64 20 6f 6e 20 74 68 65 20 70 6f 73 69 74 69 6f 6e ┆eyboard is based on the position┆
0x0360…0380 2d 63 6f 64 65 20 70 72 69 6e 63 69 70 6c 65 2e 20 49 2e 65 2e 20 74 68 61 74 20 0a 61 20 64 65 ┆-code principle. I.e. that a de┆
0x0380…03a0 70 72 65 73 73 69 6f 6e 20 6f 66 20 61 20 6b 65 79 20 72 65 73 75 6c 74 73 20 69 6e 20 74 68 65 ┆pression of a key results in the┆
0x03a0…03c0 20 74 72 61 6e 73 6d 69 73 73 69 6f 6e 20 6f 66 20 61 20 0a 70 6f 73 69 74 69 6f 6e 20 63 6f 64 ┆ transmission of a position cod┆
0x03c0…03e0 65 2e 20 54 68 65 72 65 66 6f 72 65 20 74 68 65 20 68 6f 73 74 20 63 6f 6d 70 75 74 65 72 20 6d ┆e. Therefore the host computer m┆
0x03e0…0400 75 73 74 20 70 65 72 66 6f 72 6d 20 61 20 0a 74 72 61 6e 73 6c 61 74 69 6f 6e 20 66 72 6f 6d 20 ┆ust perform a translation from ┆
0x0400…0420 (2,) 70 6f 73 69 74 69 6f 6e 20 63 6f 64 65 73 20 74 6f 20 65 2e 67 2e 20 41 53 43 49 49 2e 20 57 68 ┆position codes to e.g. ASCII. Wh┆
0x0420…0440 65 6e 20 61 20 6b 65 79 20 69 73 20 0a 72 65 6c 65 61 73 65 64 2c 20 31 32 38 20 28 64 65 63 69 ┆en a key is released, 128 (deci┆
0x0440…0460 6d 61 6c 29 20 69 73 20 61 64 64 65 64 20 74 6f 20 74 68 65 20 70 6f 73 69 74 69 6f 6e 20 63 6f ┆mal) is added to the position co┆
0x0460…0480 64 65 20 61 6e 64 20 0a 74 68 69 73 20 63 6f 64 65 20 69 73 20 74 68 65 6e 20 74 6f 20 62 65 20 ┆de and this code is then to be ┆
0x0480…04a0 74 72 61 6e 73 6d 69 74 74 65 64 2e 20 49 2e 65 2e 20 74 68 61 74 20 61 20 73 69 6e 67 6c 65 20 ┆transmitted. I.e. that a single ┆
0x04a0…04c0 0a 22 68 69 74 22 20 6f 6e 20 61 20 6b 65 79 20 72 65 73 75 6c 74 73 20 69 6e 20 74 68 65 20 74 ┆ "hit" on a key results in the t┆
0x04c0…04e0 72 61 6e 73 6d 69 73 73 69 6f 6e 20 6f 66 20 32 20 63 6f 64 65 73 2e 20 54 68 65 20 0a 70 6f 73 ┆ransmission of 2 codes. The pos┆
0x04e0…0500 69 74 69 6f 6e 20 63 6f 64 65 20 61 6c 6c 6f 63 61 74 69 6f 6e 20 69 73 20 73 68 6f 77 6e 20 69 ┆ition code allocation is shown i┆
0x0500…0520 6e 20 66 69 67 2e 20 31 2e 32 2e 0d 0a 0d 0a 54 68 65 20 70 6f 73 69 74 69 6f 6e 20 63 6f 64 65 ┆n fig. 1.2. The position code┆
0x0520…0540 73 20 69 73 20 74 72 61 6e 73 6d 69 74 74 65 64 20 74 6f 20 74 68 65 20 68 6f 73 74 20 69 6e 20 ┆s is transmitted to the host in ┆
0x0540…0560 61 20 73 65 72 69 61 6c 20 0a 66 6f 72 6d 2e 20 54 68 65 20 6b 65 79 62 6f 61 72 64 20 70 72 6f ┆a serial form. The keyboard pro┆
0x0560…0580 76 69 64 65 73 20 62 6f 74 68 20 64 61 74 61 20 61 6e 64 20 63 6c 6f 63 6b 20 69 6e 66 6f 72 6d ┆vides both data and clock inform┆
0x0580…058a 61 74 69 6f 6e 2e 0d 0a 0d 0a ┆ation. ┆
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0x058d…05a0 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a ┆ ┆
0x05a0…05c0 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a ┆ ┆
0x05c0…05e0 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 06 46 69 67 75 72 65 20 31 2e 31 3a 20 4b 65 79 ┆ Figure 1.1: Key┆
0x05e0…05ef 62 6f 61 72 64 20 6c 61 79 6f 75 74 2e 0d 0a ┆board layout. ┆
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0x05f2…0600 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d ┆ ┆
0x0600…0620 (3,) 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d ┆ ┆
0x0620…0640 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 06 46 69 67 75 72 65 20 31 2e 32 ┆ Figure 1.2┆
0x0640…065c 3a 20 50 6f 73 69 74 69 6f 6e 63 6f 64 65 20 61 6c 6c 6f 63 61 74 69 6f 6e 2e 0d 0a ┆: Positioncode allocation. ┆
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0x065f…0660 0a ┆ ┆
0x0660…0680 b0 a1 31 2e 31 20 48 61 72 64 77 61 72 65 20 53 75 72 76 65 79 0d 0a 0d 0a 54 68 65 20 52 43 37 ┆ 1.1 Hardware Survey The RC7┆
0x0680…06a0 33 30 20 6b 65 79 62 6f 61 72 64 20 63 6f 6e 73 69 73 74 73 20 66 6f 20 74 77 6f 20 6d 6f 64 75 ┆30 keyboard consists fo two modu┆
0x06a0…06c0 6c 65 73 3a 20 4b 42 43 37 35 31 2f 4b 42 43 37 35 32 20 0a 61 6e 64 20 4b 53 41 37 35 31 2e 0d ┆les: KBC751/KBC752 and KSA751. ┆
0x06c0…06e0 0a 0d 0a 4b 42 43 37 35 31 20 69 73 20 74 68 65 20 63 6f 6e 74 72 6f 6c 6c 65 72 20 6d 6f 64 75 ┆ KBC751 is the controller modu┆
0x06e0…0700 6c 65 20 61 6e 64 20 4b 53 41 37 35 31 20 69 73 20 73 69 6d 70 6c 79 20 74 68 65 20 50 43 42 20 ┆le and KSA751 is simply the PCB ┆
0x0700…0720 0a 77 68 65 72 65 20 74 68 65 20 6b 65 79 73 77 69 74 63 68 65 73 20 61 72 65 20 6d 6f 75 6e 74 ┆ where the keyswitches are mount┆
0x0720…0740 65 64 2e 0d 0a 0d 0a 54 68 65 20 63 6f 6e 74 72 6f 6c 6c 65 72 20 70 65 72 66 6f 72 6d 73 20 74 ┆ed. The controller performs t┆
0x0740…0760 68 65 20 22 72 65 61 64 69 6e 67 22 20 6f 66 20 74 68 65 20 73 77 69 74 63 68 65 73 2c 20 74 68 ┆he "reading" of the switches, th┆
0x0760…0780 65 20 0a 74 72 61 6e 73 6d 69 73 73 69 6f 6e 20 6f 66 20 70 6f 73 69 74 69 6f 6e 20 63 6f 64 65 ┆e transmission of position code┆
0x0780…07a0 73 20 61 6e 64 20 74 68 65 20 67 65 6e 65 72 61 74 69 6f 6e 20 6f 66 20 0a 22 6b 65 79 73 77 69 ┆s and the generation of "keyswi┆
0x07a0…07c0 74 63 68 63 6c 69 63 6b 73 22 2e 20 54 68 65 20 63 6f 6e 74 72 6f 6c 6c 65 72 20 68 61 73 20 61 ┆tchclicks". The controller has a┆
0x07c0…07e0 6c 73 6f 20 67 6f 74 20 61 20 63 6f 6e 6e 65 63 74 6f 72 20 0a 77 68 69 63 68 20 69 73 20 69 6e ┆lso got a connector which is in┆
0x07e0…0800 74 65 6e 64 65 64 20 74 6f 20 62 65 20 75 73 65 64 20 69 6e 20 63 6f 6e 6a 75 6e 63 74 69 6f 6e ┆tended to be used in conjunction┆
0x0800…0820 (4,) 20 77 69 74 68 20 61 20 6d 6f 75 73 65 2e 20 0a 46 69 67 2e 20 31 2e 33 20 73 68 6f 77 73 20 74 ┆ with a mouse. Fig. 1.3 shows t┆
0x0820…0840 68 65 20 70 68 79 73 69 63 61 6c 20 69 6e 74 65 72 63 6f 6e 6e 65 63 74 69 6f 6e 20 6f 66 20 74 ┆he physical interconnection of t┆
0x0840…0860 68 65 20 6d 6f 64 75 6c 65 73 2e 0d 0a 0d 0a 54 68 65 20 63 6f 6e 6e 65 63 74 69 6f 6e 20 74 6f ┆he modules. The connection to┆
0x0860…0880 20 74 68 65 20 63 6f 6d 70 75 74 65 72 20 69 73 20 6d 61 64 65 20 74 68 72 6f 75 67 68 20 74 68 ┆ the computer is made through th┆
0x0880…08a0 65 20 63 61 62 6c 65 20 0a 4b 42 4c 35 37 34 2e 20 54 68 65 20 64 65 66 69 6e 69 74 69 6f 6e 20 ┆e cable KBL574. The definition ┆
