Programming Notes - Epson S1C6S3N2 Technical Manual

CHAPTER 5: PERIPHERAL CIRCUITS (I/O Ports)
Program
YDTB
;
;

Programming notes

II-86
EQU H
LD X,7EH
OR MX,0001B
LD X,7DH
LD MX,A
LD X,0FEH
OR MX,0001B
LD X,7DH
LD Y,YDTB
LD MX,MY
(1) When the I/O port is being read out and the pull-down is
executed only with the built-in pull-down resistor of the
I/O ports, the read-out must be repeated about ten times
when the CPU is operating with the OSC3 oscillation
circuit.
(2) When the I/O port is set to the output mode and the data
register has been read, the pin data instead of the regis-
ter data can be read out. Because of this, if a low-imped-
ance load is connected and read-out performed, the value
of the register and the read-out result may differ.
EPSON
; Data buffer address
; Set the ports P00–P03 to output mode
;
; Output the value of A register to P00–P03
;
; Set the ports P10–P13 to output mode
;
; Output the value of RAM, YDTB to P10–P13
;
;
S1C6S3N2 TECHNICAL SOFTWARE