Hitachi H8S/2646 Hardware Manual page 276

Port 3 Register (PORT3)
Bit 7
P37
Initial value —*
Read/Write R
Note: * Determined by the state of pins P37 to P30.
PORT3 is an 8-bit read-dedicated register, which reflects the state of pins. Write is disenabled.
Always carry out writing off output data of port 3 pins (P37 to P30) to P3DR without fail.
When P3DDR is set to 1, if port 3 is read, the values of P3DR are read. When P3DDR is cleared to
0, if port 3 is read, the states of pins are read out.
P3DDR and P3DR are initialized by a reset and in hardware standby mode, so PORT3 is
determined by the state of the pins. The previous state is maintained in software standby mode.
Port 3 Open Drain Control Register (P3ODR)
Bit 7
P37ODR
Initial value 0
Read/Write R/W
P3ODR is an 8-bit readable/writable register, which controls the on/off of port 3 pins (P37 to P30).
By setting P3ODR to 1, the port 3 pins become an open drain output, and when cleared to 0 they
become CMOS output.
P3ODR is initialized to H'00 by a reset and in hardware standby mode. The previous state is
maintained in software standby mode.
244
6 5
P36 P35
—* —*
R R
6 5
P36ODR P35ODR P34ODR
0 0
R/W R/W
4 3
P34 P33
—* —*
R R
4 3
P33ODR P32ODR
0 0
R/W R/W R/W
2 1
P32 P31 P30
—* —*
R R
2 1
P31ODR P30ODR
0 0
R/W R/W
0
—*
R
0
0