0x08a0…08c0 6f 66 20 74 68 65 20 63 61 62 6c 65 20 69 73 20 61 73 20 66 6f 6c 6c 6f 77 73 3a 0d 0a 0d 0a 06 ┆of the cable is as follows: ┆
0x08c0…08e0 20 20 20 20 20 20 20 20 20 20 20 20 50 69 6e 20 31 3a 20 53 74 72 6f 62 65 20 43 6c 6f 63 6b 20 ┆ Pin 1: Strobe Clock ┆
0x08e0…0900 66 72 6f 6d 20 6b 65 79 62 6f 61 72 64 0d 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆from keyboard ┆
0x0900…0920 20 20 20 20 20 20 20 32 3a 20 53 65 72 69 61 6c 20 44 61 74 61 20 66 72 6f 6d 20 6b 65 79 62 6f ┆ 2: Serial Data from keybo┆
0x0920…0940 61 72 64 0d 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 33 3a 20 ┆ard 3: ┆
0x0940…0960 6e 6f 20 63 6f 6e 6e 65 63 74 69 6f 6e 0d 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆no connection ┆
0x0960…0980 20 20 20 20 20 20 20 34 3a 20 30 20 56 0d 0a 46 72 6f 6e 74 20 76 69 65 77 20 20 20 20 20 20 20 ┆ 4: 0 V Front view ┆
0x0980…09a0 20 20 20 20 20 20 20 35 3a 20 36 2c 35 20 56 20 2d 20 37 2c 35 20 56 20 73 75 70 70 6c 79 0d 0a ┆ 5: 6,5 V - 7,5 V supply ┆
0x09a0…09c0 35 50 20 44 49 4e 2d 63 6f 6e 6e 65 63 74 6f 72 20 20 20 20 53 68 69 65 6c 64 20 63 6f 6e 6e 65 ┆5P DIN-connector Shield conne┆
0x09c0…09de 63 74 65 64 20 74 6f 20 68 6f 75 73 69 6e 67 0d 0a 28 44 49 4e 20 34 31 35 32 34 29 0d 0a ┆cted to housing (DIN 41524) ┆
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0x0a00…0a20 (5,) 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a ┆ ┆
0x0a20…0a32 0d 0a 0d 0a 06 46 69 67 75 72 65 20 31 2e 33 3a 0d 0a ┆ Figure 1.3: ┆
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0x0a35…0a40 0a b0 a1 32 2e 20 54 48 45 20 4b ┆ 2. THE K┆
0x0a40…0a60 45 59 42 4f 41 52 44 20 43 4f 4e 54 52 4f 4c 4c 45 52 20 28 4b 42 43 37 35 31 2f 4b 42 43 37 35 ┆EYBOARD CONTROLLER (KBC751/KBC75┆
0x0a60…0a80 32 29 0d 0a 0d 0a 54 68 65 20 4b 42 43 37 35 31 2f 4b 42 43 37 35 32 20 69 73 20 62 61 73 65 64 ┆2) The KBC751/KBC752 is based┆
0x0a80…0aa0 20 75 70 6f 6e 20 61 20 38 30 33 39 20 73 69 6e 67 6c 65 20 63 68 69 70 20 6d 69 63 72 6f 2d 20 ┆ upon a 8039 single chip micro- ┆
0x0aa0…0ac0 0a 63 6f 6d 70 75 74 65 72 2e 20 54 68 65 20 70 72 6f 67 72 61 6d 20 66 6f 72 20 74 68 65 20 6d ┆ computer. The program for the m┆
0x0ac0…0ae0 69 63 72 6f 63 6f 6d 70 75 74 65 72 20 69 73 20 73 74 6f 72 65 64 20 69 6e 20 32 20 4b 20 0a 78 ┆icrocomputer is stored in 2 K x┆
0x0ae0…0b00 20 38 20 52 4f 4d 20 28 32 37 31 36 29 2e 20 0d 0a 0d 0a 49 6e 20 74 68 69 73 20 73 65 63 74 69 ┆ 8 ROM (2716). In this secti┆
0x0b00…0b20 6f 6e 20 74 68 65 20 68 61 72 64 77 61 72 65 20 61 72 6f 75 6e 64 20 74 68 65 20 6d 69 63 72 6f ┆on the hardware around the micro┆
0x0b20…0b40 63 6f 6d 70 75 74 65 72 20 77 69 6c 6c 20 0a 62 65 20 64 65 73 63 72 69 62 65 64 2e 20 54 68 65 ┆computer will be described. The┆
0x0b40…0b60 20 4b 42 43 37 35 31 2f 4b 42 43 37 35 32 20 61 73 73 65 6d 62 6c 79 20 64 72 61 77 69 6e 67 20 ┆ KBC751/KBC752 assembly drawing ┆
0x0b60…0b7a 69 73 20 73 68 6f 77 6e 20 69 6e 20 0a 66 69 67 2e 20 32 2e 31 2e 0d 0a 0d 0a ┆is shown in fig. 2.1. ┆
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0x0b7d…0b80 0a 0d 0a ┆ ┆
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[…0x1…]
0x0bc0…0bcc 06 46 69 67 75 72 65 20 33 3a 0d 0a ┆ Figure 3: ┆
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0x0bcf…0be0 0a b0 a1 32 2e 31 20 4c 6f 67 69 63 20 44 69 61 67 ┆ 2.1 Logic Diag┆
0x0be0…0c00 72 61 6d 73 20 61 6e 64 20 46 75 6e 63 74 69 6f 6e 61 6c 20 44 65 73 63 72 69 70 74 69 6f 6e 0d ┆rams and Functional Description ┆
0x0c00…0c20 (6,) 0a 0d 0a a1 53 69 67 6e 61 6c e1 06 a1 44 65 73 63 72 69 70 74 69 6f 6e 0d 0a 0d 0a 4d 4f 55 53 ┆ Signal Description MOUS┆
0x0c20…0c40 45 43 4f 4e 09 09 20 53 65 72 69 61 6c 20 64 61 74 61 20 69 6e 70 75 74 20 66 72 6f 6d 20 6d 6f ┆ECON Serial data input from mo┆
0x0c40…0c60 75 73 65 2e 0d 0a 52 58 09 09 09 20 52 65 74 75 72 6e 6c 69 6e 65 20 66 6f 72 20 74 68 65 20 74 ┆use. RX Returnline for the t┆
0x0c60…0c80 77 6f 20 53 48 49 46 54 2d 6b 65 79 73 2e 0d 0a 52 30 2d 37 09 09 20 52 65 74 75 72 6e 6c 69 6e ┆wo SHIFT-keys. R0-7 Returnlin┆
0x0c80…0ca0 65 73 20 66 72 6f 6d 20 74 68 65 20 4b 53 41 37 35 31 0d 0a 54 30 2c 20 54 31 09 09 20 49 6e 70 ┆es from the KSA751 T0, T1 Inp┆
0x0ca0…0cc0 75 74 20 66 72 6f 6d 20 6e 61 74 69 6f 6e 61 6c 69 74 79 20 73 77 69 74 63 68 0d 0a 44 41 30 2d ┆ut from nationality switch DA0-┆
0x0cc0…0ce0 37 20 09 09 20 44 61 74 61 2d 41 64 64 72 65 73 73 20 62 75 73 2e 0d 0a 4c 41 54 43 48 09 09 20 ┆7 Data-Address bus. LATCH ┆
0x0ce0…0d00 84 53 74 72 6f 62 65 20 73 69 67 6e 61 6c 20 70 72 65 73 65 6e 74 20 69 6e 20 74 68 65 20 6d 6f ┆ Strobe signal present in the mo┆
0x0d00…0d20 75 73 65 20 0a 19 99 80 80 63 6f 6e 6e 65 63 74 6f 72 20 4a 33 2e 0d 0a 41 4c 45 09 09 09 20 41 ┆use connector J3. ALE A┆
0x0d20…0d40 64 64 72 65 73 73 20 6c 61 74 63 68 20 65 6e 61 62 6c 65 0d 0a 50 53 45 4e 09 09 20 50 72 6f 67 ┆ddress latch enable PSEN Prog┆
0x0d40…0d60 72 61 6d 20 73 74 6f 72 65 20 65 6e 61 62 6c 65 0d 0a 41 38 2d 41 31 30 09 09 20 33 20 6d 6f 73 ┆ram store enable A8-A10 3 mos┆
0x0d60…0d80 74 20 73 69 67 6e 69 66 69 63 61 6e 74 20 61 64 64 72 65 73 73 20 62 69 74 73 2e 0d 0a 44 41 54 ┆t significant address bits. DAT┆
0x0d80…0da0 41 09 09 20 55 6e 62 75 66 66 65 72 65 64 20 44 41 54 41 4f 55 54 2d 6c 69 6e 65 0d 0a 43 4c 4f ┆A Unbuffered DATAOUT-line CLO┆
0x0da0…0dc0 43 4b 09 09 20 55 6e 62 75 66 66 65 72 65 64 20 69 6e 76 65 72 74 65 64 20 43 4c 4f 43 4b 4f 55 ┆CK Unbuffered inverted CLOCKOU┆
0x0dc0…0de0 54 20 6c 69 6e 65 0d 0a 43 4c 49 43 4b 09 09 20 84 43 6f 6e 74 72 6f 6c 73 20 74 68 65 20 61 63 ┆T line CLICK Controls the ac┆
0x0de0…0e00 74 69 76 61 74 69 6f 6e 20 6f 66 20 74 68 65 20 0a 19 99 80 80 72 65 6c 61 79 0d 0a a1 05 0d 0a ┆tivation of the relay ┆
0x0e00…0e20 (7,) 0d 0a 53 30 2d 31 32 20 20 09 09 20 53 63 61 6e 6c 69 6e 65 73 20 75 73 65 64 20 6f 6e 20 74 68 ┆ S0-12 Scanlines used on th┆
0x0e20…0e40 65 20 4b 53 41 37 35 31 0d 0a 53 58 31 2c 20 32 09 09 20 84 53 63 61 6e 6c 69 6e 65 73 20 64 65 ┆e KSA751 SX1, 2 Scanlines de┆
0x0e40…0e60 64 69 63 61 74 65 64 20 74 6f 20 74 68 65 20 0a 19 99 80 80 6e 61 74 69 6f 6e 61 6c 69 74 79 20 ┆dicated to the nationality ┆
