McBSP Registers
1163
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Multichannel Buffered Serial Port (McBSP)
Table 15-73. Serial Port Control 2 Register (SPCR2) Field Descriptions (continued)
Bit
Field
Value
Description
0
XRST
Transmitter reset bit. You can use XRST to take the McBSP transmitter into and out of its reset state.
This bit has a negative polarity; XRST = 0 indicates the reset state.
To read about the effects of a transmitter reset, see
,
Resetting and Initializing a
McBSP
.
0
If you read a 0, the transmitter is in its reset state.
If you write a 0, you reset the transmitter.
1
If you read a 1, the transmitter is enabled.
If you write a 1, you enable the transmitter by taking it out of its reset state.
15.12.5 Receive Control Registers (RCR[1, 2])
Each McBSP has two receive control registers, RCR1 (
). These
registers enable you to:
•
Specify one or two phases for each frame of receive data (RPHASE)
•
Define two parameters for phase 1 and (if necessary) phase 2: the serial word length (RWDLEN1,
RWDLEN2) and the number of words (RFRLEN1, RFRLEN2)
•
Choose a receive companding mode, if any (RCOMPAND)
•
Enable or disable the receive frame-synchronization ignore function (RFIG)
•
Choose a receive data delay (RDATDLY)
15.12.5.1 Receive Control Register 1 (RCR1)
The receive control register 1 (RCR1) is shown in
and described in
Figure 15-69. Receive Control Register 1 (RCR1)
15
14
8
Reserved
RFRLEN1
R-0
R/W-0
7
5
4
0
RWDLEN1
Reserved
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 15-74. Receive Control Register 1 (RCR1) Field Descriptions
Bit
Field
Value
Description
15
Reserved
0
Reserved bits (not available for your use). They are read-only bits and return 0s when read.
14-8
RFRLEN1
0-7Fh
Receive frame length 1 (1 to 128 words). Each frame of receive data can have one or two phases,
depending on value that you load into the RPHASE bit. If a single-phase frame is selected, RFRLEN1 in
RCR1 selects the number of serial words (8, 12, 16, 20, 24, or 32 bits per word) in the frame. If a dual-
phase frame is selected, RFRLEN1 determines the number of serial words in phase 1 of the frame, and
RFRLEN2 in RCR2 determines the number of words in phase 2 of the frame. The 7-bit RFRLEN fields
allow up to 128 words per phase. See
for a summary of how you determine the frame
length. This length corresponds to the number of words or logical time slots or channels per frame-
synchronization period.
Program the RFRLEN fields with [
w minus 1
], where
w
represents the number of words per phase. For
example, if you want a phase length of 128 words in phase 1, load 127 into RFRLEN1.