Acorn Computers Limited Winchester disk 110, Руководство по обслуживанию

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7.2.5 &FC43 write IRQ enable
Run the following program:
10DIM P% 10
201
30.a
40LDA# 0
50.b
60STA &FC43
70JMP b
80]
90CALL a
Test pin 11 IC10 with a scope and check that the waveform is not stuck
either high or low. It should look like the one shown in figure 4.
Pin 9 IC10 should be logic 0.
Now run the following program:
10DIM P% 10
20[
30.a
40LDA# 1
50.b
60STA &FC43
70JMP b
80]
90CALL a
and pin 9 IC10 should now be logic 1.
7.3 Handshaking
To test the SEL/BSY handshake use the following program:
10DIM P% 20
20[
30.a
40LDA# 1
50STA &FC40
60STA &FC42
70.b
80LDA &FC41
90BEQ b
100RTS
110]
120PRINT ~USR(a) AND &FF
Press the BREAK key followed by OLD and RUN the program. The LED on the disc
controller board should illuminate, and the result 2 should be printed on the
screen after the assembler listing. (The result is the contents of the status
register, and BSY is bit Dl which corresponds to 2.)
If nothing happens and the program is typed in correctly then there is
either a loose connection or a fault in the disc controller board.
The system can be deselected by pressing BREAK.
21