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RL78/D1A User's Manual: Hardware - Renesas

RL78/D1A User's Manual: Hardware - Renesas

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Under development<br />

Preliminary document<br />

Specifications in this document are tentative and subject to change.<br />

<strong>RL78</strong>/<strong>D1A</strong> CHAPTER 4 PORT FUNCTIONS<br />

4.2.4 Port 3<br />

Port 3 is an 8-bit I/O port with an output latch. Port 3 can be set to the input mode or output mode in 1-bit units using<br />

port mode register 3 (PM3). When the P30 to P37 pins are used as an input port, use of an on-chip pull-up resistor can be<br />

specified in 1-bit units by pull-up resistor option register 3 (PU3).<br />

Input to the P31 pin can be specified through a normal Schmitt3 input buffer or a Schmitt1 input buffer using port input<br />

mode register 3 (PIM3).<br />

Output from the P30 and P31 pins can be specified as normal CMOS output or N-ch open-drain output (VDD tolerance)<br />

in 1-bit units, using port output mode register (POM).<br />

These pins also function as timer I/O, serial interface data I/O, and segment signal outputs for the LCD controller/driver.<br />

To use P30 to P37 as the port function, refer Table 4-5.<br />

P30 to P37 Pins LCDPF3 Alternate function<br />

port function<br />

P30<br />

P31<br />

P32<br />

P33<br />

P34<br />

P35<br />

P36<br />

P37<br />

Table 4-5. Setting of P30 to P37 Pins to port function<br />

Register Timer Serial<br />

R01UH0317EJ0004 Rev. 0.04 161<br />

Feb. 22, 2013<br />

PM3<br />

Register<br />

PIM3<br />

Register<br />

POM<br />

Register<br />

Remarks<br />

Input port Digital I/O - - Input mode N/A<br />

-<br />

Output port<br />

selection<br />

0 1 Output mode<br />

0 CMOS output<br />

Input port Digital I/O<br />

selection<br />

- - Input mode<br />

Output port<br />

0 1 Output mode -<br />

Input port Digital I/O - - Input mode<br />

Output port<br />

selection<br />

0 1 Output mode<br />

Input port Digital I/O - N/A Input mode<br />

Output port<br />

selection<br />

0<br />

Output mode<br />

Input port Digital I/O - - Input mode<br />

Output port<br />

selection<br />

0 1 Output mode<br />

Input port Digital I/O - N/A Input mode<br />

Output port<br />

selection<br />

0<br />

Output mode<br />

Input port Digital I/O - N/A Input mode<br />

Output port<br />

selection<br />

0<br />

Output mode<br />

Input port Digital I/O - N/A Input mode<br />

Output port<br />

selection<br />

0<br />

Output mode<br />

- - LCD<br />

Segment<br />

output<br />

selection<br />

Reset signal generation sets port 3 to input mode.<br />

Figures 4-13 to 4-16 show block diagrams of port3.<br />

1 N-ch OD output<br />

0 Schmitt1 input<br />

1<br />

N/A N/A<br />

N/A N/A<br />

N/A N/A<br />

N/A N/A<br />

N/A N/A<br />

N/A N/A<br />

Schmitt3 input<br />

0 CMOS output<br />

1 N-ch OD output<br />

- - - - - LCD segment<br />

output

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