7902 Group User’s Manual
12-41
SERIAL I/O
12.4 Clock asynchronous serial I/O (UART) mode
Fig. 12.4.4 Initial setting example for relevant registers when transmitting
(If the CTS function selected, transmission starts
when the CTSi pin’s input level becomes “L.”)
1
UART0 transmit/receive control register 1 (Address 3516)
UART1 transmit/receive control register 1 (Address 3D16)
b7
b0
Transmit enable bit
1: Transmission enabled
Transmission starts.
UART0 baud rate register (BRG0) (Address 3116)
UART1 baud rate register (BRG1) (Address 3916)
b7
b0
Can be set to “0016” to “FF16.”
UART0 transmit interrupt control register (Address 7116)
UART1 transmit interrupt control register (Address 7316)
b7
b0
Interrupt priority level select bits
When using interrupts, set these bits
to one of levels 1 to 7.
When disabling interrupts, set these
bits to level 0.
b7
b0
Transmit data is set.
b8
UART0 transmit buffer register (Addresses 3316, 3216)
UART1 transmit buffer register (Addresses 3B16, 3A16)
UART0 transmit/receive mode register (Address 3016)
UART1 transmit/receive mode register (Address 3816)
b7
b0
Internal/External clock select bit
0: Internal clock
1: External clock
1 0 0: UART mode (7 bits)
1 0 1: UART mode (8 bits)
1 1 0: UART mode (9 bits)
Stop bit length select bit
0: 1 stop bit
1: 2 stop bits
Odd/Even parity select bit
0: Odd parity
1: Even parity
Parity enable bit
0: Parity is disabled.
1: Parity is enabled.
Sleep select bit
0: Sleep mode cleared (invalid)
1: Sleep mode selected
1
b2 b1 b0
UART0 transmit/receive control register 0 (Address 3416)
UART1 transmit/receive control register 0 (Address 3C16)
b7
b0
BRG count source select bits
CTS/RTS function is select bit
0: CTS function selected
1: RTS function selected
0 0 : f2
0 1 : f16
1 0 : f64
1 1 : f512
b1 b0
b15
0
CTS/RTS enable bit
0: CTS/RTS function is enabled.
1: CTS/RTS function is disabled.
Note: The CLKi pin cannot be used when
the CTSi/RTSi separation is selected.
(Refer to “[Precaution for clock
asynchronous serial I/O (UART)
mode].”)
Serial I/O mode select bit
Serial I/O pin control register (Address AC16)
b7
b0
CTS0/RTS0 separate select bit
0: CTS0/RTS0 are used together.
1: CTS0/RTS0 are separated (Note).
CTS1/RTS1 separate select bit
0: CTS1/RTS1 are used together.
1: CTS1/RTS1 are separated (Note).
TxD0/P83 switch bit
0: Functions as TxD0.
TxD1/P87 switch bit
0: Functions as TxD1.
0
Port P8 direction register (Address 1416)
b7
b0
Pin CTS0
0
Pin CTS1
CTSi/RTSi are used together.
CTSi/RTSi are separated.