Atari 400 Technical Reference Manual page 318

ERR LINE ADDR B1 B2 B3 B4 SIO ( SERIAL BUS INPUT/OUTPUT CONTROLLER ) PAGE 57
2545
2546
2547
2548
2549
2550
2551
2552 INITIAL BAUD RATE MEASUREMENT -- USED TO SET THE
2553 BAUD RATE AT THE START OF A RECORD.
2554
2555 IT IS ASSUMED THAT THE FIRST TWO BYTES OF EVERY
2556 RECORD ARE 'AA' HEX.
2557
2558 ED10 A5 11 BEGIN: LDA BRKKEY
2559 ED12 DO 03 BNE NTBRK2
2560 ED14 4C AO ED JMP BROKE iJUMP IF BREAK KEY PRESSED
2561
2562 ED17 78 NTBRK2: SEI
2563
2564 ED18 AD 17 03 LDA TIMFLG
2565 ED1B DO 02 BNE OKTIMl
iBRANCH IF NOT TIMED OUT
2566 ED1D FO 25 BEG TOUT1 iBRANCH IF TIME OUT
2567
2568 ED1F AD OF D2 OKTIM1 : LDA SKSTAT
2569 ED22 29 10 AND #$10 iREAD SERIAL PORT
2570 ED24 DO EA BNE BEGIN iSTART BIT?
2571 ED26 8D 16 03
STA
SAVIO
i
SAVE SER. DATA IN
2572 ED29 AE OB D4
LDX
VCOUNT iREAD VERTICAL LINE COUNTER
2573
ED2C A4 14 LDY
RTCLOK+2 iREAD La BYTE OF VBLANK CLOCK
2574 ED2E 8E OC 03 STX TIMER1
2575 ED31 8C OD 03 STY
TIMER1+1 iSAVE INITIAL TIMER VALUE
2576
2577 ED34
A2 01 LDX
#1 iSET MODE FLAG
2578 ED36 8E 15 03 STX TEMP3
2579 ED39 AO OA LDY #10
iSET BIT COUNTER FOR 10 BITS
2580 ED3B AS 11 COUNT: LDA BRKKEY
2581 ED3D FO 61 BEG BROKE
iBRANCH IF BREAK KEY PRESSED
2582
2583 ED3F AD 17 03 LDA TIMFLG
2584 ED42 DO 04 BNE OKTIMR iBRANCH IF NOT TIMED OUT
2585 ED44 58 TOUT1 : CLI
2586 ED45 4C OA EB JMP TOUT iBRANCH IF TIME OUT
2587
2588 ED48 AD OF D2 OKTIMR: LDA SKSTAT
2589 ED4B 29 10 AND
#$10 iREAD SERIAL PORT
2590 ED4D CD 16 03 CMP SAVIO
iDATA IN CHANGED YET?
2591 ED50 FO E9 BEG COUNT
2592 ED52 8D 16 03 STA SAVIO
i
YES, SAVE SER. DATA IN
2593 ED55 88 DEY ; DECR. BIT COUNTER
2594 ED56 DO E3 BNE COUNT
i
DONE?
2595
2596 ED 58 CE 15 03 DEC TEMP3
i
YES,
2597 ED5B 30 12 BMI GOREAD iDONE WITH BOTH MODES?
2598 ED 50 AD OB 04 LOA VCOUNT