DX
FSX
CLKX
DR
FSR
CLKR
DXR to XSR copy
DXR to XSR copy
DXR to XSR copy
DXR to XSR copy
RB to DRR copy
RB to DRR copy
RB to DRR copy
RB to DRR copy
Word 4
Word 3
Word 2
Word 1
mcbsp-060
Word 1
DXR to XSR copy
CLKX
Frame ignored
Frame ignored
FSX
DX
Frame ignored
DXR to XSR copy
DR
FSR
CLKR
RB to DRR copy
RB to DRR copy
Frame ignored
Frame ignored
Frame ignored
mcbsp-061
Public Version
McBSP Basic Programming Model
www.ti.com
Figure 21-72. 8-bit Data Words Transferred at Maximum Packet Frequency
shows the McBSP configured to treat this data stream as a continuous 32-bit word. In this
example, the McBSP responds to an initial frame-sync pulse. However, the McBSP ignores subsequent
pulses. Only one read transfer or one write transfer is required every 32 bits. This configuration effectively
reduces the required bus bandwidth to one-fourth the bandwidth needed to transfer four 8-bit words.
Figure 21-73. Configuring the Data Stream as a Continuous 32-bit Word
21.5.2 SIDETONE Feature
21.5.2.1 SIDETONE Activation Procedure
Before you enable a SIDETONE selection mode, make sure you properly configure the data frame for
multichannel mode of the McBSP module:
•
Select a single–phase frame (McBSPi.
[15] RPHASE bit and
[15] XPHASE bit=0). Each frame represents a TDM data stream.
•
Set to 1 the McBSPi.
[0] RMCM bit, to select multichannel mode enable.
•
Set a frame length (McBSPi.
[14:8] RFRLEN1 bit field and
[14:8] XFRLEN1 bit field) that includes the highest–numbered channel
to be used (a maximum of 4 channels can be used in this configuration).
•
Set a word length (McBSPi.
[7:5] RWDLEN1 bit field and
[7:5] XWDLEN1 bit field) to be either 16, 24 or 32 (see the note
3152
Multi-Channel Buffered Serial Port
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated