Hitachi H8/3035 Series Hardware Manual page 155

• Modes 1 and 2
Pins P8 to P8 function as input pins. Do not set P8
3 1
functions as an output pin when P8
cleared to 0.
• Mode 3
Port 8 is a generic input/output port. A pin port 8 becomes an output pin if the corresponding
P8DDR bit is set to 1, and an input pin if this bit is cleared to 0.
Bits 7 to 4 are reserved bits. P8DDR is a write-only register. Its value cannot be read. All bits
return 1 when read.
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 P8 to P8 .
3 0
Bit 7
—
Initial value 1
Read/Write —
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 4 are reserved. Bits 7 to 5 cannot be modified and always read 1. Bit 4 cannot be
modified and is always read as 0. If bit 4 of P8DDR is read while its value is 1, bit 4 of P8DR is
read directly. If bit 4 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.
DDR is set to 1, and as input pin when P8
0
6 5 4
— — —
1 1 0
— — —
Reserved bits
DDR to P8 DDR to 1. Pin P8
3 1
3 2
P8 P8 P8
3 2
0 0
R/W R/W R/W
Port 8 data 4 to 0
These bits store data
for port 8 pins
0
DDR is
0
1 0
P8
1 0
0 0
R/W
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