SERIAL I/O
11.3 Clock synchronous serial I/O mode
UART0 transmit/receive mode register (Address 3016
UART1 transmit/receive mode register (Address 3816
)
)
b7
b0
ꢀ
ꢀ ꢀ
0
0
0
1
Selection of clock synchronous serial
I/O mode
UART0 transmit interrupt control register (Address 7116
UART1 transmit interrupt control register (Address 7316
)
)
Internal/External clock select bit
0: Internal clock
b7
b0
1: External clock
Interrupt priority level select bits
When using interrupts, set these bits to
one of levels 1 to 7.
ꢀ: It may be either “0” or “1.”
When disabling interrupts, set these bits
to level 0.
UART0 transmit/receive control register 0 (Address 3416
UART1 transmit/receive control register 0 (Address 3C16
b7 b0
)
)
UART0 transmit buffer register (Address 3216
UART1 transmit buffer register (Address 3A16
b7 b0
)
)
BRG count source select bits
b1 b0
0 0 : f
2
0 1 : f16
1 0 : f64
1 1 : f512
Transmit data is set.
CTS
/
RTS function select bit
0: CTS function selected
1: RTS function selected
CTS/RTS enable bit
0: CTS
1: CTS
/
/
RTS function is enabled.
RTS function is disabled.
UART0 transmit/receive control register 1 (Address 3516
UART1 transmit/receive control register 1 (Address 3D16
)
)
CLK polarity select bit
b7
b0
0: At the falling edge of the transfer
clock, transmit data is output.
1: At the rising edge of the transfer
clock, transmit data is output.
1
Transmit enable bit
1: Transmission is enabled.
Transfer format select bit
0: LSB first
1: MSB first
Serial I/O pin control register (Address AC16
b7 b0
)
Transmission starts.
(In the case of selecting the CTS function, transmission
starts when the CTS0 pin’s input level is “L.”)
CTS
0: CTS
CTS /RTS
0: CTS /RTS
TxD /P1 switch bit
0: Functions as TxD
TxD /P1 switch bit
0: Functions as TxD
0
/RTS
0
separate select bit
0 are used together (Note).
0
/RTS
separate select bit
are used together (Note).
1
1
1
1
0
3
0
.
1
7
1
.
Note: In the clock synchronous serial I/O
mode, CTS/RTS separation cannot
i
i
be selected. (Refer to section “[Pre-
cautions for clock synchronous
serial I/O mode].”)
When extenal clock is selected
When internal clock is selected
UART0 baud rate register (BRG0) (Address 3116
UART1 baud rate register (BRG1) (Address 3916
)
)
b7
b0
Can be set to “0016” to “FF16.”
Fig. 11.3.2 Initial setting example for relevant registers when transmitting
7906 Group User’s Manual Rev.2.0
11-24
RENESAS [ RENESAS TECHNOLOGY CORP ]
