eUSCI_A Operation – UART Mode
782
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Enhanced Universal Serial Communication Interface (eUSCI) – UART Mode
The receive error is the accumulated time versus the ideal scanning time in the middle of each bit. The
worst-case error is given for the reception of an 8-bit character with parity and one stop bit including
synchronization error.
The transmit error is the accumulated timing error versus the ideal time of the bit period. The worst-case
error is given for the transmission of an 8-bit character with parity and stop bit.
(1)
The listed UCBRSx settings are determined by a search algorithm for the lowest error. Other settings for UCBRSx might result in
similar or same errors.
(2)
Assumes a stable clock source for BRCLK with negligible jitter (for example, from a crystal oscillator). Any frequency variation or
jitter of the clock source will make the errors worse.
Table 30-5. Recommended Settings for Typical Crystals and Baud Rates
(1)
BRCLK
Baud Rate
UCOS16
UCBRx
UCBRFx
UCBRSx
(2)
TX Error
(2)
(%)
RX Error
(2)
(%)
neg
pos
neg
pos
32768
1200
1
1
11
0x25
-2.29
2.25
-2.56
5.35
32768
2400
0
13
-
0xB6
-3.12
3.91
-5.52
8.84
32768
4800
0
6
-
0xEE
-7.62
8.98
-21
10.25
32768
9600
0
3
-
0x92
-17.19
16.02
-23.24
37.3
1000000
9600
1
6
8
0x20
-0.48
0.64
-1.04
1.04
1000000
19200
1
3
4
0x2
-0.8
0.96
-1.84
1.84
1000000
38400
1
1
10
0x0
0
1.76
0
3.44
1000000
57600
0
17
-
0x4A
-2.72
2.56
-3.76
7.28
1000000
115200
0
8
-
0xD6
-7.36
5.6
-17.04
6.96
1048576
9600
1
6
13
0x22
-0.46
0.42
-0.48
1.23
1048576
19200
1
3
6
0xAD
-0.88
0.83
-2.36
1.18
1048576
38400
1
1
11
0x25
-2.29
2.25
-2.56
5.35
1048576
57600
0
18
-
0x11
-2
3.37
-5.31
5.55
1048576
115200
0
9
-
0x08
-5.37
4.49
-5.93
14.92
4000000
9600
1
26
0
0xB6
-0.08
0.16
-0.28
0.2
4000000
19200
1
13
0
0x84
-0.32
0.32
-0.64
0.48
4000000
38400
1
6
8
0x20
-0.48
0.64
-1.04
1.04
4000000
57600
1
4
5
0x55
-0.8
0.64
-1.12
1.76
4000000
115200
1
2
2
0xBB
-1.44
1.28
-3.92
1.68
4000000
230400
0
17
-
0x4A
-2.72
2.56
-3.76
7.28
4194304
9600
1
27
4
0xFB
-0.11
0.1
-0.33
0
4194304
19200
1
13
10
0x55
-0.21
0.21
-0.55
0.33
4194304
38400
1
6
13
0x22
-0.46
0.42
-0.48
1.23
4194304
57600
1
4
8
0xEE
-0.75
0.74
-2
0.87
4194304
115200
1
2
4
0x92
-1.62
1.37
-3.56
2.06
4194304
230400
0
18
-
0x11
-2
3.37
-5.31
5.55
8000000
9600
1
52
1
0x49
-0.08
0.04
-0.1
0.14
8000000
19200
1
26
0
0xB6
-0.08
0.16
-0.28
0.2
8000000
38400
1
13
0
0x84
-0.32
0.32
-0.64
0.48
8000000
57600
1
8
10
0xF7
-0.32
0.32
-1
0.36
8000000
115200
1
4
5
0x55
-0.8
0.64
-1.12
1.76
8000000
230400
1
2
2
0xBB
-1.44
1.28
-3.92
1.68
8000000
460800
0
17
-
0x4A
-2.72
2.56
-3.76
7.28
8388608
9600
1
54
9
0xEE
-0.06
0.06
-0.11
0.13
8388608
19200
1
27
4
0xFB
-0.11
0.1
-0.33
0
8388608
38400
1
13
10
0x55
-0.21
0.21
-0.55
0.33
8388608
57600
1
9
1
0xB5
-0.31
0.31
-0.53
0.78
8388608
115200
1
4
8
0xEE
-0.75
0.74
-2
0.87