Hitachi H8/3937 Series Hardware Manual page 162

4. Port mode register 3 (PMR3)
Bit 7
—
Initial value 0
Read/Write —
PMR3 is an 8-bit read/write register, controlling the selection of pin functions for port 3 pins.
Upon reset, PMR3 is initialized to H'04.
Bits 7, 6, and 0: Reserved bits
These bits are reserved: they are always read as 0 and cannot be modified.
Bit 5: Watchdog timer source clock select (WDCKS)
This bit selects the watchdog timer source clock.
Bit 5
WDCKS Description
0 ø/8192 selected
1 øw/32 selected
Bit 4: TMIG noise canceler select (NCS)
This bit controls the noise canceler for the input capture input signal (TMIG).
Bit 4
NCS Description
0 Noise cancellation function not used
1 Noise cancellation function used
Bit 3: P4 /IRQ function switch (IRQ0)
3 0
This bit selects whether P4
Bit 3
IRQ0 Description
0 Functions as P4
Functions as IRQ
1
150
6 5
— WDCKS
0 0
— R/W
/IRQ is used as P4
3 0 3
input
3
input
0
4 3
NCS IRQ0 RESO
0 0
R/W R/W R/W
or as IRQ
.
0
2 1 0
UD —
1 0 0
R/W —
(initial value)
(initial value)
(initial value)