
7542 Group
Rev.3.02 Oct 31, 2006 Page 131 of 134
REJ03B0006-0302
Notes on Serial I/O1
1. I/O pin function when serial I/O1 is enabled.
The pin functions of P1
2
/S
CLK1
and P1
3
/S
RDY1
are switched to as
follows according to the setting values of a serial I/O1 mode selec-
tion bit (bit 6 of serial I/O1 control register (address 1A
16
)) and a
serial I/O1 synchronous clock selection bit (bit 1 of serial I/O1 con-
trol register).
(1) Serial I/O1 mode selection bit
→
“1” :
Clock synchronous type serial I/O is selected.
• Setup of a serial I/O1 synchronous clock selection bit
“0” : P1
2
pin turns into an output pin of a synchronous clock.
“1” : P1
2
pin turns into an input pin of a synchronous clock.
• Setup of a S
RDY1
output enable bit (SRDY)
“0” : P1
3
pin can be used as a normal I/O pin.
“1” : P1
3
pin turns into a S
RDY1
output pin.
(2) Serial I/O1 mode selection bit
→
“0” :
Clock asynchronous (UART) type serial I/O is selected.
• Setup of a serial I/O1 synchronous clock selection bit
“0”: P1
2
pin can be used as a normal I/O pin.
“1”: P1
2
pin turns into an input pin of an external clock.
• When clock asynchronous (UART) type serial I/O is selected, it
functions P1
3
pin. It can be used as a normal I/O pin.
Note on Bus Collision Detection
When serial I/O1 is operating at half-duplex communication, set
bus collision detection interrupt to be disabled.
Notes on Serial I/O2
1. I/O pin function when serial I/O2 is enabled
The pin functions of P0
6
/S
CLK2
and P0
7
/S
RDY2
are switched to as
follows according to the setting values of a serial I/O2 mode selec-
tion bit (bit 6 of serial I/O2 control register (address 30
16
)) and a
serial I/O2 synchronous clock selection bit (bit 2 of serial I/O2 con-
trol register).
(1) Serial I/O2 mode selection bit
→
“1” :
Clock synchronous type serial I/O is selected.
• Setup of a serial I/O2 synchronous clock selection bit
“0” : P0
6
pin turns into an output pin of a synchronous clock.
“1” : P0
6
pin turns into an input pin of a synchronous clock.
• Setup of a S
RDY2
output enable bit (SRDY)
“0” : P0
7
pin can be used as a normal I/O pin.
“1” : P0
7
pin turns into a S
RDY2
output pin.
(2) Serial I/O2 mode selection bit
→
“0” :
Clock asynchronous (UART) type serial I/O is selected.
• Setup of a serial I/O2 synchronous clock selection bit
“0”: P0
6
pin can be used as a normal I/O pin.
“1”: P0
6
pin turns into an input pin of an external clock.
• When clock asynchronous (UART) type serial I/O is selected, it
functions P0
7
pin. It can be used as a normal I/O pin.