Pin States; Mos Input Pull-Up - Hitachi H8/3937 Series Hardware Manual

8.4.4

Pin States

Table 8-10 shows the port 3 pin states in each operating mode.
Table 8-10 Port 3 Pin States
Pins Reset
P3 High-
7
P3 impedance
6
P3 /TXD
5 31
P3 /RXD
4 31
P3 /SCK
3 31
P3 /RESO Reset output
2
P3 /UD High-
1
P3 impedance
0
Note: A high-level signal is output when the MOS pull-up is in the on state.
*
8.4.5

MOS Input Pull-Up

Port 3 has a built-in MOS input pull-up function that can be controlled by software. When a
PCR3 bit is cleared to 0, setting the corresponding PUCR3 bit to 1 turns on the MOS pull-up for
that pin. The MOS pull-up function is in the off state after a reset.
PCR3
n
PUCR3
n
MOS input pull-up
Sleep Subsleep
Retains Retains
previous previous
state state
0
0
Off
Standby Watch
High- Retains
impedance* previous
state
0
1
On
Subactive Active
Functional Functional
1
*
Off
(n = 7 to 0)
*: Don't care
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