
10 Input/Output Port (P)
10-2
Seiko Epson Corporation
S1C17601 TECHNICAL MANUAL
10.2 Input/Output Pin Function Selection (Port MUX)
The input/output port pins share peripheral module input/output pins (with certain exceptions). Each pin can be set
for use as an input/output port or for peripheral modules via the corresponding port function selection bits for each
port. Pins not used for peripheral modules can be used as general purpose input/output ports.
Table 10.2.1: Input/output pin function selection
Pin function 1
PxxMUX = 0
Pin function 1
PxxMUX = 01
Pin function 1
PxxMUX = 10
Pin function 1
PxxMUX = 11
Port function
selection bit
Control register
P00
RFCLKO(RFC)
LFRO(LCD)
P00MUX(D1-0)
P0 Port Function Select
(P0_PMUX) Register (0x52a0)
P01
TOUTN4(T16E)
P01MUX(D3-2)
P02/EXCL0(T16)
TOUT4(T16E)
P02MUX(D5-4)
P03
#ADTRG(ADC10SA)
P03MUX(D7-6)
P04/EXCL1(T16)
AIN3(ADC10SA)
P04MUX(D1-0)
P0 Port Function Select
(P0_PMUX) Register (0x52a1)
P05/EXCL2(T16)
AIN2(ADC10SA)
P05MUX(D3-2)
P06/EXCL3(T16E) AIN1(ADC10SA)
P06MUX(D5-4)
P07/EXCL4(T16E) AIN0(ADC10SA)
P07MUX(D7-6)
P10
SCL0(I2CM)
SCL1(I2CS)
P10MUX(D1-0)
P1 Port Function Select
(P1_PMUX) Register (0x52a2)
P11
SDA0(I2CM)
SDA1(I2CS)
P11MUX(D3-2)
P12
SENB(RFC)
#BFR(I2CS)
P12MUX(D5-4)
P13
SENA(RFC)
SDA1(I2CS)
P13MUX(D7-6)
P14
REF(RFC)
SCL1(I2CS)
P14MUX(D1-0)
P1 Port Function Select
(P1_PMUX) Register (0x52a3)
P15
RFIN(RFC)
P15MUX(D3-2)
P16
FOUT1(CLG)
P16MUX(D5-4)
P17
SPICLK(SPI)
SCLK(UART)
P17MUX(D7-6)
P20
SDO(SPI)
SOUT(UART)
P20MUX(D1-0)
P2 Port Function Select
(P2_PMUX) Register (0x52a4)
P21
SDI(SPI)
SIN(UART)
P21MUX(D3-2)
P22
#SPISS(SPI)
FOUTH(CLG)
P22MUX(D5-4)
P23
TOUT3(T16E)
SOUT(UART)
P23MUX(D7-6)
P24
TOUTN3(T16E)
SIN(UART)
TOUT5(T8OSC1)
P24MUX(D1-0)
P2 Port Function Select
(P2_PMUX) Register (0x52a5)
DSIO(DBG)
P25
P25MUX(D3-2)
DST2(DBG)
P26
P26MUX(D5-4)
DCLK(DBG)
P27
P27MUX(D7-6)
Resetting the input/output port pins (Pxx) resets them to their default functions (pin function 1 in Table 10.2.1).
P02, P04, P05, P06, P07 Pins can be used as external clock input pin of 16-bit timer by setting them to input mode.
But, when AIN is selected, P04 to P07 cannot be used as external clock of 16-bit timer.
For information on functions other than the input/output ports, refer to the discussion of the peripheral modules
indicated in parentheses. The sections below discuss port functions with the pins set as general purpose input/output
ports.