12/17

FIELD UPDATES FOR FLASH BASED ST7 APPLICATIONS USING A PC COMM PORT

; reads two successive characters from the character stream (hex-ascii)

; and returns them in a as a byte

getbinary:

call getdigit

swap a

ld b0byte0,a

call getdigit

add a,b0byte0

ret

; this subroutine gets copied to and is executed out of RAM

FLASHPROGRAMMER:

clr x

latchenable:

bset

FCSR,#1

; enable Xflash latches

fp004:

cp x,bytecount

jreq fp005

ld a,(flashbuffer,x)

ld ([loadaddress.w],x),a

inc x

ld a,x

add a,{loadaddress+1}

and a,#$1F

jrne fp004

; apply programming pulse

bset FCSR,#0

; set PGM

fp006:

btjt FCSR,#0,fp006

jrt latchenable

fp005:

; apply programming pulse

bset FCSR,#0

; set PGM

fp007:

btjt FCSR,#0,fp007

nop

nop

ret

; receives a hex-ascii character and converts to binary

getdigit:

call waitforchar

sub a,#48

cp a,#9

jrule getdigitA