Mitsubishi DS907x SIP, DS5000TK manual 158

;End of program.

USER'S GUIDE

POP	DPH	;Restore	the data
POP	DPL	; pointer from stack.
RET		;Return.

;

;************************************

;*** SUBROUTINE TO WRITE A DATA BYTE ;************************************

;

;This subroutine performs a ªcontext switchº to the CE2 data

;space and then writes one byte from the accumulator to the

;timekeeping device. Then it switches back to the CE1 data

;space and returns with all registers unchanged.

;
WBYTE:	PUSH	DPL		;Save the	data
	PUSH	DPH		; pointer	on stack.
	PUSH	MCON		;Save the	MCON register.
	ORL	MCON,#4		;Switch to CE2.
	PUSH	B		;Save the	B register.
	MOV	DPH,#0		;Set high	address byte.
		MOV	B,	#8 ;Set the bit Count.
LO:	PUSH	ACC		;Save the accumulator.
	ANL	A, #1		;Set up bit for output.
	MOV	DPL,A		;Set address to write bit.
	MOVX	A, @DPTR		;Output the data bit.
	POP	ACC		;Restore the accumulator.
	RR	A		;Position	next bit.
	DJNZ	B, LO		;Loop for	a whole byte.
	POP	B		;Restore the B register.
	POP	MCON		;Restore the MCON register.
	POP	DPH		;Restore the data
	POP	DPL		; pointer	from stack.
	RET			;Return.

;

;****************

;END OF PROGRAM ;****************

END

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