H8SLASH3021 datasheet(184/712 Pages) RENESAS

184 / 712 page

7. I/O Ports

Rev.2.00 Mar. 22, 2007 Page 160 of 684

REJ09B0352-0200

Port 8 Data Direction Register (P8DDR): P8DDR is an 8-bit write-only register that can select

input or output for each pin in port 8.

—

P8 DDR

Reserved bits

Port 8 data direction 1 and 0

These bits select input or

output for port 8 pins

Bit

Initial value

Read/Write

P8DDR is initialized to H'E0 by a reset and in hardware standby mode. In software standby mode

it retains its previous setting. If a P8DDR bit is set to 1, the corresponding pin maintains its output

state in software standby mode.

Port 8 Data Register (P8DR): P8DR is an 8-bit readable/writable register that stores data for pins

1 to P80.

Bit

Initial value

Read/Write

—

R/W

—

R/W

—

R/W

Reserved bits

Port 8 data 1 and 0

These bits store data

for port 8 pins

When a bit in P8DDR is set to 1, if port 8 is read the value of the corresponding P8DR bit is

returned directly. When a bit in P8DDR is cleared to 0, if port 8 is read the corresponding pin level

is read.

Bits 7 to 2 are reserved. Bits 7 to 5 cannot be modified and always read 1. Bit 4, 3, and 2 can be

written and read, but it cannot be used for port input or output. If bit 4, 3, and 2 of P8DDR is read

while its value is 1, bit 4, 3 and 2 of P8DR is read directly. If bit 4, 3, and 2 of P8DDR is read

while its value is 0, it always reads 1.

P8DR is initialized to H'E0 by a reset and in hardware standby mode. In software standby mode it

retains its previous setting.

H8/3021 Datasheet(PDF) 184 Page - Renesas Technology Corp