10 UART (UART)
S1C17F13 TeChniCal Manual
Seiko epson Corporation
10-11
(Rev. 1.0)
Bit 1
SFTRST
This bit issues software reset to the UART.
1 (W):
Issue software reset
0 (W):
Ineffective
1 (R):
Software reset is executing.
0 (R):
Software reset has finished. (During normal operation)
Setting this bit resets the UART transmit/receive control circuit and interrupt flags. This bit is auto-
matically cleared after the reset processing has finished.
Bit 0
MODen
This bit enables the UART operations.
1 (R/W): Enable UART operations (The operating clock is supplied.)
0 (R/W): Disable UART operations (The operating clock is stopped.)
Note
: If the
UA
n
CTL.MODEN bit is altered from 1 to 0 during sending/receiving data, the data be-
ing sent/received cannot be guaranteed. When setting the UA
n
CTL.MODEN bit to 1 again
after that, be sure to write 1 to the UA
n
CTL.SFTRST bit as well.
uaRT Ch.
n
Transmit Data Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UA
n
TXD
15–8 –
0x00
–
R
–
7–0 TXD[7:0]
0x00
H0
R/W
Bits 15–8 Reserved
Bits 7–0
TXD[7:0]
Data can be written to the transmit data buffer through these bits. Make sure the UA
n
INTF.TBEIF bit
is set to 1 before writing data.
uaRT Ch.
n
Receive Data Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UA
n
RXD
15–8 –
0x00
–
R
–
7–0 RXD[7:0]
0x00
H0
R
Bits 15–8 Reserved
Bits 7–0
RXD[7:0]
The receive data buffer can be read through these bits. The receive data buffer consists of a 2-byte
FIFO, and older received data is read first.
uaRT Ch.
n
Status and interrupt Flag Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UA
n
INTF
15–10 –
0x00
–
R
–
9
RBSY
0
H0/S0
R
8
TBSY
0
H0/S0
R
7
–
0
–
R
6
TENDIF
0
H0/S0
R/W Cleared by writing 1.
5
FEIF
0
H0/S0
R/W Cleared by writing 1 or reading the
UA
n
RXD register.
4
PEIF
0
H0/S0
R/W
3
OEIF
0
H0/S0
R/W Cleared by writing 1.
2
RB2FIF
0
H0/S0
R
Cleared by reading the UA
n
RXD reg-
ister.
1
RB1FIF
0
H0/S0
R
0
TBEIF
1
H0/S0
R
Cleared by writing to the UA
n
TXD
register.
Bits 15–10 Reserved