Atari 400 Technical Reference Manual page 314

ERR LINE AD DR B1 B2 B3 B4 510 ( SERIAL BUS INPUT/OUTPUT CONTROLLER ) PAGE
53
2329 EC2D
25 10 AND
POKMSK
2330
EC2F 09 20 ORA #$20
iENABLE RECEIVE INTERRUPT
2331 EC31 85 10 CONTIN: STA POKMSK iSTORE NEW VALUE TO SYSTEM MASK
2332 EC33 8D OE D2 STA IRQEN iSTORE TO ACTUAL REGISTER
2333
2334
2335
EC36 A9 28 LDA
#$28 iCLOCK CH.3 WITH 1.79 MHZ
2336 EC38 80 08 02 STA AUOCTL iCLOCK CH.4 WITH CH. 3
2337
2338 EC3B A2 06 LDX
#6
i
SET PURE TONES, NO VOLUME
2339 EC3D A9 A8 LDA #$A8
·2340 EC3F A4 41 LDY SOUNDR iTEST QUIET I/O FLAG
2341 EC41 DO 02 BNE NOISE1
iNE
IS NORMAL (NOISY)
2342 EC43 A9 AO
LDA
#$AO
2343 EC45
9D 01 D2
NOISE1 : STA AUDCt. X
2344 EC48 CA DEX
2345 EC49 CA DEX
2346 EC4A 10 F9 BPL NOISE1
2347
2348 EC4C
A9 AO LDA
#$AO
2349 EC4E 8D 05 D2 STA AUDC3
iTURN OFF SOUND ON CHANNEL 3
2350 EC51 AC 00 03 LDY
DDEVIC
2351 EC54 CO 60 CPY
#CASET
2352 EC56 FO 06 BEQ CAS31
iBRANCH IF CASSETTE IS DESIRED
2353 EC58 8D 01 D2 STA AUDC1
iOTHERWISE TURN OFF CHANNELS 1 AND 2
2354 EC5B 8D 03 D2 STA AUDC2
2355
2356
2357 EC5E 60 CAS31 : RTS iRETURN
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
i
DISABLE SEND AND DISABLE RECEIVE SUBROUTINES
2369
2370 EC5F EA
SENDDS: NOP
2371 EC60 A9 C7
RECVDS: LDA #$C7 iMASK OFF SERIAL BUS INTERRUPTS
2372 EC62 25 10 AND
POKMSK
2373 EC64 85 10 STA POKMSK
iSTORE NEW VALUE TO SYSTEM MASK
2374 EC66 8D OE D2 STA
IRQEN iSTORE TO ACTUAL REGISTER
2375
2376 EC69
A2 06 LDX
#6
2377
EC6B A9 00 LDA
#0
2378 EC6D 9D 01 D2
ZERIT:
STA
AUDC1,X
2379 EC70 CA DEX
2380 EC71 CA DEX
2381 EC72 10 F9 BPL ZERIT
iTURN OFF AUDIO VOLUME
2382