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Port E MOS Pull-Up Control Register (PEPCR)
Bit
:
PE7PCR PE6PCR PE5PCR PE4PCR PE3PCR PE2PCR PE1PCR PE0PCR
Initial value :
R/W
:
R/W
PEPCR is an 8-bit readable/writable register that controls the MOS input pull-up function
incorporated into port E on an individual bit basis.
When a PEDDR bit is cleared to 0 (input port setting) with 8-bit bus mode selected in mode 4, 5,
or 6, or in mode 7, setting the corresponding PEPCR bit to 1 turns on the MOS input pull-up for
the corresponding pin.
PEPCR is initialized to H'00 by a power-on reset, and in hardware standby mode. It retains its
prior state by a manual reset or in software standby mode.
10.11.3 Pin Functions
Modes 4 to 6: In modes 4 to 6, when 8-bit access is designated and 8-bit bus mode is selected,
port E pins are automatically designated as I/O ports. Setting a PEDDR bit to 1 makes the
corresponding port E pin an output port, while clearing the bit to 0 makes the pin an input port.
When 16-bit bus mode is selected, the input/output direction specification by PEDDR is ignored,
and port E is designated for data I/O.
Port E pin functions in modes 4 to 6 are shown in figure 10-20.
390
7
6
0
0
R/W
R/W
8-bit bus mode
PE7
PE6
PE5
PE4
Port E
PE3
PE2
PE1
PE0
Figure 10-20 Port E Pin Functions (Modes 4 to 6)
5
4
0
0
R/W
(I/O)
(I/O)
(I/O)
(I/O)
(I/O)
(I/O)
(I/O)
(I/O)
3
2
0
0
R/W
R/W
16-bit bus mode
D7
(I/O)
D6
(I/O)
D5
(I/O)
D4
(I/O)
D3
(I/O)
D2
(I/O)
D1
(I/O)
D0
(I/O)
1
0
0
0
R/W
R/W
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