0x0e60…0e80 73 77 69 74 63 68 20 61 6e 64 20 74 68 65 20 74 77 6f 20 0a 19 99 80 80 53 48 49 46 54 2d 6b 65 ┆switch and the two SHIFT-ke┆
0x0e80…0ea0 79 73 2e 0d 0a 44 41 54 41 4f 55 54 09 09 20 53 65 72 69 61 6c 20 64 61 74 61 20 66 72 6f 6d 20 ┆ys. DATAOUT Serial data from ┆
0x0ea0…0ec0 6b 65 79 62 6f 61 72 64 2e 0d 0a 43 4c 4f 43 4b 4f 55 54 09 09 20 53 74 72 6f 62 65 20 63 6c 6f ┆keyboard. CLOCKOUT Strobe clo┆
0x0ec0…0ed3 63 6b 20 66 72 6f 6d 20 6b 65 79 62 6f 61 72 64 2e 0d 0a ┆ck from keyboard. ┆
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0x0ee2…0f00 0a b0 a1 32 2e 32 20 53 70 65 63 69 61 6c 20 48 61 72 64 77 61 72 65 20 46 65 61 74 75 72 ┆ 2.2 Special Hardware Featur┆
0x0f00…0f20 65 73 0d 0a 0d 0a a1 54 68 65 20 6b 65 79 62 6f 61 72 64 20 73 63 61 6e 6e 69 6e 67 0d 0a 0d 0a ┆es The keyboard scanning ┆
0x0f20…0f40 54 68 65 20 73 63 61 6e 6e 69 6e 67 20 63 69 72 63 75 69 74 20 63 6f 6e 73 69 73 74 20 6f 66 20 ┆The scanning circuit consist of ┆
0x0f40…0f60 74 68 65 20 34 20 49 43 27 73 20 31 2c 20 32 2c 20 33 20 61 6e 64 20 34 2e 20 0a 54 68 65 20 49 ┆the 4 IC's 1, 2, 3 and 4. The I┆
0x0f60…0f80 43 34 20 69 73 20 61 20 34 2d 74 6f 2d 31 36 20 6c 69 6e 65 20 64 65 6d 75 6c 74 69 70 6c 65 78 ┆C4 is a 4-to-16 line demultiplex┆
0x0f80…0fa0 65 72 2e 20 54 68 65 20 49 43 27 73 20 31 2c 20 32 20 61 6e 64 20 33 20 0a 66 6f 72 6d 20 61 20 ┆er. The IC's 1, 2 and 3 form a ┆
0x0fa0…0fc0 6c 69 6e 65 20 6f 66 20 31 38 20 69 6e 76 65 72 74 65 72 73 20 77 69 74 68 20 6f 70 65 6e 20 63 ┆line of 18 inverters with open c┆
0x0fc0…0fe0 6f 6c 6c 65 63 74 6f 72 20 6f 75 74 70 75 74 73 2e 20 0a 4f 6e 65 2c 20 61 6e 64 20 6f 6e 6c 79 ┆ollector outputs. One, and only┆
0x0fe0…1000 20 6f 6e 65 2c 20 6f 66 20 74 68 65 20 73 63 61 6e 6c 69 6e 65 73 20 53 30 2d 53 31 32 20 61 6e ┆ one, of the scanlines S0-S12 an┆
0x1000…1020 (8,) 64 20 53 58 31 2c 20 32 20 77 69 6c 6c 20 0a 62 65 20 70 75 6c 6c 65 64 20 6c 6f 77 20 61 74 20 ┆d SX1, 2 will be pulled low at ┆
0x1020…1040 61 20 74 69 6d 65 2e 20 54 68 65 20 72 65 73 74 20 6f 66 20 74 68 65 20 73 63 61 6e 6c 69 6e 65 ┆a time. The rest of the scanline┆
0x1040…1060 73 20 77 69 6c 6c 20 62 65 20 0a 69 6e 20 74 68 65 20 68 69 67 68 20 69 6d 70 65 64 61 6e 63 65 ┆s will be in the high impedance┆
0x1060…1080 20 73 74 61 74 65 2e 20 54 68 65 20 6c 69 6e 65 20 74 6f 20 62 65 20 70 75 6c 6c 65 64 20 6c 6f ┆ state. The line to be pulled lo┆
0x1080…10a0 77 20 69 73 20 0a 73 65 6c 65 63 74 65 64 20 62 79 20 74 68 65 20 34 20 73 65 6c 65 63 74 6c 69 ┆w is selected by the 4 selectli┆
0x10a0…10c0 6e 65 73 20 41 2d 44 20 6f 6e 20 49 43 34 2e 0d 0a 0d 0a 54 68 65 20 73 65 6c 65 63 74 6c 69 6e ┆nes A-D on IC4. The selectlin┆
0x10c0…10e0 65 73 20 41 2d 44 20 69 73 20 63 6f 6e 6e 65 63 74 65 64 20 74 6f 20 74 68 65 20 61 64 64 72 65 ┆es A-D is connected to the addre┆
0x10e0…1100 73 73 6c 69 6e 65 73 20 41 34 2d 41 37 2e 0d 0a 0d 0a 54 68 65 20 53 54 52 4f 42 45 2d 69 6e 70 ┆sslines A4-A7. The STROBE-inp┆
0x1100…1120 75 74 20 6f 6e 20 49 43 34 20 69 73 20 63 6f 6e 6e 65 63 74 65 64 20 74 6f 20 74 68 65 20 6d 6f ┆ut on IC4 is connected to the mo┆
0x1120…1140 73 74 20 73 69 67 6e 69 66 69 63 61 6e 74 20 0a 61 64 64 72 65 73 73 62 69 74 2c 20 41 31 30 2e ┆st significant addressbit, A10.┆
0x1140…1160 20 54 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 20 66 69 67 75 72 65 20 77 69 6c 6c 20 64 65 73 63 72 ┆ The following figure will descr┆
0x1160…1180 69 62 65 20 74 68 65 20 0a 73 63 61 6e 6c 69 6e 65 20 61 64 64 72 65 73 73 69 6e 67 2e 0d 0a 0d ┆ibe the scanline addressing. ┆
0x1180…11a0 0a a1 4d 53 42 20 20 20 20 20 20 20 20 20 20 45 4e 41 42 4c 45 53 20 53 43 41 4e 4e 49 4e 47 20 ┆ MSB ENABLES SCANNING ┆
0x11a0…11c0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 4c 53 42 0d 0a a1 20 20 20 20 20 41 31 30 20 20 ┆ LSB A10 ┆
0x11c0…11e0 41 39 20 20 41 38 20 20 41 37 20 20 41 36 20 20 41 35 20 20 41 34 20 20 41 33 20 20 41 32 20 20 ┆A9 A8 A7 A6 A5 A4 A3 A2 ┆
0x11e0…1200 41 31 20 20 41 30 20 e1 20 42 49 4e 0d 0a a1 20 20 20 20 20 20 20 20 20 48 32 20 20 20 20 20 20 ┆A1 A0 BIN H2 ┆
0x1200…1220 (9,) 20 20 20 20 20 20 20 48 31 20 20 20 20 20 20 20 20 20 20 20 20 20 20 48 30 20 20 20 20 20 20 20 ┆ H1 H0 ┆
0x1220…1240 e1 20 48 45 58 0d 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 43 4f 4e 54 52 4f 4c ┆ HEX CONTROL┆
0x1240…1260 53 20 20 20 20 20 20 20 20 20 44 4f 4e 27 54 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆S DON'T ┆
0x1260…1280 20 20 20 20 53 43 41 4e 4c 49 4e 45 53 20 20 20 20 20 20 20 20 43 41 52 45 53 20 20 20 20 20 20 ┆ SCANLINES CARES ┆
0x1280…12a0 20 20 20 0d 0a 0d 0a 45 78 61 6d 70 6c 65 3a 20 84 49 6e 20 74 68 65 20 61 64 64 72 65 73 73 20 ┆ Example: In the address ┆
0x12a0…12c0 30 34 33 42 28 48 29 20 74 68 65 20 73 63 61 6e 6c 69 6e 65 20 53 33 20 77 69 6c 6c 20 62 65 20 ┆043B(H) the scanline S3 will be ┆
0x12c0…12e0 0a 19 89 80 80 70 75 6c 6c 65 64 20 6c 6f 77 2e 0d 0a 20 20 20 20 20 20 20 20 20 84 49 6e 20 74 ┆ pulled low. In t┆
0x12e0…1300 68 65 20 61 64 64 72 65 73 73 20 30 34 33 31 28 48 29 20 74 68 65 20 73 63 61 6e 6c 69 6e 65 20 ┆he address 0431(H) the scanline ┆
0x1300…1320 53 33 20 77 69 6c 6c 20 62 65 20 0a 19 89 80 80 70 75 6c 6c 65 64 20 6c 6f 77 2e 0d 0a 09 20 20 ┆S3 will be pulled low. ┆
0x1320…1340 20 20 20 84 49 6e 20 74 68 65 20 61 64 64 72 65 73 73 20 30 33 33 31 28 48 29 20 6e 6f 6e 65 20 ┆ In the address 0331(H) none ┆
0x1340…1360 6f 66 20 74 68 65 20 73 63 61 6e 6c 69 6e 65 20 77 69 6c 6c 20 62 65 20 0a 19 89 80 80 70 75 6c ┆of the scanline will be pul┆
0x1360…1380 6c 65 64 20 6c 6f 77 2e 20 41 6c 6c 20 6c 69 6e 65 73 20 77 69 6c 6c 20 62 65 20 69 6e 20 74 68 ┆led low. All lines will be in th┆
0x1380…13a0 65 20 68 69 67 68 20 69 6d 70 65 64 61 6e 63 65 20 0a 19 89 80 80 73 74 61 74 65 2e 0d 0a 09 20 ┆e high impedance state. ┆
0x13a0…13c0 20 20 20 20 84 49 6e 20 74 68 65 20 61 64 64 72 65 73 73 20 30 36 44 37 28 48 29 20 74 68 65 20 ┆ In the address 06D7(H) the ┆
0x13c0…13e0 73 63 61 6e 6c 69 6e 65 20 53 58 31 20 77 69 6c 6c 20 62 65 20 0a 19 89 80 80 70 75 6c 6c 65 64 ┆scanline SX1 will be pulled┆
