Updated code for EEPROM project

[Reborn121]

i am writing a program for an 8051...the program is suppose to erase device memory then read a value from variable EEADR and store in EEBYT and output the value to port 3...finally it is suppose to write a byte to EEPROM with address in EEADR and value in EEBYT...i am using the 8051 IDE to compile this and it compiles fine but i cant figure out how to actually check the routines and see if it is running properly...does anyone know how to check this for me or see any errors in the program? Also, since i am not reading anything from the EEPROM i did not put in any routine to read from it.
Thanks for any help!

SK equ p1.0		;serial clock
		DI equ p1.1		;data input
		DO equ p1.2		;data output
		CS equ p1.3		;chip select
		EEADR data 50h		;EEADR in 50h
		EEBYT data 60h		;EEBYT in 60h
		
		

	        DSEG AT 20H

		ORG     20H		; stack start
stack:		DS	20H		; stack length

		CSEG

		ORG	0000H		; start program in 0000H 
		jmp	start		; jump to start routine

		USING 0			; using register bank 0

start:
		clr	CS		; clear CS
		clr	SK		; clear serial clock
		setb	DI		; set data input
		setb	DO		; set data output

		mov EEADR, #55h		; move value 55h into EEADR
		mov EEBYT,EEADR         ;move EEADR to EEBYT
		mov p3,EEBYT            ;move EEBYT to port 3

		call ewen		; call enable write routine

		call eral		; call erase all routine

		call EWDS		; call disable writing routine

		mov  EEADR, #7fh	; address for byte
		mov  EEBYT, #45h	; byte value
		call write		; call write routine

;routine to enable write operations		
EWEN:
	
		setb	CS		; set chip select

		mov	dptr, #(10011b SHL 7)   ;shift left
		mov	b, #12		; move 12 into b
		call	send		; call send routine
		clr	CS		; clear chip select
		ret			; return
		
;routine to erase device
eral:
		setb	CS		; set chip select

		mov	dptr, #(10010b SHL 7)    ; shift left
		mov	b, #12		; move 12 into b
		call	send		; call send routine

		clr	CS		; clear chip select
		ret			; return
		
;routine to write a byte to EEPROM
write:
		setb	CS		; set chip select

		mov	dpl, #101b	; move 5 to dpl
		mov	b, #3		; move 3 to b
		call	send		; call send routine

		mov	dpl, EEADR	; move EEADR to dpl
		mov	b, #9	        ; number of bits
		call	send		; call send routine

		mov	dpl, EEBYT	; move EEBYT into dpl
		mov	b, #8		; move 8 into b
		call	send		; call send routine

		clr	CS		; clear chip select
		ret			; return

; routine to send data
send:
		push	b		; push b onto stack
		mov	a, b		; bit count into a
		clr	c		; clear bit c
		subb	a, #8		; subtract 8 from a
		jc      less1           ; jump if less than 8
		jz	equal		; jump if equals eight

		mov	b, a		; move a into b
		clr	c		; clear bit
		subb	a, #8		; subtract 8 from a
		jc	less2		; jump if less than eight
		jnz	great		; jump if greater than eight

		mov	a, dph		; move dph into a
		jmp	call		; jump to call

	less2:
		push	b		; push b onto stack
		mov	a, dph		; move dph into a
	shift:
		rr	a		; rotate a to right
		djnz	b, shift	; jump if b not zero to shift
		pop	b		; pop b from stack
	call:
		call	send2		; call send2 routine
		mov	b, #8		; move 8 into b

	equal:
		mov	a, dpl		; move dpl into a
		jmp	call2		; jump to call2

	less1:
		push	b		; push b onto stack
		mov	a, dpl		; move dpl into a
	shift2:
		rr	a		; rotate a to right
		djnz	b, shift2	; jump if b not zero to shift2
		pop	b		; pop b from stack
	call2:
		call	send2		; call send2 routine
	great:
		pop	b		;pop b from stack
		ret			;return

send2:
	out:
		clr	SK		; clear serial clock
		rlc	a		; move bit 
		mov	DI, c		; move c into data input
		nop			; delay min 400 nS
		setb	SK		; set serial clock
		djnz	b, out		; next bit / delay min one uS
		clr	SK		; clear clock
		ret			;return

ewds:
		setb	CS		; CS equals 1
		mov	dptr, #(10000b SHL 7)  
		mov	b, #12		;move 12 into b
		call	send		;call send routine

		clr	CS		; clear chip select
		ret			;return

Added after 17 minutes:

When i run the program after it runs through a couple times it gives me a "stack underflow" warning?
Also, any suggestions on how to stop the program once it runs the "call write" instruction?
Thanks

 

[srizbf]

it seems that there are many calls inside the subroutines.
a cause for stack underflow warning.

donot try to call many. rewrite the subs as short with minimum code , only allowing calls once if it cannot be avoided.

the subs should not call anything else.

srizbf
6thjuly2010

 

[Reborn121]

ok i fixed the "stack underflow" by putting this line at the beginning of the "start" routine

mov	sp, #(stack-1)	; initialize stack pointer

I also put this line after the "call write" instruction to stop the program

FIN:            sjmp fin		; halt program

is there anything else anybody notices? or can someone run this in a simulator and see if it works properly? Thank you for your post