SCI Asynchronous Baud
LSPCLK
16
=
BRR
LSPCLK
SCI Asynchronous Baud
8
1
=
×
−
SCI Asynchronous Baud
LSPCLK
(BRR
1)
8
=
×
+
SCI Registers
998
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Serial Communications Interface (SCI)
13.3.4 SCI Baud-Select Registers (SCIHBAUD, SCILBAUD)
The values in SCIHBAUD and SCILBAUD specify the baud rate for the SCI.
Figure 13-14. Baud-Select MSbyte Register (SCIHBAUD) — Address 7052h
15
14
13
12
11
10
9
8
BAUD15 (MSB)
BAUD14
BAUD13
BAUD12
BAUD11
BAUD10
BAUD9
BAUD8
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Figure 13-15. Baud-Select LSbyte Register (SCILBAUD) — Address 7053h
7
6
5
4
3
2
1
0
BAUD7
BAUD6
BAUD5
BAUD4
BAUD3
BAUD2
BAUD1
BAUD10 (LSB)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 13-11. Baud-Select Register Field Descriptions
Bit
Field
Value
Description
15-0
BAUD15
−
BAUD0
SCI 16-bit baud selection Registers SCIHBAUD (MSbyte) and SCILBAUD (LSbyte) are
concatenated to form a 16-bit baud value, BRR.
The internally-generated serial clock is determined by the low speed peripheral clock (LSPCLK)
signal and the two baud-select registers. The SCI uses the 16-bit value of these registers to select
one of 64K serial clock rates for the communication modes.
The SCI baud rate is calculated using the following equation:
(8)
Alternatively,
(9)
Note that the above formulas are applicable only when 1
≤
BRR
≤
65535. If BRR = 0, then
(10)
Where: BRR = the 16-bit value (in decimal) in the baud-select registers.