0x13e0…13e9 20 6c 6f 77 2e 0d 0a 0d 0a ┆ low. ┆
0x13e9…13ec FormFeed {
0x13e9…13ec 0c 80 a2 ┆ ┆
0x13e9…13ec }
0x13ec…1400 0a a1 54 68 65 20 72 65 74 75 72 6e 20 6c 69 6e 65 73 0d 0a ┆ The return lines ┆
0x1400…1420 (10,) 0d 0a 50 6f 72 74 20 31 20 64 65 66 69 6e 65 73 20 74 68 65 20 72 65 74 75 72 6e 6c 69 6e 65 73 ┆ Port 1 defines the returnlines┆
0x1420…1440 20 66 72 6f 6d 20 74 68 65 20 6b 65 79 73 77 69 74 63 68 20 61 73 73 65 6d 62 6c 79 20 0a 28 4b ┆ from the keyswitch assembly (K┆
0x1440…1460 53 41 37 35 31 29 2e 20 54 68 65 20 66 69 67 75 72 65 20 73 68 6f 77 6e 20 62 65 6c 6f 77 20 73 ┆SA751). The figure shown below s┆
0x1460…1480 68 6f 77 73 20 74 68 65 20 70 72 69 6e 63 69 70 61 6c 20 0a 66 75 6e 63 74 69 6f 6e 20 6f 66 20 ┆hows the principal function of ┆
0x1480…14a0 74 68 65 20 72 65 74 75 72 6e 6c 69 6e 65 73 2c 20 52 30 2d 52 37 2e 0d 0a 0d 0a 0d 0a 0d 0a 0d ┆the returnlines, R0-R7. ┆
0x14a0…14c0 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 45 ┆ E┆
0x14c0…14e0 78 61 6d 70 6c 65 3a 20 84 41 73 73 75 6d 65 20 74 68 61 74 20 74 68 65 20 73 77 69 74 63 68 20 ┆xample: Assume that the switch ┆
0x14e0…1500 42 30 20 69 73 20 63 6c 6f 73 65 64 2e 0d 0a 20 20 20 20 20 20 20 20 20 84 41 73 73 75 6d 65 20 ┆B0 is closed. Assume ┆
0x1500…1520 74 68 61 74 20 74 68 65 20 72 65 74 75 72 6e 2d 6c 69 6e 65 73 20 69 73 20 72 65 61 64 2c 20 61 ┆that the return-lines is read, a┆
0x1520…1540 6e 64 20 74 68 61 74 20 74 68 65 20 0a 19 89 80 80 61 64 64 72 65 73 73 20 66 6f 72 20 74 68 69 ┆nd that the address for thi┆
0x1540…1560 73 20 6f 70 65 72 61 74 69 6f 6e 20 69 73 20 30 34 35 36 28 48 29 2e 0d 0a 09 20 20 20 20 20 84 ┆s operation is 0456(H). ┆
0x1560…1580 54 68 65 20 53 35 2d 6c 69 6e 65 20 69 73 20 74 68 65 6e 20 70 75 6c 6c 65 64 20 6c 6f 77 2c 20 ┆The S5-line is then pulled low, ┆
0x1580…15a0 61 6e 64 20 74 68 65 20 72 65 61 64 69 6e 67 20 0a 19 89 80 80 77 69 6c 6c 20 74 68 65 6e 20 73 ┆and the reading will then s┆
0x15a0…15c0 68 6f 77 20 74 68 61 74 20 74 68 65 20 4c 53 42 20 6f 66 20 70 61 72 74 20 31 20 28 52 30 29 20 ┆how that the LSB of part 1 (R0) ┆
0x15c0…15e0 69 73 20 22 30 22 2e 20 0a 19 89 80 80 54 68 69 73 20 77 69 6c 6c 20 6d 65 61 6e 20 74 68 61 74 ┆is "0". This will mean that┆
0x15e0…1600 20 42 30 20 69 73 20 63 6c 6f 73 65 64 2e 0d 0a 20 20 20 20 20 20 20 20 20 84 54 68 65 20 4d 53 ┆ B0 is closed. The MS┆
0x1600…1620 (11,) 42 20 6f 66 20 70 61 72 74 20 31 20 28 52 37 29 20 77 69 6c 6c 20 62 65 20 22 31 22 20 73 69 6e ┆B of part 1 (R7) will be "1" sin┆
0x1620…1640 63 65 20 42 37 20 69 73 20 0a 19 89 80 80 6f 70 65 6e 2e 0d 0a 20 20 20 20 20 20 20 20 20 84 49 ┆ce B7 is open. I┆
0x1640…1660 66 20 74 68 65 20 72 65 61 64 69 6e 67 20 6f 66 20 70 61 72 74 20 31 20 77 61 73 20 64 6f 6e 65 ┆f the reading of part 1 was done┆
0x1660…1680 20 77 68 69 6c 65 20 74 68 65 20 61 64 64 72 65 73 73 20 0a 19 89 80 80 77 61 73 20 65 2e 67 2e ┆ while the address was e.g.┆
0x1680…16a0 20 30 35 30 46 28 48 29 20 74 68 65 6e 20 74 68 65 20 4c 53 42 20 6f 66 20 70 61 72 74 20 31 20 ┆ 050F(H) then the LSB of part 1 ┆
0x16a0…16c0 28 52 30 29 20 77 69 6c 6c 20 0a 19 89 80 80 72 65 66 6c 65 63 74 20 74 68 65 20 73 74 61 74 75 ┆(R0) will reflect the statu┆
0x16c0…16d1 73 20 6f 66 20 73 77 69 74 63 68 20 41 30 2e 0d 0a ┆s of switch A0. ┆
0x16d1…16d4 FormFeed {
0x16d1…16d4 0c 80 a3 ┆ ┆
0x16d1…16d4 }
0x16d4…16e0 0a a1 54 68 65 20 6e 61 74 69 6f 6e ┆ The nation┆
0x16e0…1700 61 6c 69 74 79 20 73 77 69 74 63 68 0d 0a 0d 0a 53 57 31 20 69 6e 20 74 68 65 20 4b 42 43 37 35 ┆ality switch SW1 in the KBC75┆
0x1700…1720 31 20 64 69 61 67 72 61 6d 20 69 73 20 74 68 65 20 6e 61 74 69 6f 6e 61 6c 69 74 79 20 73 77 69 ┆1 diagram is the nationality swi┆
0x1720…1740 74 63 68 2e 20 54 68 69 73 20 0a 73 77 69 74 63 68 20 69 73 20 61 20 62 69 6e 61 72 79 2d 63 6f ┆tch. This switch is a binary-co┆
0x1740…1760 75 6e 74 20 73 77 69 74 63 68 2e 20 54 68 65 20 73 77 69 74 63 68 66 75 6e 63 74 69 6f 6e 20 69 ┆unt switch. The switchfunction i┆
0x1760…1780 73 20 0a 64 65 73 63 72 69 62 65 64 20 69 6e 20 74 68 65 20 66 6f 6c 6c 6f 77 69 6e 67 20 73 63 ┆s described in the following sc┆
0x1780…17a0 68 65 6d 65 2e 0d 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆heme. ┆
0x17a0…17c0 20 20 20 20 20 20 20 20 20 20 20 20 20 a1 20 20 20 20 20 20 20 20 20 20 20 20 20 0d 0a 20 20 20 ┆ ┆
0x17c0…17e0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆ ┆
0x17e0…1800 20 20 20 a1 e1 20 53 58 31 a1 e1 20 20 20 53 58 32 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 ┆ SX1 SX2 ┆
0x1800…1820 (12,) 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 4c 4f 57 20 ┆ LOW ┆
0x1820…1840 20 20 4c 4f 57 20 20 20 0d 0a a1 20 50 69 6e 20 70 61 69 72 3a 20 20 20 20 20 20 20 20 20 20 37 ┆ LOW Pin pair: 7┆
0x1840…1860 2d 39 20 36 2d 31 32 20 34 2d 31 34 20 31 2d 31 35 20 54 31 20 54 30 20 54 31 20 54 30 20 0d 0a ┆-9 6-12 4-14 1-15 T1 T0 T1 T0 ┆
0x1860…1880 a1 20 73 77 69 74 63 68 20 70 6f 73 69 74 69 6f 6e 20 30 20 20 20 4f 20 20 20 4f 20 20 20 20 4f ┆ switch position 0 O O O┆
0x1880…18a0 20 20 20 20 4f 20 20 20 4c 20 20 4c 20 20 4c 20 20 4c 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 ┆ O L L L L ┆
0x18a0…18c0 20 20 20 20 20 20 20 20 31 20 20 20 4f 20 20 20 4f 20 20 20 20 4f 20 20 20 20 53 20 20 20 4c 20 ┆ 1 O O O S L ┆
0x18c0…18e0 20 48 20 20 4c 20 20 4c 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 32 20 ┆ H L L 2 ┆
0x18e0…1900 20 20 4f 20 20 20 4f 20 20 20 20 53 20 20 20 20 4f 20 20 20 4c 20 20 4c 20 20 4c 20 20 48 20 20 ┆ O O S O L L L H ┆
0x1900…1920 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 33 20 20 20 4f 20 20 20 4f 20 20 20 ┆ 3 O O ┆
0x1920…1940 20 53 20 20 20 20 53 20 20 20 4c 20 20 48 20 20 4c 20 20 48 20 20 0d 0a a1 20 20 20 20 20 20 20 ┆ S S L H L H ┆
0x1940…1960 20 20 20 20 20 20 20 20 20 20 34 20 20 20 4f 20 20 20 53 20 20 20 20 4f 20 20 20 20 4f 20 20 20 ┆ 4 O S O O ┆
0x1960…1980 48 20 20 4c 20 20 4c 20 20 4c 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆H L L L ┆
0x1980…19a0 35 20 20 20 4f 20 20 20 53 20 20 20 20 4f 20 20 20 20 53 20 20 20 48 20 20 48 20 20 4c 20 20 4c ┆5 O S O S H H L L┆
