M32C80 Datasheet, PDF (282/352 Pages) Renesas Technology Corp – 16/32-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M32C/80 SERIES

M32C/80 Group
22. Programmable I/O Ports
22.5 Function Select Register C (PSC and PSC3 Registers)
Figures 22.11 and 22.12 show the PSC and PSC3 registers.
When multiple peripheral function outputs are assigned to a pin, the PSC and PSC3 registers select which
peripheral function output is used.
Refer to 22.10 Analog Input and Other Peripheral Function Input for the PSC_7 bit in the PSC register.
22.6 Function Select Register D (PSD1 Register)
Figure 22.12 shows the PSD1 register.
When multiple peripheral function outputs are assigned to a pin, the PSD1 register selects which peripheral
function output is used.
22.7 Pull-up Control Register 0 to 3 (PUR0 to PUR3 Registers)
Figures 22.13 and 22.14 show the PUR0 to PUR3 registers.
The PUR0 to PUR3 registers select whether the ports, divided into groups of four ports, are pulled up or not.
Ports with bits in the PUR0 to PUR3 registers set to "1" (pull-up) and the direction registers set to "0" (input
mode) are pulled up.
Set bits in the PUR0 and PUR1 registers in ports P0 to P5, running as bus, to "0" (no pull-up) in memory
expansion mode and microprocessor mode. Ports P0, P1 and P40 to P43 can be pulled up when they are
used as input ports in memory expansion mode and microprocessor mode.
22.8 Port Control Register (PCR Register)
Figure 22.14 shows the PCR register.
The PCR register selects either CMOS output or N-channel open drain output as port P1 output format. If
the PCR0 bit is set to "1", N-channel open drain output is selected because the P-channel in the CMOS port
is turned off. This is, however, not a perfect open drain. Therefore, the absolute maximum rating of the
input voltage is between -0.3V and VCC2 + 0.3V.
If P1 is used as a port for data bus in memory expansion mode and microprocessor mode, set the PCR0 bit
to "0". If P1 is used as a port in memory expansion mode and microprocessor mode, the PCR0 bit deter-
mines the output format.
22.9 Analog Input and Other Peripheral Function Input
The PSL3_6 to PSL3_3 bits in the PSL3 register and the PSC_7 bit in the PSC register each separate
analog I/O ports from other peripheral functions. Setting the corresponding bit to "1" (analog I/O) to use the
analog I/O port (DA0, DA1, ANEX0, ANEX1, AN4 to AN7) prevents an intermediate potential from being
impressed to other peripheral functions. The impressed intermediate potential may cause increase in
power consumption.
Set the corresponding bit to "0" (except analog I/O) when analog I/O is not used. All peripheral function
inputs except the analog I/O port are available when the corresponding bit is set to "0". These inputs are
indeterminate when the bit is set to "1". When the PSC_7 bit is set to "1", key input interrupt request remains
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unchanged regardless of KI0 to KI3 pin input level change.
Rev. 1.00 Nov. 01, 2005 ^{Page 263} of 330
REJ09B0271-0100