Technical information

2-37
3800 GROUP USER’S MANUAL
APPLICATION
2.3 Serial I/O
Figure 2.3.21 shows a setting of serial I/O related registers, and Figure 2.3.22 shows a setting of serial
I/O transmission data.
Fig. 2.3.22 Setting of serial I/O transmission data [Output of serial data]
Fig. 2.3.21 Setting of serial I/O related registers [Output of serial data]
Set a transmission data.
Check that transmission of the previous data is
completed before writing data (bit 3 of the
Interrupt request register 1 is set to “1”).
TB/RB
Transmit/Receive buffer register (Address : 18
16)
b7 b0
Serial I/O synchronous clock selection bit : BRG/4
S RDY output enable bit : Not use the S RDY signal output function
0
Serial I/O transmit interrupt enable bit : Interrupt disabled
ICON1
Interrupt control register 1 (Address : 3E
16 )
Serial I/O transmit interrupt request bit
Using this bit, check the completion of
transmitting 1-byte base data.
“1” : Transmit shift completion
IREQ1
Interrupt request register 1 (Address : 3C
16 )
001
SIOCON
Serial I/O control register (Address : 1A
16 )
0011
BRG count source selection bit : f(X IN )
Transmit interrupt source selection bit : Transmit shift operating completion 
Transmit enable bit : Transmit enabled
1
Receive enable bit : Receive disabled
b7 b0
0
b7 b0
b7 b0
Serial I/O mode selection bit : Clock synchronous serial I/O
Serial I/O enable bit : Serial I/O enabled
0
P4 5 /T X D P-channel output disable bit : CMOS output
UARTCON
UART control register (Address : 1B
16 )
b7 b0
7
Set “division ratio – 1”
BRG
Baud rate generator (Address : 1C
16 )
b7 b0