
327
When a PEDDR bit is cleared to 0 (input port setting), 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
previous state after a manual reset and in software standby mode.
9.11.3
Pin Functions in Each Mode
(1) Modes 4 to 6
In modes 4 to 6, if 8-bit access space is designated and 8-bit bus mode is selected, port E functions
as an I/O port. 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 settings in PEDDR are ignored, and
port E pins function as data input/output pins.
Port E pin functions in modes 4 to 6 are shown in figure 9-16.
PE7 (input/output)
PE6 (input/output)
PE5 (input/output)
PE4 (input/output)
PE3 (input/output)
PE2 (input/output)
PE1 (input/output)
PE0 (input/output)
D7 (input/output)
D6 (input/output)
D5 (input/output)
D4 (input/output)
D3 (input/output)
D2 (input/output)
D1 (input/output)
D0 (input/output)
8-bit bus mode
Port E
16-bit bus mode
Figure 9-16 Port E Pin Functions (Modes 4 to 6)