M306H7MG-XXXFP Datasheet, PDF (252/329 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

M306H7MG-XXXFP/MC-XXXFP/FGFP
15. PROGRAMMABLE I/O PORTS
15. Programmable I/O Ports
The programmable input/output ports (hereafter referred to simply as “I/O ports”) consist of 79 lines P0 toP9 (except
P85). Each port can be set for input or output every line by using a direction register, and can also be chosen to be or
not be pulled high every 4 lines. P85 is an input-only port and does not have a pull-up resistor. Port P85 shares the pin
with NMI, so that the NMI input level can be read from the P8 register P8_5 bit.
Figures 15.1 to 15.5 show the I/O ports. Figure 15.6 shows the I/O pins.
Each pin functions as an I/O port, a peripheral function input/output.
For details on how to set peripheral functions, refer to each functional description in this manual. If any pin is used as
a peripheral function input, set the direction bit for that pin to “0” (input mode). Any pin used as an output pin for
peripheral functions is directed for output no matter how the corresponding direction bit is set.
15.1 Port Pi Direction Register (PDi Register, i = 0 to 9)
Figure 15.7 shows the direction registers.
This register selects whether the I/O port is to be used for input or output. The bits in this register correspond one
for one to each port.
No direction register bit for P85 is available.
15.2 Port Pi Register (Pi Register, i = 0 to 9)
Figure 15.8 show the Pi registers.
Data input/output to and from external devices are accomplished by reading and writing to the Pi register. The Pi
register consists of a port latch to hold the output data and a circuit to read the pin status. For ports set for input
mode, the input level of the pin can be read by reading the corresponding Pi register, and data can be written to the
port latch by writing to the Pi register.
For ports set for output mode, the port latch can be read by reading the corresponding Pi register, and data can be
written to the port latch by writing to the Pi register. The data written to the port latch is output from the pin. The
bits in the Pi register correspond one for one to each port.
15.3 Pull-up Control Register 0 to Pull-up Control Register 2 (PUR0 to PUR2
Registers)
Figure 15.9 shows the PUR0 to PUR2 registers.
The PUR0 to PUR2 register bits can be used to select whether or not to pull the corresponding port high in 4 bit
units. The port chosen to be pulled high has a pull-up resistor connected to it when the direction bit is set for input
mode.
15.4 Port Control Register
Figure 15.10 shows the port control register.
When the P1 register is read after setting the PCR register’s PCR0 bit to “1”, the corresponding port latch can be
read no matter how the PD1 register is set.
Rev.2.10 Oct 25, 2006 Page 252 of 326
REJ03B0152-0210