![](http://datasheet.mmic.net.cn/30000/M30280M8V-XXXHP_datasheet_2358818/M30280M8V-XXXHP_184.png)
14.Serial I/O
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UARTi Transmit/receive Control Rregister 0 (i=0 to 2)
Symbol
Address
After Reset
U0C0 to U2C0
03A416, 03AC16, 037C16
000010002
b7 b6 b5 b4 b3 b2 b1 b0
Function
TXEPT
CLK1
CLK0
CRS
CRD
NCH
CKPOL
BRG count source
select bit(7)
Transmit register empty
flag
0 : Transmit data is output at falling edge of transfer clock
and receive data is input at rising edge
1 : Transmit data is output at rising edge of transfer clock
and receive data is input at falling edge
CLK polarity select bit
CTS/RTS function
select bit
CTS/RTS disable bit
Data output select bit(5)
0 0 : f1SIO or f2SIO is selected
0 1 : f8SIO is selected
1 0 : f32SIO is selected
1 1 : Do not set
b1 b0
0 : LSB first
1 : MSB first
0 : Data present in transmit register (during transmission)
1 : No data present in transmit register
(transmission completed)
0 : CTS/RTS function enabled
1 : CTS/RTS function disabled
(P60, P64 and P73 can be used as I/O ports)(6)
0 : TxD2/SDA2 and SCLi pins are CMOS output
1 : TxD2/SDA2 and SCLi pins are N-channel open-drain output(4)
UFORM Transfer format select bit
(2)
Effective when CRD is set to 0
0 : CTS function is selected (1)
1 : RTS function is selected
Bit Name
Bit
Symbol
RW
RO
(3)
NOTES:
1. Set the corresponding port direction bit for each CTSi pin to 0 (input mode).
2. Effective when bits SMD2 to SMD0 in the UMR register to 0012 (clock synchronous serial I/O mode) or 0102 (UART mode transfer
data 8 bits long). Set the UFORM bit to 1 when bits SMD2 to SMD0 are set to 1012 (I2C bus mode) and 0 when they are set to 1002.
3. CTS1/RTS1 can be used when the CLKMD1 bit in the UCON register is set to 0 (only CLK1 output) and the RCSP bit in the UCON
register is set to 0 (CTS0/RTS0 not separated).
4. SDA2 and SCL2 are effective when i = 2.
5. When bits SMD2 to SMD in the UiMR regiser are set to 0002 (serial I/O disable), do not set NCH bit to 1 (TxDi/SDA2 and SCL2 pins
are N-channel open-drain output).
6. When the U1MAP bit in PACR register is 1 (P73 to P70), P70 functions as CTS/RTS pin in UART1.
7. When the CLK1 and CLK0 bit settings are changed, set the UiBRG register.
UART Transmit/receive Control Register 2
Symbol
Address
After Reset
UCON
03B016
X00000002
b7 b6 b5 b4 b3 b2 b1 b0
Bit Name
Bit
Symbol
RW
Function
CLKMD0
CLKMD1
Nothing is assigned. If necessary, set to 0.
When read, the content is undefined
U0IRS
U1IRS
U0RRM
U1RRM
RCSP
(b7)
RW
0 : Output from CLK1 only
1 : Transfer clock output from multiple pins function selected
Effective when the CLKMD1 bit is set to 1
0 : Clock output from CLK1
1 : Clock output from CLKS1
0 : Transmit buffer empty (Tl = 1)
1 : Transmission completed (TXEPT = 1)
0 : Transmit buffer empty (Tl = 1)
1 : Transmission completed (TXEPT = 1)
0 : Continuous receive mode disabled
1 : Continuous receive mode enable
0 : Continuous receive mode disabled
1 : Continuous receive mode enabled
UART1 transmit
interrupt cause select
UART0 continuous
receive mode enable bit
UART0 transmit interrupt
cause select bit
UART1 continuous
receive mode enable bit
UART1 CLK/CLKS
select bit 0
UART1 CLK/CLKS
select bit 1 (1)
Separate UART0
CTS/RTS bit
0 : CTS/RTS shared pin
1 : CTS/RTS separated (P64 pin functions as CTS0 pin )
(2)
NOTES:
1. When using multiple transfer clock output pins, make sure the following conditions are met:set the CKDIR bit in the U1MR
register to 0 (internal clock)
2. When the U1MAP bit in PACR register is set to 1 (P73 to P70), P70 pin functions as CTS0 pin.
Figure 14.6 U0C0 to U2C0 and UCON Registers