Task-Specific Program Code
C-8
C.3 Task-Specific Program Code
Example C–4. Implementing Simple Delay Loops (delay.asm)
* File:
delay.asm
*
* Function:
Delay loop. XF and I/O 3 pins toggle after each delay
*
.title ”Delay routine”
; 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
; Set zero wait states
out
60h, wsgr
splk
#0e00ch,60h
; Define iosr for bit I/O in aspcr
out
60h,aspcr
lar
ar0,#del
; Initialize ar0
mar
*,ar7
; Set ARP to ar7
splk
#0008h,6eh
; data for setting bit I/O 3
splk
#0000h,6fh
; data for clearing bit I/O 3
splk
#0ffffh,60h
; Inner repeat loop size
lar
ar7,#del
loop:
clrc
xf
; xf=0
out
6fh,iosr
; bit 3=0
dely1:
rpt
60h
; @ 50ns, this loop gives 3.4 ms approx.
nop
banz
dely1,ar7
; delay = 17*3.4 = 57.8 ms approx.
lar
ar7,#del
setc
xf
; xf=1
out
6eh,iosr
; bit 3=1
dely2:
rpt
60h
; @ 50ns, this loop gives 3.4 ms approx.
nop
banz
dely2,ar7
; delay = 17*3.4 = 57.8 ms approx.
lar
ar7,#del
b
loop
inpt1:
ret
; Unused interrupts
inpt23:
ret
; have dummy returns for safety
timer:
ret
uart:
ret
codtx:
ret
codrx:
ret
.end
; Assembler module end directive –optional
