Isosynchronous baud value
=
)
(
VCLK Frequency
2
Asynchronous baud value
=
)
(
VCLK Frequency
32
Isosynchronous baud value
=
)
(
VCLK Frequency
Baud + 1
Asynchronous baud value
=
)
(
VCLK Frequency
16(Baud + 1)
SCI Control Registers
1751
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Serial Communication Interface (SCI) Module
30.7.11 Baud Rate Selection Register (BRS)
This section describes the baud rate selection register.
and
illustrate this
register.
Figure 30-18. Baud Rate Selection Register (BRS) [offset = 2Ch]
31
24
23
16
Reserved
BAUD
R-0
R/W-0
15
0
BAUD
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 30-16. Baud Rate Selection Register (BRS) Field Descriptions
Bit
Field
Value
Description
31-24
Reserved
0
Reads return 0. Writes have no effect.
23-0
BAUD
0-FF FFFFh
SCI 24-bit baud selection.
The SCI has an internally generated serial clock determined by the VCLK and the prescalers
BAUD in this register. The SCI uses the 24-bit integer prescaler BAUD value of this register to
select one of over 16,700,000.
The baud rate can be calculated using the following formulas:
(59)
(60)
For BAUD = 0,
(61)
(62)
contains comparative baud values for different P values, with VCLK = 50 MHz, for
asynchronous mode..
(1)
VCLK = 50 MHz
(2)
Values are in decimal except for column 2.
Table 30-17. Comparative Baud Values for Different P Values, Asynchronous Mode
(1) (2)
24-Bit Register Value
Baud Selected
Percent Error
Decimal
Hex
Ideal
Actual
26
00001A
115200
115740
0.47
53
000035
57600
57870
0.47
80
000050
38400
38580
0.47
162
0000A2
19200
19172
-0.15
299
00012B
10400
10417
0.16
325
000145
9600
9586
-0.15
399
00018F
7812.5
7812.5
0.00
650
00028A
4800
4800
0.00
15624
003BA0
200
200
0.00
624999
098967
5
5
0.00