Datasheet
CHAPTER 13 SERIAL INTERFACE UART0
User’s Manual U18698EJ1V0UD
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(5) Port mode register 1 (PM1)
This register sets port 1 input/output in 1-bit units.
When using the P13/TxD0/KR4/<TxD6> pin for serial interface data output, clear PM13 to 0. The output latch of
P13 at this time may be 0 or 1.
When using the P12/RxD0/KR3/<RxD6> pin for serial interface data input, set PM12 to 1. The output latch of
P12 at this time may be 0 or 1.
PM1 can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation sets this register to FFH.
Remark The functions within arrowheads (< >) can be assigned by setting the input switch control register (ISC).
Figure 13-6. Format of Port Mode Register 1 (PM1)
Address: FF21H After reset: FFH R/W
Symbol 7 6 5 4 3 2 1 0
PM1 1 1 1 1 PM13 PM12 1 1
PM1n P1n pin I/O mode selection (n = 2, 3)
0 Output mode (output buffer on)
1 Input mode (output buffer off)