Receiver Configuration
www.ti.com
704
SPRUI07–March 2020
Submit Documentation Feedback
Copyright © 2020, Texas Instruments Incorporated
Multichannel Buffered Serial Port (McBSP)
Table 12-27. Register Bits Used to Set the Receive Frame Length (continued)
Regist
er Bit Name Function Type
Reset
Value
RCR2 14-8 RFRLEN2 Receive frame length 2 R/W 000 0000
If a dual-phase frame is selected, (RFRLEN2 + 1) is the number of serial
words in phase 2 of the receive frame.
RFRLEN2 = 000 0000 1 word in phase 2
RFRLEN2 = 000 0001 2 words in phase 2
| |
| |
RFRLEN2 = 111 1111 128 words in phase 2
12.8.9.1 Selected Frame Length
The receive frame length is the number of serial words in the receive frame. Each frame can have one or
two phases, depending on value that you load into the RPHASE bit.
If a single-phase frame is selected (RPHASE = 0), the frame length is equal to the length of phase 1. If a
dual-phase frame is selected (RPHASE = 1), the frame length is the length of phase 1 plus the length of
phase 2.
The 7-bit RFRLEN fields allow up to 128 words per phase. See Table 12-28 for a summary of how to
calculate the frame length. This length corresponds to the number of words or logical time slots or
channels per frame-synchronization pulse.
Program the RFRLEN fields with [w minus 1], where w represents the number of words per phase. For the
example, if you want a phase length of 128 words in phase 1, load 127 into RFRLEN1.
Table 12-28. How to Calculate the Length of the Receive Frame
RPHASE RFRLEN1 RFRLEN2 Frame Length
0 0 ≤ RFRLEN1 ≤ 127 Don't care (RFRLEN1 + 1) words
1 0 ≤ RFRLEN1 ≤ 127 0 ≤ RFRLEN2 ≤ 127 (RFRLEN1 + 1) + (RFRLEN2 + 1) words
12.8.10 Receive Frame-Synchronization Ignore Function
The RFIG bit (see Table 12-29) controls the receive frame-synchronization ignore function.
Table 12-29. Register Bit Used to Enable/Disable the Receive Frame-Synchronization Ignore
Function
Registe
r Bit Name Function Type
Reset
Value
RCR2 2 RFIG Receive frame-synchronization ignore R/W 0
RFIG = 0 An unexpected receive frame-synchronization pulse causes the
McBSP to restart the frame transfer.
RFIG = 1 The McBSP ignores unexpected receive frame-synchronization
pulses.
12.8.10.1 Unexpected Frame-Synchronization Pulses and the Frame-Synchronization Ignore Function
If a frame-synchronization pulse starts the transfer of a new frame before the current frame is fully
received, this pulse is treated as an unexpected frame-synchronization pulse.
When RFIG = 1, reception continues, ignoring the unexpected frame-synchronization pulses.
To Next Page
Need help?
General
