UPD78F0138 NEC, UPD78F0138 Datasheet - Page 195

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

(3) Port mode registers 1 and 3 (PM1, PM3)
These registers set port 1 and 3 input/output in 1-bit units.
When using the P17/TO50/TI50 and P33/TO51/TI51/INTP4 pins for timer output, clear PM17 and PM33 and the
output latches of P17 and P33 to 0.
When using the P17/TO50/TI50 and P33/TO51/TI51/INTP4 pins for timer input, set PM17 and PM33 to 1. The
output latches of P17 and P33 at this time may be 0 or 1.
PM1 and PM3 can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets these registers to FFH.
Address: FF21H
Symbol
PM1
Address: FF23H
Symbol
PM3
PM17
PM1n
PM3n
7
0
1
7
0
0
1
After reset: FFH
After reset: FFH
Output mode (output buffer on)
Input mode (output buffer off)
Output mode (output buffer on)
Input mode (output buffer off)
PM16
CHAPTER 7 8-BIT TIMER/EVENT COUNTERS 50 AND 51
6
6
0
Figure 7-10. Format of Port Mode Register 3 (PM3)
Figure 7-9. Format of Port Mode Register 1 (PM1)
PM15
5
5
0
R/W
R/W
P1n pin I/O mode selection (n = 0 to 7)
P3n pin I/O mode selection (n = 0 to 3)
User’s Manual U16228EJ2V0UD
PM14
4
4
0
PM13
PM33
3
3
PM12
PM32
2
2
PM11
PM31
1
1
PM10
PM30
0
0
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