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eUSCI_A Operation – UART Mode
Table 18-5. Recommended Settings for Typical Crystals and Baudrates (continued)
TX error (%)
RX error (%)
BRCLK
Baudrate
UCOS16
UCBRx
UCBRFx
UCBRSx
neg
pos
neg
pos
12000000
19200
1
39
1
0x0
0
0
0
0.16
12000000
38400
1
19
8
0x65
-0.16
0.16
-0.4
0.24
12000000
57600
1
13
0
0x25
-0.16
0.32
-0.48
0.48
12000000
115200
1
6
8
0x20
-0.48
0.64
-1.04
1.04
12000000
230400
1
3
4
0x2
-0.8
0.96
-1.84
1.84
12000000
460800
1
1
10
0x0
0
1.76
0
3.44
16000000
9600
1
104
2
0xD6
-0.04
0.02
-0.09
0.03
16000000
19200
1
52
1
0x49
-0.08
0.04
-0.1
0.14
16000000
38400
1
26
0
0xB6
-0.08
0.16
-0.28
0.2
16000000
57600
1
17
5
0xDD
-0.16
0.2
-0.3
0.38
16000000
115200
1
8
10
0xF7
-0.32
0.32
-1
0.36
16000000
230400
1
4
5
0x55
-0.8
0.64
-1.12
1.76
16000000
460800
1
2
2
0xBB
-1.44
1.28
-3.92
1.68
16777216
9600
1
109
3
0xB5
-0.03
0.02
-0.05
0.06
16777216
19200
1
54
9
0xEE
-0.06
0.06
-0.11
0.13
16777216
38400
1
27
4
0xFB
-0.11
0.1
-0.33
0
16777216
57600
1
18
3
0x44
-0.16
0.15
-0.2
0.45
16777216
115200
1
9
1
0xB5
-0.31
0.31
-0.53
0.78
16777216
230400
1
4
8
0xEE
-0.75
0.74
-2
0.87
16777216
460800
1
2
4
0x92
-1.62
1.37
-3.56
2.06
20000000
9600
1
130
3
0x25
-0.02
0.03
0
0.07
20000000
19200
1
65
1
0xD6
-0.06
0.03
-0.1
0.1
20000000
38400
1
32
8
0xEE
-0.1
0.13
-0.27
0.14
20000000
57600
1
21
11
0x22
-0.16
0.13
-0.16
0.38
20000000
115200
1
10
13
0xAD
-0.29
0.26
-0.46
0.66
20000000
230400
1
5
6
0xEE
-0.67
0.51
-1.71
0.62
20000000
460800
1
2
11
0x92
-1.38
0.99
-1.84
2.8
18.3.14 Using the eUSCI_A Module in UART Mode With Low-Power Modes
The eUSCI_A module provides automatic clock activation for use with low-power modes. When the
eUSCI_A clock source is inactive because the device is in a low-power mode, the eUSCI_A module
automatically activates it when needed, regardless of the control-bit settings for the clock source. The
clock remains active until the eUSCI_A module returns to its idle condition. After the eUSCI_A module
returns to the idle condition, control of the clock source reverts to the settings of its control bits.
18.3.15 eUSCI_A Interrupts
The eUSCI_A has only one interrupt vector that is shared for transmission and for reception.
18.3.15.1 eUSCI_A Transmit Interrupt Operation
The UCTXIFG interrupt flag is set by the transmitter to indicate that UCAxTXBUF is ready to accept
another character. An interrupt request is generated if UCTXIE and GIE are also set. UCTXIFG is
automatically reset if a character is written to UCAxTXBUF.
UCTXIFG is set after a PUC or when UCSWRST = 1. UCTXIE is reset after a PUC or when
UCSWRST = 1.
492
Enhanced Universal Serial Communication Interface (eUSCI) – UART Mode
SLAU272C – May 2011 – Revised November 2013
Copyright © 2011–2013, Texas Instruments Incorporated