11 UART (UART3)
11-12
Seiko Epson Corporation
S1C17M12/M13 TECHNICAL MANUAL
(Rev. 1.2)
UART3 Ch.
n
Control Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UAnCTL
15–8 –
0x00
–
R
–
7–2 –
0x00
–
R
1
SFTRST
0
H0
R/W
0
MODEN
0
H0
R/W
Bits 15–2 Reserved
Bit 1
SFTRST
This bit issues software reset to the UART3.
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 UART3 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 UART3 operations.
1 (R/W): Enable UART3 operations (The operating clock is supplied.)
0 (R/W): Disable UART3 operations (The operating clock is stopped.)
Note
: If the
UAnCTL.MODEN bit is altered from 1 to 0 while sending/receiving data, the data being
sent/received cannot be guaranteed. When setting the UAnCTL.MODEN bit to 1 again after
that, be sure to write 1 to the UAnCTL.SFTRST bit as well.
UART3 Ch.
n
Transmit Data Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UAnTXD
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.
UART3 Ch.
n
Receive Data Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UAnRXD
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.