Table of Contents
Advertisement
Address
7
6
5
FDCH
–
PO6
–
The timing for switching of pull-up resistor presence/ absence by the setting of the pull-up resistor specification
register (POGA) is shown in Fig. 5-8.
Instruction
Execution
POGA
Remarks
through
are internal operation timing clock pulses.
o
3
After pull-up resistor incorporation has been specified by overwriting POGA, in consideration of the external load
capacity the pin level should be stabilized by execution of an NOP instruction etc. before an input/output instruction
is executed.
Example
To perform input after specifying incorporation of a pull-up resistor in port 1.
MOV
MOV
IN
52
CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
Fig. 5-7 Format of Pull-Up Resistor Specification Register
4
3
2
1
–
PO3
PO2
PO1
PO0
0
Pull-up resistor not incorporated
1
Pull-up resistor incorporated
Fig. 5-8 Pull-Up Resistor Incorporation Switching Timing
2-Machine Cycles
Manipulation Instruction
XA, #02H
POGA, XA
A, PORT1
0
Symbol
POGA
Port 0 (P01 to P03)
Port 1 (P12)
Port 2 (P20 to P23)
Port 3 (P30 to P33)
Port 6 (P60 to P63)
Specification
3
; Pull-up resistor incorporated in port 1
Wait until pin level is stabilized in consideration of
external load capacity.
0
1
Advertisement
Table of Contents
