M32C8A Datasheet, PDF (297/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
22. Programmable I/O Ports
22.6 Pull-up Control Register 0 to 4 (PUR0 to PUR4 Registers)
Figures 22.12 to 22.15 show registers PUR0 to PUR4.
Registers PUR0 to PUR4 select whether the ports, divided into groups of four, are pulled up or not. Set the bit in
registers PUR0 to PUR4 to 1 (pull-up) and the bit in the PDi register to 0 (input mode) to pull-up the corresponding
port.
In microprocessor mode, set bits, corresponding to the bus control pins (P0 to P5), in registers PUR0 and PUR1 to
0 (no pull-up). P1 can be pulled up when they are used as input ports in microprocessor mode.
22.7 Port Control Register (PCR Register)
Figure 22.16 shows the PCR register.
The PCR register selects either CMOS output or N-channel open drain output as port P1 output format. When the
PCR0 bit is set to 1, P channel in the CMOS port is turned off at all times and in result port P1 becomes N-channel
open drain output. This is, however, pseudo open drain. Therefore, the absolute maximum rating of the input
voltage is from -0.3 V to VCC2 + 0.3 V.
To use port P1 as data bus in microprocessor mode, set the PCR0 bit to 0 (CMOS output). When port P1 is used as
a port in microprocessor mode, set the output format using the PCR0 bit.
22.8 Analog Input and Other Peripheral Function Input
Bits PSL3_3 to PSL3_6 in the PSL3 register, and the PSC_7 bit in the PSC register separate peripheral function
inputs from analog input/output. If the analog I/O shares the pin with other peripheral function inputs, a through
current may flow to the peripheral function inputs when an intermediate voltage is applied to the pin.
To use the analog I/O (DA0, DA1, ANEX0, ANEX1, or AN_4 to AN_7), set the corresponding bit to 1 (analog I/
O), and disconnect the peripheral function inputs to prevent an intermediate voltage from being applied to the
peripheral function inputs.
Set the corresponding bit to 0 (except analog I/O) when analog I/O is not used. All the peripheral function inputs
except the analog I/O are enabled when the corresponding bit is set to 0, and undefined when the bit is set to 1.
When the PSC_7 bit is set to 1, the IR bit in the KUPIC register remains unchanged as 0 even if KI0 to KI3 pin
input levels are changed.
Rev.1.00 Jul 15, 2007 Page 280 of 352
REJ09B0385-0100