0x19a0…19c0 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 36 20 20 20 4f 20 20 20 53 20 ┆ 6 O S ┆
0x19c0…19e0 20 20 20 53 20 20 20 20 4f 20 20 20 48 20 20 4c 20 20 4c 20 20 48 20 20 0d 0a a1 20 20 20 20 20 ┆ S O H L L H ┆
0x19e0…1a00 20 20 20 20 20 20 20 20 20 20 20 20 37 20 20 20 4f 20 20 20 53 20 20 20 20 53 20 20 20 20 53 20 ┆ 7 O S S S ┆
0x1a00…1a20 (13,) 20 20 48 20 20 48 20 20 4c 20 20 48 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆ H H L H ┆
0x1a20…1a40 20 20 38 20 20 20 53 20 20 20 4f 20 20 20 20 4f 20 20 20 20 4f 20 20 20 4c 20 20 4c 20 20 48 20 ┆ 8 S O O O L L H ┆
0x1a40…1a60 20 4c 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 39 20 20 20 53 20 20 20 ┆ L 9 S ┆
0x1a60…1a80 4f 20 20 20 20 4f 20 20 20 20 53 20 20 20 4c 20 20 48 20 20 48 20 20 4c 20 20 0d 0a a1 20 20 20 ┆O O S L H H L ┆
0x1a80…1aa0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 41 20 20 20 53 20 20 20 4f 20 20 20 20 53 20 20 20 20 ┆ A S O S ┆
0x1aa0…1ac0 4f 20 20 20 4c 20 20 4c 20 20 48 20 20 48 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 ┆O L L H H ┆
0x1ac0…1ae0 20 20 20 20 42 20 20 20 53 20 20 20 4f 20 20 20 20 53 20 20 20 20 53 20 20 20 4c 20 20 48 20 20 ┆ B S O S S L H ┆
0x1ae0…1b00 48 20 20 48 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 43 20 20 20 53 20 ┆H H C S ┆
0x1b00…1b20 20 20 53 20 20 20 20 4f 20 20 20 20 4f 20 20 20 48 20 20 4c 20 20 48 20 20 4c 20 20 0d 0a a1 20 ┆ S O O H L H L ┆
0x1b20…1b40 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 44 20 20 20 53 20 20 20 53 20 20 20 20 4f 20 20 ┆ D S S O ┆
0x1b40…1b60 20 20 53 20 20 20 48 20 20 48 20 20 48 20 20 4c 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 ┆ S H H H L ┆
0x1b60…1b80 20 20 20 20 20 20 45 20 20 20 53 20 20 20 53 20 20 20 20 53 20 20 20 20 4f 20 20 20 48 20 20 4c ┆ E S S S O H L┆
0x1b80…1ba0 20 20 48 20 20 48 20 20 0d 0a a1 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 46 20 20 20 ┆ H H F ┆
0x1ba0…1bc0 53 20 20 20 53 20 20 20 20 53 20 20 20 20 53 20 20 20 48 20 20 48 20 20 48 20 20 48 20 20 0d 0a ┆S S S S H H H H ┆
0x1bc0…1be0 0d 0a 53 20 3d 20 53 68 6f 72 74 65 64 20 20 4f 20 3d 20 4f 70 65 6e 20 20 4c 20 3d 20 4c 6f 77 ┆ S = Shorted O = Open L = Low┆
0x1be0…1c00 20 20 48 20 3d 20 48 69 67 68 0d 0a 0d 0a 54 6f 20 74 68 65 20 72 69 67 68 74 20 69 6e 20 73 63 ┆ H = High To the right in sc┆
0x1c00…1c20 (14,) 68 65 6d 65 20 69 73 20 74 68 65 20 73 74 61 74 65 20 6f 66 20 74 68 65 20 74 77 6f 20 74 65 73 ┆heme is the state of the two tes┆
0x1c20…1c40 74 20 69 6e 70 75 74 73 20 0a 73 68 6f 77 6e 3b 20 61 73 20 61 20 66 75 6e 63 74 69 6f 6e 20 6f ┆t inputs shown; as a function o┆
0x1c40…1c60 66 20 74 68 65 20 73 77 69 74 63 68 20 70 6f 73 69 74 69 6f 6e 20 61 6e 64 20 74 68 65 20 73 74 ┆f the switch position and the st┆
0x1c60…1c80 61 74 65 20 0a 6f 66 66 20 74 68 65 20 74 77 6f 20 73 63 61 6e 6c 69 6e 65 73 20 28 49 43 20 6e ┆ate off the two scanlines (IC n┆
0x1c80…1c98 6f 2e 20 33 20 70 69 6e 20 31 30 20 61 6e 64 20 31 32 29 2e 0d 0a 0d 0a ┆o. 3 pin 10 and 12). ┆
0x1c98…1c9b FormFeed {
0x1c98…1c9b 0c 80 a0 ┆ ┆
0x1c98…1c9b }
0x1c9b…1ca0 0a a1 54 68 65 ┆ The┆
0x1ca0…1cc0 20 68 61 6e 64 73 68 61 6b 65 0d 0a 0d 0a 50 6f 72 74 20 31 20 61 6e 64 20 32 20 6f 66 20 74 68 ┆ handshake Port 1 and 2 of th┆
0x1cc0…1ce0 65 20 38 30 33 39 20 6d 69 63 72 6f 63 6f 6d 70 75 74 65 72 20 68 61 73 20 61 20 73 70 65 63 69 ┆e 8039 microcomputer has a speci┆
0x1ce0…1d00 61 6c 20 0a 66 65 61 74 75 72 65 3a 20 45 61 63 68 20 62 69 74 20 69 6e 20 74 68 65 20 70 6f 72 ┆al feature: Each bit in the por┆
0x1d00…1d20 74 73 20 63 61 6e 20 66 75 6e 63 74 69 6f 6e 20 61 73 20 62 6f 74 68 20 61 6e 20 69 6e 70 75 74 ┆ts can function as both an input┆
0x1d20…1d40 20 0a 61 6e 64 20 61 6e 20 6f 75 74 70 75 74 6c 69 6e 65 2e 20 74 68 69 73 20 66 65 61 74 75 72 ┆ and an outputline. this featur┆
0x1d40…1d60 65 20 69 73 20 75 73 65 64 20 69 6e 20 6d 61 6b 69 6e 67 20 74 68 65 20 0a 44 41 54 41 4f 55 54 ┆e is used in making the DATAOUT┆
0x1d60…1d80 2d 6c 69 6e 65 20 62 69 64 69 72 65 63 74 69 6f 6e 61 6c 2e 0d 0a 0d 0a 54 68 65 20 44 41 54 41 ┆-line bidirectional. The DATA┆
0x1d80…1da0 4f 55 54 2d 6c 69 6e 65 20 69 73 2c 20 77 68 65 6e 20 69 6e 61 63 74 69 76 65 2c 20 70 75 6c 6c ┆OUT-line is, when inactive, pull┆
0x1da0…1dc0 65 64 20 68 69 67 68 20 76 69 61 20 61 6e 20 35 30 20 4b 20 0a 4f 68 6d 20 72 65 73 69 73 74 6f ┆ed high via an 50 K Ohm resisto┆
0x1dc0…1de0 72 20 6c 6f 63 61 74 65 64 20 69 6e 73 69 64 65 20 74 68 65 20 38 30 33 39 2e 0d 0a 0d 0a 54 68 ┆r located inside the 8039. Th┆
0x1de0…1e00 65 20 69 6e 74 65 72 6e 61 6c 20 73 74 72 75 63 74 75 72 65 20 6f 66 20 74 68 65 20 49 2f 4f 2d ┆e internal structure of the I/O-┆
0x1e00…1e20 (15,) 70 61 72 74 73 20 69 73 20 73 68 6f 77 6e 20 62 65 6c 6f 77 2e 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d ┆parts is shown below. ┆
0x1e20…1e40 0a 0d 0a 0d 0a 57 68 65 6e 65 76 65 72 20 74 68 65 20 63 6f 6d 70 75 74 65 72 20 69 73 20 a1 6e ┆ Whenever the computer is n┆
0x1e40…1e60 6f 74 e1 20 72 65 61 64 79 20 66 6f 72 20 72 65 63 65 69 76 69 6e 67 20 64 61 74 61 20 66 72 6f ┆ot ready for receiving data fro┆
0x1e60…1e80 6d 20 0a 74 68 65 20 6b 65 79 62 6f 61 72 64 2c 20 74 68 65 20 63 6f 6d 70 75 74 65 72 20 77 69 ┆m the keyboard, the computer wi┆
0x1e80…1ea0 6c 6c 20 70 75 6c 6c 20 74 68 65 20 44 41 54 41 4f 55 54 2d 6c 69 6e 65 20 6c 6f 77 2e 20 0a 74 ┆ll pull the DATAOUT-line low. t┆
0x1ea0…1ec0 68 69 73 20 6c 6f 77 20 6c 65 76 65 6c 20 77 69 6c 6c 20 62 65 20 64 65 74 65 63 74 65 64 20 61 ┆his low level will be detected a┆
0x1ec0…1ee0 74 20 70 6f 72 74 20 32 27 73 20 62 69 74 20 6e 6f 2e 20 34 2e 0d 0a 0d 0a 54 68 69 73 20 68 61 ┆t port 2's bit no. 4. This ha┆
0x1ee0…1f00 6e 64 73 68 61 6b 65 20 66 65 61 74 75 72 65 20 69 73 20 61 20 76 65 72 79 20 65 66 66 69 63 69 ┆ndshake feature is a very effici┆
0x1f00…1f20 65 6e 74 20 77 61 79 20 74 6f 20 61 76 6f 69 64 20 0a 6f 76 65 72 72 75 6e 20 69 6e 20 74 68 65 ┆ent way to avoid overrun in the┆
0x1f20…1f40 20 6b 65 79 62 6f 61 72 64 2d 72 65 63 65 69 76 65 72 2d 63 69 72 63 75 69 74 2e 0d 0a 0d 0a a1 ┆ keyboard-receiver-circuit. ┆
