SN8P26L38
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 124
Version 1.5
12.5
UART BAUD RATE CONTROL REGISTER
URBRC initial value = 11010101
0A6H
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
URBRC
UDIV4
UDIV3
UDIV2
UDIV1
UDIV0
UPCS2
UPCS1
UPCS0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
After reset
1
1
0
1
0
1
0
1
Bit[7:3]
UDIV[4:0]:
UART baud rate divider.
Bit[2:0]
UPCS[2:0]:
UART baud rate pre-scalar.
000=Fhosc/2, 001=Fhosc/4, 010=Fhosc/8, 011=Fhosc/16, 100=Fhosc/32, 101=Fhosc/64, 110=Fhosc/128,
111=Fhosc/256
The UART baud rate clock source is Fhosc and divided by pre-scalar and divider. The equation is as following.
Pre-scaler UPCS[2:0]=000b, 001b:
UART Baud Rate = Fhosc/2
PreScaler
/(1)/16
Pre-scaler UPCS[2:0]=010b~111b:
UART Baud Rate = Fhosc/2
PreScaler
/(Divider)/16
Baud Rate
Fhosc = 16MHz
Fhosc = 8MHz
Fhosc = 4MHz
UPCS[2:0] UDIV[4:0] Inaccuracy UPCS[2:0] UDIV[4:0] Inaccuracy UPCS[2:0] UDIV[4:0] Inaccuracy
1200
101
11010
0.16%
100
11010
0.16%
011
11010
0.16%
2400
100
11010
0.16%
011
11010
0.16%
010
11010
0.16%
4800
011
11010
0.16%
010
11010
0.16%
001
11001
0.16%
9600
010
11010
0.16%
010
01101
0.16%
000
11001
0.16%
14400
010
10001
2.12%
001
10000
2.12%
000
10000
2.12%
19200
010
01101
0.16%
000
11001
0.16%
000
01100
0.16%
38400
001
01100
0.16%
000
01100
0.16%
000
00110
-6.99%
51200
000
10010
2.80%
000
01001
-2.34%
000
00100
-2.34%
57600
000
10000
2.12%
000
01000
-3.55%
000
00011
8.51%
102400
000
01001
-2.34%
000
00100
-2.34%
000
00010
-18.62%
115200
000
01000
-3.55%
000
00011
8.51%
000
00001
8.51%