Yes
No
Yes
No
running.
Transmit stays
ignore frame pulse.
With frame ignore
Case 1:
transfer.
Restart current
Set XSYNCERR.
abort transfer.
Without frame ignore
Case 3:
Start new transmit.
Normal transmission.
Case 2:
pulse occurs.
Transmit frame-sync
?
XFIG=1
?
pulse
frame-sync
Unexpected
XEMPTY_
Á
Á
Á
Á
Á
Á
C5
C6
C7
B0
B1
B2
B3
B4
B5
B6
B7
A0
A1
XRDY
DX
FSX
CLKX
Á
Á
Á
Á
Á
Á
DXR1 to XSR1 copy(C)
Write to DXR1(C)
DXR1 to XSR1 copy
McBSP Exception/Error Conditions
1099
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Multichannel Buffered Serial Port (McBSP)
Figure 15-28. Underflow Prevented in the McBSP Transmitter
15.5.5 Unexpected Transmit Frame-Synchronization Pulse
shows how the McBSP responds to any transmit frame-synchronization pulses, including
an unexpected pulse.
and
show examples of a frame-synchronization
error and an example of how to prevent such an error, respectively.
15.5.5.1 Possible Responses to Transmit Frame-Synchronization Pulses
shows the decision tree that the transmitter uses to handle all incoming frame-
synchronization pulses. The figure assumes that the transmitter has been started (XRST = 1 in SPCR2).
Case 3 in the figure is the case in which an error occurs.
Figure 15-29. Possible Responses to Transmit Frame-Synchronization Pulses
Any one of three cases can occur:
•
Case 1: Unexpected internal FSX pulses with XFIG = 1 in XCR2. Transmit frame-synchronization
pulses are ignored, and the transmission continues.
•
Case 2: Normal serial port transmission. Transmission continues normally because the frame-