Task-Specific Program Code
C-9
Program Examples
Example C–5. Testing and Using the Timer (timer.asm)
* File:
timer.asm
*
* Function: Timer test code
*
* PRD=0x00ff,TDDR=f @ 50ns, gives an interrupt interval=205us
*
* PRD=0xffff,TDDR=0 @ 50ns, gives an interrupt interval=3.27ms*
* Timer interval measurable on I/O 2,3 or xf pins
*
.title ”Timer Test”
; Title
.copy
”init.h”
; Variable and register declaration
.copy
”vector.h”
; Vector label declaration
.text
start:
clrc
CNF
; Map block B0 to data memory
ldp
#0h
; set DP=0
setc
INTM
; Disable all interrupts
splk
#0000h,60h
out
60h, wsgr
; Set zero wait states
splk
#0ffffh,ifr
; clear interrupts
splk
#0004h,imr
; enable timer interrupt
splk
#0e00ch, 60h
; configure bit I/O I03 and IO2 as outputs
out
60h, aspcr
; set the aspcr for the above
mar
*,ar1
lar
ar1,#rxbuf
splk
#0004h,61h
; bit value to set I/O 2
splk
#0008h,62h
; bit value to set I/O 3
out
61h,iosr
; set the bit 2 = high, 3= zero
splk
#0000h, 63h
splk
#00ffh, 64h
out
64h, prd
; set PRD=0x00ffh
out
63h, tim
; set TIM=0x0000
splk
#0c2fh, 64h
; PSC, TDDR are zero, reload, restart
out
64h, tcr
clrc
intm
clrc
xf
wait:
out
62h,iosr
; set io2=0
idle
clrc
xf
b
wait
timer:
setc
xf
; xf =1
in
68h,tcr
; Read tcr,prd, tim regs.
in
69h,prd
in
6ah,tim
out
61h,iosr
; set io2=1
clrc
intm
ret
inpt1:
ret
; Unused interrupt routines
inpt23:
ret
codtx:
ret
codrx:
ret
uart:
ret
.end
; Assembler module end directive –optional