0x1f40…1f60 54 68 65 20 63 6c 69 63 6b 20 64 65 76 69 63 65 0d 0a 0d 0a 49 6e 20 6f 72 64 65 72 20 74 6f 20 ┆The click device In order to ┆
0x1f60…1f80 73 69 6d 75 6c 61 74 65 20 74 68 65 20 22 63 6c 69 63 6b 22 2d 73 6f 75 6e 64 20 6f 66 20 61 20 ┆simulate the "click"-sound of a ┆
0x1f80…1fa0 6f 72 64 69 6e 61 72 79 20 0a 74 79 70 65 77 72 69 74 65 72 2c 20 74 68 65 20 4b 42 43 37 35 31 ┆ordinary typewriter, the KBC751┆
0x1fa0…1fc0 2f 4b 42 43 37 35 32 20 69 73 20 65 71 75 69 70 70 65 64 20 77 69 74 68 20 61 20 72 65 6c 61 79 ┆/KBC752 is equipped with a relay┆
0x1fc0…1fe0 20 0a 28 52 4c 31 29 2e 20 54 68 69 73 20 72 65 6c 61 79 20 63 61 6e 20 62 65 20 75 73 65 64 20 ┆ (RL1). This relay can be used ┆
0x1fe0…2000 74 6f 20 63 72 65 61 74 65 20 61 20 22 63 6c 69 63 6b 22 2d 73 6f 75 6e 64 20 0a 77 68 65 6e 65 ┆to create a "click"-sound whene┆
0x2000…2020 (16,) 76 65 72 20 61 20 6b 65 79 20 69 73 20 70 72 65 73 73 65 64 2e 20 54 68 65 20 72 65 6c 61 79 20 ┆ver a key is pressed. The relay ┆
0x2020…2040 69 73 20 63 6f 6e 74 72 6f 6c 6c 65 64 20 62 79 20 62 69 74 20 0a 6e 6f 2e 20 36 20 69 6e 20 70 ┆is controlled by bit no. 6 in p┆
0x2040…2060 6f 72 74 20 32 2e 20 41 20 6c 6f 77 20 76 6f 6c 74 61 67 65 20 6f 6e 20 74 68 69 73 20 70 69 6e ┆ort 2. A low voltage on this pin┆
0x2060…207d 20 77 69 6c 6c 20 74 75 72 6e 20 6f 6e 20 74 68 65 20 0a 72 65 6c 61 79 2e 0d 0a 0d 0a ┆ will turn on the relay. ┆
0x207d…2080 FormFeed {
0x207d…2080 0c 80 a2 ┆ ┆
0x207d…2080 }
0x2080…20a0 0a 49 6e 20 6f 72 64 65 72 20 74 6f 20 63 72 65 61 74 65 20 61 20 77 65 6c 6c 20 64 65 66 69 6e ┆ In order to create a well defin┆
0x20a0…20c0 65 64 20 22 63 6c 69 63 6b 22 2d 73 6f 75 6e 64 2c 20 74 68 65 20 70 75 6c 73 65 20 0a 74 6f 20 ┆ed "click"-sound, the pulse to ┆
0x20c0…20e0 74 68 65 20 72 65 6c 61 79 20 69 73 20 61 73 20 66 6f 6c 6c 6f 77 73 3a 0d 0a 0d 0a 09 48 20 a1 ┆the relay is as follows: H ┆
0x20e0…2100 20 20 20 20 20 20 20 20 20 20 20 20 20 20 e1 20 20 20 20 20 20 20 20 20 20 20 a1 20 20 20 20 20 ┆ ┆
0x2100…2120 20 20 20 0d 0a 20 20 20 20 4c 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 a1 20 20 20 20 20 20 ┆ L ┆
0x2120…2140 20 20 20 20 20 0d 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 39 6d 53 ┆ 9mS┆
0x2140…2160 0d 0a 0d 0a a1 4d 6f 75 73 65 20 63 6f 6e 6e 65 63 74 69 6f 6e 0d 0a 0d 0a 4b 42 43 37 35 31 2f ┆ Mouse connection KBC751/┆
0x2160…2180 37 35 32 20 69 73 20 70 72 65 70 61 72 65 64 20 66 6f 72 20 74 68 65 20 63 6f 6e 6e 65 63 74 69 ┆752 is prepared for the connecti┆
0x2180…21a0 6f 6e 20 6f 66 20 61 20 6d 6f 75 73 65 2e 20 54 68 65 20 0a 6d 6f 75 73 65 20 77 69 6c 6c 20 73 ┆on of a mouse. The mouse will s┆
0x21a0…21c0 65 6e 64 20 73 65 72 69 61 6c 20 64 61 74 61 20 74 6f 20 74 68 65 20 4b 42 43 20 61 74 20 61 20 ┆end serial data to the KBC at a ┆
0x21c0…21e0 62 61 75 64 72 61 74 65 20 6f 66 20 0a 31 32 30 30 2e 20 54 68 65 20 4b 42 43 20 69 73 20 74 68 ┆baudrate of 1200. The KBC is th┆
0x21e0…2200 65 6e 20 74 6f 20 70 61 73 73 20 6f 6e 20 74 68 65 20 6d 6f 75 73 65 2d 69 6e 66 6f 72 6d 61 74 ┆en to pass on the mouse-informat┆
0x2200…2220 (17,) 69 6f 6e 20 74 6f 20 0a 74 68 65 20 63 6f 6d 70 75 74 65 72 2e 0d 0a 0d 0a 54 77 6f 20 74 79 70 ┆ion to the computer. Two typ┆
0x2220…2240 65 73 20 6f 66 20 6d 6f 75 73 65 63 6f 6e 6e 65 63 74 6f 72 73 20 63 61 6e 20 62 65 20 75 73 65 ┆es of mouseconnectors can be use┆
0x2240…2260 64 3b 20 74 68 69 73 20 69 73 20 73 68 6f 77 6e 20 62 79 20 0a 74 68 65 20 64 6f 75 62 6c 65 20 ┆d; this is shown by the double ┆
0x2260…2280 6c 61 79 6f 75 74 20 6f 66 20 4a 33 20 28 4a 33 41 29 20 69 6e 20 66 69 67 2e 20 32 2e 31 2e 0d ┆layout of J3 (J3A) in fig. 2.1. ┆
0x2280…2281 0a ┆ ┆
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0x2284…22a0 0a a1 b0 33 2e 20 54 48 45 20 4b 45 59 20 53 57 49 54 43 48 20 41 53 53 45 4d 42 4c ┆ 3. THE KEY SWITCH ASSEMBL┆
0x22a0…22c0 59 20 28 4b 53 41 37 35 31 29 0d 0a 0d 0a 54 68 65 20 4b 53 41 20 69 73 20 73 69 6d 70 6c 79 20 ┆Y (KSA751) The KSA is simply ┆
0x22c0…22e0 74 68 65 20 70 72 69 6e 74 65 64 20 63 69 72 63 75 69 74 20 62 6f 61 72 64 20 77 68 65 72 65 20 ┆the printed circuit board where ┆
0x22e0…2300 74 68 65 20 0a 73 77 69 74 63 68 65 73 20 61 72 65 20 6d 6f 75 6e 74 65 64 2e 20 54 68 65 20 64 ┆the switches are mounted. The d┆
0x2300…2320 69 61 67 72 61 6d 20 69 73 20 73 68 6f 77 6e 20 6f 6e 20 70 61 67 65 20 31 38 2e 0d 0a 0d 0a 0d ┆iagram is shown on page 18. ┆
0x2320…2340 0a b0 a1 33 2e 31 20 54 68 65 20 50 68 61 6e 74 6f 6d 20 50 68 65 6e 6f 6d 65 6e 6f 6e 0d 0a 0d ┆ 3.1 The Phantom Phenomenon ┆
0x2340…2360 0a 54 68 65 20 4b 53 41 20 69 73 20 76 65 72 79 20 73 69 6d 70 6c 65 20 62 75 74 20 74 68 65 72 ┆ The KSA is very simple but ther┆
0x2360…2380 65 20 69 73 20 73 74 69 6c 6c 20 61 20 70 72 6f 62 6c 65 6d 20 0a 63 6f 6e 63 65 72 6e 69 6e 67 ┆e is still a problem concerning┆
0x2380…23a0 20 74 68 65 20 64 65 74 65 63 74 69 6f 6e 20 6f 66 20 64 65 70 72 65 73 73 65 64 20 6b 65 79 73 ┆ the detection of depressed keys┆
0x23a0…23c0 2e 20 43 6f 6e 73 69 64 65 72 20 74 68 65 20 0a 65 78 61 6d 70 6c 65 20 73 68 6f 77 6e 20 62 65 ┆. Consider the example shown be┆
0x23c0…23e0 6c 6f 77 3a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a 49 66 20 53 30 20 69 73 20 70 ┆low: If S0 is p┆
0x23e0…2400 75 6c 6c 65 64 20 6c 6f 77 2c 20 52 30 20 61 6e 64 20 52 32 20 77 69 6c 6c 20 61 6c 73 6f 20 62 ┆ulled low, R0 and R2 will also b┆
0x2400…2420 (18,) 65 20 70 75 6c 6c 65 64 20 6c 6f 77 2c 20 0a 69 6e 64 69 63 61 74 69 6e 67 20 74 68 61 74 20 41 ┆e pulled low, indicating that A┆
0x2420…2440 20 61 6e 64 20 45 20 61 72 65 20 63 6c 6f 73 65 64 2e 20 54 68 65 20 6e 65 78 74 20 73 74 65 70 ┆ and E are closed. The next step┆
0x2440…2460 20 69 6e 20 74 68 65 20 0a 73 63 61 6e 6e 69 6e 67 70 72 6f 63 65 64 75 72 65 20 77 69 6c 6c 20 ┆ in the scanningprocedure will ┆
0x2460…2480 6e 6f 77 20 62 65 20 74 6f 20 70 75 6c 6c 20 53 31 20 6c 6f 77 2e 20 52 30 2d 52 32 20 77 69 6c ┆now be to pull S1 low. R0-R2 wil┆
0x2480…24a0 6c 20 6e 6f 77 20 0a 62 65 20 68 69 67 68 20 69 6e 64 69 63 61 74 69 6e 67 20 74 68 61 74 20 6e ┆l now be high indicating that n┆
