Mitsubishi DS5000TK Guida Utente Scaricare il pdf (Pagina 158)

USER’S GUIDE

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POP DPH ;Restore the data

POP DPL ; pointer from stack.

RET ;Return.

;

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

;*** SUBROUTINE TO WRITE A DATA BYTE

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

;

; This subroutine performs a “context switch” 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 ;End of program.

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Mitsubishi DS5000TK Guida Utente Pagina 158