13 UART (UART3)
13-14
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
UART3 Ch.
n
Transmit Data Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UART3_nTXD
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 UART3_
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
UART3_nRXD
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.
UART3 Ch.
n
Status and Interrupt Flag Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UART3_nINTF
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
UART3_nRXD 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 UART3_nRXD
register.
1
RB1FIF
0
H0/S0
R
0
TBEIF
1
H0/S0
R
Cleared by writing to the UART3_
nTXD register.
Bits 15–10 Reserved
Bit 9
RBSY
This bit indicates the receiving status. (See Figure 13.5.3.1.)
1 (R):
During receiving
0 (R):
Idle
Bit 8
TBSY
This bit indicates the sending status. (See Figure 13.5.2.1.)
1 (R):
During sending
0 (R):
Idle
Bit 7
Reserved