Task-Specific Program Code
C-19
Program Examples
Example C–12. Testing and Using Asynchronous Serial Port Delta Interrupts(bitio.asm)
(Continued)
uart: setc xf ; toggle xf bit
in 68h,iosr ; Bit i/o check
bit 68h,8 ; bit address 7 I/O 3 BIT IS SET?
; required bit place = complement 7 !
bcnd poll,ntc ; NO then check FOR I/O 2
clrc tc
out 65h, adtr ; transmit 63h =’c’
splk #0080h,6bh ; reset delta bit
out 6bh,iosr ; THE DELTA INTERRUPTS WILL BE ALWAYS
; COMING IF THIS IS NOT CLEARED!!!
clrc xf ; clear xf bit
splk #20h,ifr ; clear ifr bits
clrc intm
ret
poll: in 68h,iosr
bit 68h,9 ; bit address 6 I/O 2 bit is set?
bcnd poll1,ntc
clrc tc
out 67h, adtr ; if set transmit 69h = ’i’
splk #0040h,6bh ; reset delta bit
out 6bh,iosr
poll1: clrc xf ; clear xf bit
splk #20h,ifr ; clear ifr bits
clrc intm
ret
inpt1: ret
inpt23: ret
timer: ret
codtx: ret
codrx: ret
.end ; Assembler module end directive
; –optional
