
7542 Group
Rev.3.02 Oct 31, 2006 Page 51 of 134
REJ03B0006-0302
Fig. 60 Block diagram of clock synchronous serial I/O2
Fig. 61 Operation of clock synchronous serial I/O2 function
●
Serial I/O2
Serial I/O2 can be used as either clock synchronous or asynchro-
nous (UART) serial I/O. A dedicated timer is also provided for
baud rate generation.
(1) Clock Synchronous Serial I/O2 Mode
Clock synchronous serial I/O2 mode can be selected by setting
the serial I/O2 mode selection bit of the serial I/O2 control register
(bit 6) to “1”.
For clock synchronous serial I/O2, the transmitter and the receiver
must use the same clock. If an internal clock is used, transfer is
started by a write signal to the TB/RB.
D
7
D
7
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
0
D
1
D
2
D
3
D
4
D
5
D
6
RBF = 1
TSC = 1
TBE = 0
TBE = 1
TSC = 0
Transfer shift clock
(1/2 to 1/2048 of the internal
clock, or an external clock)
Serial output TxD
2
Serial input RxD
2
Write pulse to receive/transmit
buffer register 2 (address 002E
16
)
Overrun error (OE)
detection
Notes 1: As the transmit interrupt (TI), which can be selected, either when the transmit buffer has emptied (TBE=1) or after
the transmit shift operation has ended (TSC=1), by setting the transmit interrupt source selection bit (TIC) of the
serial I/O2 control register.
2: If data is written to the transmit buffer register when TSC=0, the transmit clock is generated continuously and serial
data is output continuously from the TxD
2
pin.
3: The receive interrupt (RI) is set when the receive buffer full flag (RBF) becomes “1” .
Receive enable signal
S
RDY2
1
/
4
1
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4
F
/
F
P
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0
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T
X
D
2
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