
7-25
MSM64164C User's Manual
Chapter 7 Ports (P0, P1, P2, P3 and P4)
7
Bit 2: SIN (P33CON)
This bit selects data input (SIN) of the serial port which is a secondary function of Port
3.3. When SIN is reset to "0", P3.3 becomes a normal port function and when SIN is set
to "1", the data input function of the serial port is assigned. When SIN is set to "1", P3.3 is
automatically set to input mode. At system reset, SIN is reset to "0".
Bit 2: SOUT (P40CON)
This bit sets data output (SOUT) of the serial port which is a secondary function of Port
4.0. When SOUT is reset to "0", P4.0 becomes a normal port function and when it is set
to "1", the data output function of the serial port is assigned. When SOUT is set to "1",
P4.0 is set to output mode automatically. At system reset, SOUT is reset to "0".
Bit 2: SPR (P41CON)
This bit sets data ready signal (SPR) of the serial port which is a secondary function of
Port 4.1. When SPR is reset to "0", P4.1 becomes a normal port function and when it is
set to "1", the data ready signal output function of the serial port is assigned. When SPR
is set to "1", P4.1 is set to output mode automatically. At system reset, SPR is reset to
"0".
Bit 2: SCLK (P42CON)
This bit sets transfer clock input/output (SCLK) of the serial port which is a secondary
function of Port 4.2. When SCLK is reset to "0", P4.2 becomes a normal port function and
when it is set to "1", the transfer clock input/output function of the serial port is assigned.
When SCLK is set to "1", P4.2 is set to output mode automatically in the mode where the
system clock is set as the transfer clock after resetting the EXSC bit of the serial port
control register (SCON) to "0". P4.2 is set to input mode in the mode where the EXSC bit
is set to "1". At system reset, SCLK is reset to "0".
Bit 2: MON (P43CON)
This bit sets output of the RC oscillation clock (MON) which is a secondary function of
Port 4.3. When MON is reset to "0", P4.3 becomes a normal port function and when it is
set to "1", the output function of the A/D converter RC oscillation clock is assigned. When
MON is set to "1", P4.3 is set to output mode automatically. At system reset, MON is
reset to "0".
Bit 1: P20DIR to P23DIR, P30DIR to P33DIR and P40DIR to P43DIR
This bit selects input/output of each port. When each DIR bit is reset to "0", each port
becomes input mode and when each DIR bit is set to "1", each port becomes output
mode. At system reset, each DIR bit is reset to "0".
Bit 0: P20MOD to P23MOD, P30MOD to P33MOD and P40MOD to P43MOD
When each DIR bit is reset to "0" to select input mode, pull-down/pull-up resistance input
or high-impedance input is selected.