McBSP Registers
1127
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Multichannel Buffered Serial Port (McBSP)
Table 15-74. Receive Control Register 1 (RCR1) Field Descriptions (continued)
Bit
Field
Value
Description
7-5
RWDLEN1
0-7h
Receive word length 1. Each frame of receive data can have one or two phases, depending on the
value that you load into the RPHASE bit. If a single-phase frame is selected, RWDLEN1 in RCR1
selects the length for every serial word received in the frame. If a dual-phase frame is selected,
RWDLEN1 determines the length of the serial words in phase 1 of the frame, and RWDLEN2 in RCR2
determines the word length in phase 2 of the frame.
0
8 bits
1h
12 bits
2h
16 bits
3h
20 bits
4h
24 bits
5h
32 bits
6h-7h
Reserved (do not use)
4-0
Reserved
0
Reserved bits (not available for your use). They are read-only bits and return 0s when read.
Table 15-75. Frame Length Formula for Receive Control 1 Register (RCR1)
RPHASE
RFRLEN1
RFRLEN2
Frame Length
0
0
≤
RFRLEN1
≤
127
Not used
(R 1) words
1
0
≤
RFRLEN1
≤
127
0
≤
RFRLEN2
≤
127
(R 1) + (R 1) words
15.12.5.2 Receive Control Register 2 (RCR2)
The receive control register 2 (RCR2) is shown in
and described in
Figure 15-70. Receive Control Register 2 (RCR2)
15
14
8
RPHASE
RFRLEN2
R/W-0
R/W-0
7
5
4
3
2
1
0
RWDLEN2
RCOMPAND
RFIG
RDATDLY
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 15-76. Receive Control Register 2 (RCR2) Field Descriptions
Bit
Field
Value
Description
15
RPHASE
Receive phase number bit. RPHASE determines whether the receive frame has one phase or two
phases. For each phase you can define the serial word length and the number of serial words in the
phase. To set up phase 1, program RWDLEN1 (word length) and RFRLEN1 (number of words). To set
up phase 2 (if there are two phases), program RWDLEN2 and RFRLEN2.
0
Single-phase frame
The receive frame has only one phase, phase 1.
1
Dual-phase frame
The receive frame has two phases, phase 1 and phase 2.
14-8
0-7Fh
Receive frame length 2 (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 to 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 2, load 127 into RFRLEN2.