Echo2SIOInt.asm

Language: 8080 Assembly
Last Modified: 2022-11-15 1:50:54 AM UTC
File Size: 1055 bytes

http://www.penguinstew.ca/example/AltairSerialEcho/Echo2SIOInt.asm

; Read 2SIO status register

ORG 0000H

LXI SP, 0100H ; 0000: 31 00 01 Initalize stack pointer

MVI A, 03H ; 0003: 3E 03

OUT 10H ; 0005: D3 10 Rest 2SIO port

MVI A, 95H ; 0007: 3E 95

OUT 10H ; 0009: D3 10 Set 2SIO port to 8n1, enable 2SIO interupts

EI ; 000B: FB Enable CPU interupts

LOOP: NOP ; 000C: 00

NOP ; 000D: 00

NOP ; 000E: 00

JMP LOOP ; 000F: C3 0C 00 Program loop

ORG 0038H ; Interupt Handler

PUSH A ; 0038: F5 Save value of accumulator and PSW

IN 11H ; 0039: DB 11

OUT 11H ; 003B: D3 11 Echo value

POP A ; 003D: F1 Restore accumulator and PSW

EI ; 003E: FB Renable interupts

RET ; 003F: C9 return