INPUT/OUTPUT PORTS AND PIN FUNCTIONS
8.3 Input/Output Port Related Registers
8
(3) PIEN0 (Port input enable) bit (Bit 15)
This bit is used to prevent current from flowing into the port input pins.
Because the input/output ports are disabled against input after reset, if any ports need to be used in input
mode they must be enabled for input by setting this bit to "1".
When disabled against input, the input/output ports are in a state equivalent to a situation where the pin has
a low-level input applied. Consequently, if a peripheral input function is selected for any port (uncontrolled
pin) while disabled against input by using the Port Operation Mode Register, the port may operate unexpect-
edly due to the low-level input on it.
The following shows the procedure for selecting a peripheral input function.
(1) Enable the port for input when its pin level is valid (high or low)
(2) Select a function using the port operation mode bit
During boot mode, the pins shared with serial I/O functions are enabled for input and can therefore be
protected against current flowing in from the pins other than serial I/O functions during flash programming by
clearing PIEN0.
The table below lists the pins that can be controlled by the PIEN0 bit in each operation mode.
Table 8.3.2 Pins Controllable by PIEN0 Bit
Mode Name
Controllable Pins
Uncontrolled Pins
P00–P07, P10–P17, P20–P27
P221, P223,
P30–P37, P41–P47, P61–P63
FP, MOD0, MOD1, SBI#, RESET#
Single-chip
P65–P67, P70–P77, P82–P87
P93–P97, P100–P107, P110–P117
P124–P127, P130–P137, P140–P147
P150–P157, P160–P167, P172–P177
P180–P187, P190–P197, P200–P203
P210–P217, P220–P222, P224–P227
P61–P63, P65–P67, P70–P77
P82–P87, P93–P97, P100–P107
P110–P117, P124–P127, P130–P137
P140–P147, P150–P157, P160–P167
P172–P177, P180–P187, P190–P197
P200–P203, P210–P217, P220
P222
P00–P07, P10–P17
P20–P27, P30–P37
P41–P47, P221, P223–P227
FP, MOD0, MOD1, SBI#, RESET#
External extension
Microprocessor
P00–P07, P10–P17, P20–P27
P30–P37, P41–P47, P61–P63
P67, P70–P77, P93–P97
P65, P66, P82–P87, P101
P135–P136, P174–P177, P200–P203
P221, P223,
Boot
(single-chip)
P100, P102–P107, P110–P117, P124–P127
P130–P134, P137, P140–P147, P150–P157
P160–P167, P172–P173, P180–P187
P190–P197, P210–P217, P220
FP, MOD0, MOD1, SBI#, RESET#
P222, P224–P227
32180 Group User’s Manual (Rev.1.0)
8-23
RENESAS [ RENESAS TECHNOLOGY CORP ]