0x24a0…24c0 6f 6e 65 20 6f 66 20 74 68 65 20 73 77 69 74 63 68 65 73 20 42 2c 20 43 20 61 6e 64 20 46 20 61 ┆one of the switches B, C and F a┆
0x24c0…24e0 72 65 20 0a 63 6c 6f 73 65 64 2e 20 54 68 65 20 73 69 74 75 61 74 69 6f 6e 20 64 65 73 63 72 69 ┆re closed. The situation descri┆
0x24e0…2500 62 65 64 20 68 65 72 65 20 77 69 6c 6c 20 62 65 20 6e 6f 72 6d 61 6c 2e 0d 0a 0d 0a 43 6f 6e 73 ┆bed here will be normal. Cons┆
0x2500…2520 69 64 65 72 20 6e 6f 77 20 74 68 69 73 20 73 69 74 75 61 74 69 6f 6e 3a 0d 0a 0d 0a 0d 0a 0d 0a ┆ider now this situation: ┆
0x2520…252a 0d 0a 0d 0a 0d 0a 0d 0a 0d 0a ┆ ┆
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0x252d…2540 0a 57 68 65 6e 20 53 30 20 69 73 20 70 75 6c 6c 65 64 20 ┆ When S0 is pulled ┆
0x2540…2560 6c 6f 77 2c 20 52 30 20 61 6e 64 20 52 32 20 77 69 6c 6c 20 62 65 20 70 75 6c 6c 65 64 20 6c 6f ┆low, R0 and R2 will be pulled lo┆
0x2560…2580 77 20 0a 69 6e 64 69 63 61 74 69 6e 67 20 74 68 61 74 20 41 20 61 6e 64 20 45 20 69 73 20 63 6c ┆w indicating that A and E is cl┆
0x2580…25a0 6f 73 65 64 2e 20 57 68 65 6e 20 6e 6f 77 20 53 31 20 69 73 20 62 65 69 6e 67 20 0a 70 75 6c 6c ┆osed. When now S1 is being pull┆
0x25a0…25c0 65 64 20 6c 6f 77 2c 20 52 30 20 a1 61 6e 64 e1 20 52 32 20 77 69 6c 6c 20 62 65 20 70 75 6c 6c ┆ed low, R0 and R2 will be pull┆
0x25c0…25e0 65 64 20 6c 6f 77 2e 20 54 68 69 73 20 77 6f 75 6c 64 20 0a 6e 6f 72 6d 61 6c 6c 79 20 69 6e 64 ┆ed low. This would normally ind┆
0x25e0…2600 69 63 61 74 65 20 74 68 61 74 20 46 20 69 73 20 63 6c 6f 73 65 64 2c 20 62 75 74 20 74 68 69 73 ┆icate that F is closed, but this┆
0x2600…2620 (19,) 20 69 73 20 61 63 74 75 61 6c 6c 79 20 6e 6f 74 20 0a 73 6f 2e 20 54 68 69 73 20 63 6f 6e 64 69 ┆ is actually not so. This condi┆
0x2620…2640 74 69 6f 6e 20 69 73 20 63 61 6c 6c 65 64 20 61 20 70 68 61 6e 74 6f 6d 20 63 6f 6e 64 69 74 69 ┆tion is called a phantom conditi┆
0x2640…2660 6f 6e 2e 20 54 68 65 20 0a 63 6f 6e 64 69 74 69 6f 6e 20 69 73 20 63 61 75 73 65 64 20 62 79 20 ┆on. The condition is caused by ┆
0x2660…2680 74 68 65 20 63 6f 6e 6e 65 63 74 69 6f 6e 20 66 72 6f 6d 20 42 20 74 6f 20 41 20 61 6e 64 20 74 ┆the connection from B to A and t┆
0x2680…26a0 6f 20 45 2e 20 0a 54 68 69 73 20 69 73 20 73 68 6f 77 6e 20 69 6e 20 74 68 65 20 66 69 67 75 72 ┆o E. This is shown in the figur┆
0x26a0…26c0 65 2e 20 57 65 20 77 69 6c 6c 20 73 65 65 20 74 68 61 74 20 74 68 65 20 70 68 61 6e 74 6f 6d 20 ┆e. We will see that the phantom ┆
0x26c0…26e0 0a 63 6f 6e 64 69 74 69 6f 6e 20 77 69 6c 6c 20 6f 63 63 75 72 20 77 68 65 6e 65 76 65 72 20 74 ┆ condition will occur whenever t┆
0x26e0…2700 68 65 20 73 77 69 74 63 68 65 73 20 69 6e 20 33 20 63 6f 72 6e 65 72 73 20 6f 66 20 61 20 0a 6c ┆he switches in 3 corners of a l┆
0x2700…2720 61 79 6f 75 74 20 73 77 69 74 63 68 20 71 75 61 64 72 61 6e 67 6c 65 20 69 73 20 63 6c 6f 73 65 ┆ayout switch quadrangle is close┆
0x2720…2740 64 2e 20 54 68 65 20 65 66 66 65 63 74 20 6f 66 20 74 68 65 20 0a 70 68 61 6e 74 6f 6d 20 63 6f ┆d. The effect of the phantom co┆
0x2740…2760 6e 64 69 74 69 6f 6e 69 73 20 74 68 61 74 20 74 77 6f 20 73 63 61 6e 6c 69 6e 65 73 20 28 68 65 ┆nditionis that two scanlines (he┆
0x2760…2780 72 65 20 53 30 20 61 6e 64 20 53 31 29 20 77 69 6c 6c 20 0a 6c 6f 6f 6b 20 61 73 20 74 68 6f 75 ┆re S0 and S1) will look as thou┆
0x2780…27a0 67 68 20 74 68 65 79 20 77 65 72 65 20 65 71 75 61 6c 2e 20 49 2e 65 2e 20 74 68 61 74 20 41 20 ┆gh they were equal. I.e. that A ┆
0x27a0…27c0 61 6e 64 20 45 20 61 72 65 20 63 6c 6f 73 65 64 20 0a a1 61 6e 64 e1 20 42 20 61 6e 64 20 46 20 ┆and E are closed and B and F ┆
0x27c0…27e0 61 72 65 20 63 6c 6f 73 65 64 2e 0d 0a 0d 0a 54 68 65 20 65 71 75 61 6c 69 74 79 20 77 69 6c 6c ┆are closed. The equality will┆
0x27e0…2800 20 69 6e 20 74 68 65 20 70 72 6f 67 72 61 6d 20 62 65 20 75 73 65 64 20 61 73 20 61 20 63 72 69 ┆ in the program be used as a cri┆
0x2800…2820 (20,) 74 65 72 69 61 20 66 6f 72 20 0a 74 68 65 20 70 72 65 73 65 6e 63 65 20 6f 66 20 61 20 70 68 61 ┆teria for the presence of a pha┆
0x2820…2833 6e 74 6f 6d 20 63 6f 6e 64 69 74 69 6f 6e 2e 0d 0a 0d 0a ┆ntom condition. ┆
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0x2836…2839 0a 0d 0a ┆ ┆
0x2839…283c FormFeed {
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0x283c…2840 0a b0 a1 34 ┆ 4┆
0x2840…2860 2e 20 09 54 48 45 20 4d 49 43 52 4f 50 52 4f 47 52 41 4d 0d 0a 0d 0a 54 68 65 20 6d 69 63 72 6f ┆. THE MICROPROGRAM The micro┆
0x2860…2880 70 72 6f 67 72 61 6d 20 66 6f 72 20 74 68 65 20 38 30 33 39 20 73 69 6e 67 6c 65 20 63 68 69 70 ┆program for the 8039 single chip┆
0x2880…28a0 20 6d 69 63 72 6f 2d 63 6f 6d 70 75 74 65 72 20 69 73 20 0a 73 74 6f 72 65 64 20 69 6e 20 61 20 ┆ micro-computer is stored in a ┆
0x28a0…28c0 32 37 31 36 50 52 4f 4d 2e 0d 0a 0d 0a 54 68 65 72 65 20 65 78 69 73 74 73 20 33 20 76 65 72 73 ┆2716PROM. There exists 3 vers┆
0x28c0…28e0 69 6f 6e 73 20 6f 66 20 74 68 65 20 50 52 4f 4d 3a 0d 0a 0d 0a 52 4f 43 31 39 31 20 20 84 69 73 ┆ions of the PROM: ROC191 is┆
0x28e0…2900 20 74 68 65 20 6f 72 69 67 69 6e 61 6c 6c 79 20 50 52 4f 4d 20 77 69 74 68 20 6e 6f 20 6d 6f 75 ┆ the originally PROM with no mou┆
0x2900…2920 73 65 2d 73 75 70 70 6f 72 74 2e 0d 0a 0d 0a 52 4f 43 33 31 35 20 20 84 69 73 20 62 61 73 69 63 ┆se-support. ROC315 is basic┆
0x2920…2940 6c 79 20 61 20 52 4f 43 31 39 31 20 65 78 63 65 70 74 20 66 6f 72 20 74 68 65 20 73 65 6c 66 74 ┆ly a ROC191 except for the selft┆
0x2940…2960 65 73 74 2d 0a 19 88 80 80 72 6f 75 74 69 6e 65 2e 20 52 4f 43 33 31 35 20 77 69 6c 6c 20 74 72 ┆est- routine. ROC315 will tr┆
0x2960…2980 61 6e 73 6d 69 74 20 61 6e 20 65 72 72 6f 72 2d 63 6f 64 65 20 77 68 65 6e 20 61 20 0a 19 88 80 ┆ansmit an error-code when a ┆
0x2980…29a0 80 6b 65 79 20 69 73 20 64 65 70 72 65 73 73 65 64 20 64 75 72 69 6e 67 20 70 6f 77 65 72 2d 75 ┆ key is depressed during power-u┆
0x29a0…29c0 70 2e 0d 0a 0d 0a 52 4f 43 34 30 35 20 20 84 69 73 20 62 61 73 69 63 6c 79 20 61 20 52 4f 43 33 ┆p. ROC405 is basicly a ROC3┆
