UPD784938 Datasheet, PDF (131/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 6 PORT FUNCTIONS
6.3.2 I/O mode/control mode setting
The port 1 input/output mode is set for each pin by means of the port 1 mode register (PM1) as shown in Figure 6-13.
In addition to their input/output port function, P12 to P14 also have an alternate function as serial interface pins, and the
control mode is specified by setting the port 1 mode control register (PMC1) as shown in Figure 6-14.
Figure 6-13. Port 1 Mode Register (PM1) Format
PM1
7
6
5
4
3
2
1
0 Address After reset R/W
PM17 PM16 PM15 PM14 PM13 PM12 PM11 PM10 0FF21H
FFH
R/W
PM1n P1n Pin Input/Output Mode Specification
(n = 0 to 7)
0 Output mode (output buffer on)
1 Intput mode (output buffer off)
Figure 6-14. Port 1 Mode Control Register (PMC1) Format
7
6
5
4
3
2
1
0 Address After reset R/W
PMC1 0
0
0 PMC14 PMC13 PMC12 0
0 0FF41H
00H
R/W
PMC12 P12 Pin Control Mode Specification
0 Input/output port mode
1 ASCK2/SCK2 input/output mode
PMC13 P13 Pin Control Mode Specification
0 Input/output port mode
1 RxD2/SI2 input mode
PMC14 P14 Pin Control Mode Specification
0 Input/output port mode
1 TxD2/SO2 output mode
Preliminary User’s Manual U13987EJ1V0UM00
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