13 UART (UART3)
S1C31D50/D51 TECHNICAL MANUAL
Seiko Epson Corporation
13-11
(Rev. 2.00)
13.9 Control Registers
UART3 Ch.
n
Clock Control Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UART3_nCLK
15–9 –
0x00
–
R
–
8
DBRUN
0
H0
R/W
7–6 –
0x0
–
R
5–4 CLKDIV[1:0]
0x0
H0
R/W
3–2 –
0x0
–
R
1–0 CLKSRC[1:0]
0x0
H0
R/W
Bits 15–9 Reserved
Bit 8
DBRUN
This bit sets whether the UART3 operating clock is supplied in DEBUG mode or not.
1 (R/W): Clock supplied in DEBUG mode
0 (R/W): No clock supplied in DEBUG mode
Bits 7–6
Reserved
Bits 5–4
CLKDIV[1:0]
These bits select the division ratio of the UART3 operating clock.
Bits 3–2
Reserved
Bits 1–0
CLKSRC[1:0]
These bits select the clock source of the UART3.
Table 13.9.1 Clock Source and Division Ratio Settings
UART3_nCLK.
CLKDIV[1:0] bits
UART3_nCLK.CLKSRC[1:0] bits
0x0
0x1
0x2
0x3
IOSC
OSC1
OSC3
EXOSC
0x3
1/8
1/1
1/8
1/1
0x2
1/4
1/4
0x1
1/2
1/2
0x0
1/1
1/1
(Note) The oscillation circuits/external input that are not supported in this IC cannot be
selected as the clock source.
Note: The UART3_nCLK register settings can be altered only when the UART3_nCTL.MODEN bit = 0.
UART3 Ch.
n
Mode Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
UART3_nMOD
15–13 –
0x0
–
R
–
12 PECAR
0
H0
R/W
11 CAREN
0
H0
R/W
10 BRDIV
0
H0
R/W
9
INVRX
0
H0
R/W
8
INVTX
0
H0
R/W
7
–
0
–
R
6
PUEN
0
H0
R/W
5
OUTMD
0
H0
R/W
4
IRMD
0
H0
R/W
3
CHLN
0
H0
R/W
2
PREN
0
H0
R/W
1
PRMD
0
H0
R/W
0
STPB
0
H0
R/W
Bits 15–13 Reserved