0x29c0…29e0 31 35 20 77 69 74 68 20 61 20 6d 6f 75 73 65 2d 68 61 6e 64 6c 69 6e 67 2d 72 6f 75 74 69 6e 65 ┆15 with a mouse-handling-routine┆
0x29e0…2a00 20 0a 19 88 80 80 61 64 64 65 64 2e 0d 0a 0d 0a 0d 0a a1 b0 34 2e 31 20 45 72 72 6f 72 2d 43 6f ┆ added. 4.1 Error-Co┆
0x2a00…2a20 (21,) 64 65 73 0d 0a 0d 0a 57 68 65 6e 20 70 6f 77 65 72 20 69 73 20 61 70 70 6c 69 65 64 20 74 68 65 ┆des When power is applied the┆
0x2a20…2a40 20 4b 42 43 20 70 65 72 66 6f 72 6d 73 20 61 20 73 65 6c 66 74 65 73 74 2e 20 54 68 65 20 74 65 ┆ KBC performs a selftest. The te┆
0x2a40…2a60 73 74 20 0a 69 73 20 64 69 76 69 64 65 64 20 69 6e 74 6f 20 33 20 22 73 75 62 2d 74 65 73 74 73 ┆st is divided into 3 "sub-tests┆
0x2a60…2a80 22 20 77 68 69 63 68 20 61 72 65 20 70 65 72 66 6f 72 6d 65 64 20 69 6e 20 74 68 65 20 0a 73 65 ┆" which are performed in the se┆
0x2a80…2aa0 71 75 65 6e 63 65 20 73 68 6f 77 6e 20 62 65 6c 6f 77 3a 0d 0a 0d 0a 31 2e 20 84 46 69 72 73 74 ┆quence shown below: 1. First┆
0x2aa0…2ac0 20 74 68 65 20 50 52 4f 4d 20 69 73 20 62 65 69 6e 67 20 74 65 73 74 65 74 20 66 6f 72 20 61 20 ┆ the PROM is being testet for a ┆
0x2ac0…2ae0 7a 65 72 6f 20 63 68 65 63 6b 73 75 6d 2e 20 49 66 20 0a 19 83 80 80 74 68 69 73 20 74 65 73 74 ┆zero checksum. If this test┆
0x2ae0…2b00 20 66 61 69 6c 73 20 34 20 22 63 6c 69 6b 73 22 20 61 72 65 20 62 65 69 6e 67 20 74 72 61 6e 73 ┆ fails 4 "cliks" are being trans┆
0x2b00…2b20 6d 69 74 74 65 64 20 61 6e 64 20 74 68 65 20 0a 19 83 80 80 22 70 6f 73 69 74 69 6f 6e 20 63 6f ┆mitted and the "position co┆
0x2b20…2b40 64 65 22 20 32 35 34 20 64 65 63 69 6d 61 6c 20 69 73 20 73 65 6e 64 20 74 6f 20 74 68 65 20 63 ┆de" 254 decimal is send to the c┆
0x2b40…2b60 6f 6d 70 75 74 65 72 2e 0d 0a 0d 0a 32 2e 20 84 54 68 65 20 6b 65 79 73 77 69 74 63 68 2d 61 73 ┆omputer. 2. The keyswitch-as┆
0x2b60…2b80 73 65 6d 62 6c 79 20 69 73 20 74 68 65 6e 20 62 65 69 6e 67 20 74 65 73 74 65 64 20 66 6f 72 20 ┆sembly is then being tested for ┆
0x2b80…2ba0 61 6e 79 20 0a 19 83 80 80 64 65 70 72 65 73 73 65 64 20 6b 65 79 20 64 75 72 69 6e 67 20 70 6f ┆any depressed key during po┆
0x2ba0…2bc0 77 65 72 2d 75 70 2e 20 49 66 20 61 20 64 65 70 72 65 73 73 65 64 20 6b 65 79 20 69 73 20 0a 19 ┆wer-up. If a depressed key is ┆
0x2bc0…2be0 83 80 80 64 65 74 65 63 74 65 64 20 31 20 22 63 6c 69 63 6b 22 20 69 73 20 74 72 61 6e 73 6d 69 ┆ detected 1 "click" is transmi┆
0x2be0…2c00 74 74 65 64 20 61 6e 64 20 32 35 33 20 64 65 63 69 6d 61 6c 20 69 73 20 73 65 6e 64 20 0a 19 83 ┆tted and 253 decimal is send ┆
0x2c00…2c16 (22,) 80 80 74 6f 20 74 68 65 20 63 6f 6d 70 75 74 65 72 2e 0d 0a 0d 0a ┆ to the computer. ┆
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0x2c19…2c20 0a 33 2e 20 84 50 6f ┆ 3. Po┆
0x2c20…2c40 72 74 20 32 20 61 72 65 20 74 68 65 20 38 30 33 39 20 6d 69 63 72 6f 63 6f 6d 70 75 74 65 72 20 ┆rt 2 are the 8039 microcomputer ┆
0x2c40…2c60 69 73 20 74 68 65 6e 20 62 65 69 6e 67 20 74 65 73 74 65 64 2e 20 0a 19 83 80 80 54 68 65 20 74 ┆is then being tested. The t┆
0x2c60…2c80 65 73 74 20 66 61 69 6c 73 20 69 66 20 74 68 65 20 73 65 74 75 70 20 76 61 6c 75 65 20 77 72 69 ┆est fails if the setup value wri┆
0x2c80…2ca0 74 74 65 6e 20 74 6f 20 74 68 65 20 70 6f 72 74 20 0a 19 83 80 80 64 6f 65 73 20 6e 6f 74 20 6d ┆tten to the port does not m┆
0x2ca0…2cc0 61 74 63 68 20 74 68 65 20 61 63 74 75 61 6c 20 72 65 61 64 20 76 61 6c 75 65 2e 20 49 66 20 74 ┆atch the actual read value. If t┆
0x2cc0…2ce0 68 65 20 74 65 73 74 20 66 61 69 6c 73 20 0a 19 83 80 80 32 20 22 63 6c 69 63 6b 73 22 20 61 72 ┆he test fails 2 "clicks" ar┆
0x2ce0…2d00 65 20 74 72 61 6e 73 6d 69 74 74 65 64 20 61 6e 64 20 32 35 32 20 64 65 63 69 6d 61 6c 20 69 73 ┆e transmitted and 252 decimal is┆
0x2d00…2d20 20 73 65 6e 64 20 74 6f 20 74 68 65 20 0a 19 83 80 80 63 6f 6d 70 75 74 65 72 2e 0d 0a 0d 0a 49 ┆ send to the computer. I┆
0x2d20…2d40 66 20 6e 6f 20 65 72 72 6f 72 20 63 6f 6e 64 69 74 69 6f 6e 69 73 20 64 65 74 65 63 74 65 64 20 ┆f no error conditionis detected ┆
0x2d40…2d60 33 20 22 63 6c 69 63 6b 73 22 20 61 72 65 20 74 72 61 6e 73 6d 69 74 74 65 64 20 0a 61 6e 64 20 ┆3 "clicks" are transmitted and ┆
0x2d60…2d80 32 35 35 20 64 65 63 69 6d 61 6c 20 69 73 20 73 65 6e 64 20 74 6f 20 74 68 65 20 63 6f 6d 70 75 ┆255 decimal is send to the compu┆
0x2d80…2d88 74 65 72 2e 0d 0a 0d 0a ┆ter. ┆
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0x2d8b…2da0 0a 06 a1 43 4f 44 45 20 41 53 53 49 47 4e 4d 45 4e 54 0d 0a 0d ┆ CODE ASSIGNMENT ┆
0x2da0…2dc0 0a a1 43 4f 44 45 09 44 45 43 52 49 50 54 49 4f 4e 09 09 0d 0a 32 35 35 09 09 4f 4b 2d 63 6f 64 ┆ CODE DECRIPTION 255 OK-cod┆
0x2dc0…2de0 65 0d 0a 32 31 34 0d 0a 2e 0d 0a 2e 09 09 41 76 61 69 6c 61 62 6c 65 20 65 72 72 6f 72 2d 63 6f ┆e 214 . . Available error-co┆
0x2de0…2e00 64 65 73 0d 0a 2e 0d 0a 32 34 34 0d 0a 32 34 33 0d 0a 2e 0d 0a 2e 09 09 4e 61 74 69 6f 6e 61 6c ┆des . 244 243 . . National┆
0x2e00…2e20 (23,) 69 74 79 20 63 6f 64 65 73 0d 0a 2e 0d 0a 32 32 38 0d 0a 32 32 37 09 09 4e 6f 74 20 75 73 65 64 ┆ity codes . 228 227 Not used┆
0x2e20…2e40 0d 0a 32 32 36 0d 0a 2e 0d 0a 2e 09 09 52 65 6c 65 61 73 65 20 63 6f 64 65 73 0d 0a 2e 0d 0a 31 ┆ 226 . . Release codes . 1┆
0x2e40…2e60 32 39 0d 0a 31 32 38 0d 0a 2e 0d 0a 2e 09 09 4e 6f 74 20 75 73 65 64 0d 0a 2e 0d 0a 20 39 39 0d ┆29 128 . . Not used . 99 ┆
0x2e60…2e80 0a 20 39 38 0d 0a 2e 0d 0a 2e 09 09 50 6f 73 69 74 69 6f 6e 20 63 6f 64 65 73 0d 0a 2e 0d 0a 2e ┆ 98 . . Position codes . .┆
0x2e80…2e96 0d 0a 20 20 31 0d 0a 20 20 30 09 09 4e 6f 74 20 75 73 65 64 0d 0a ┆ 1 0 Not used ┆
0x2e96…2e99 FormFeed {
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0x2e99…2e9c 0a 0d 0a ┆ ┆
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0x2e9f…2ea0 0a ┆ ┆
0x2ea0…2ec0 1a 1a 28 4b 53 41 37 35 31 29 0d 0a 0d 0a 54 68 65 20 4b 53 41 20 69 73 20 73 69 6d 70 6c 79 20 ┆ (KSA751) The KSA is simply ┆
0x2ec0…2ee0 74 68 65 20 70 72 69 6e 74 65 64 20 63 69 72 63 75 69 74 20 62 6f 61 72 64 20 77 68 65 72 65 20 ┆the printed circuit board where ┆
0x2ee0…2f00 74 68 6e 65 2c 20 6f 66 20 74 68 65 20 73 63 61 6e 6c 69 6e 65 73 20 53 30 2d 53 31 32 20 61 6e ┆thne, of the scanlines S0-S12 an┆