Unexpected Transmit Frame-Synchronization Pulse; Underflow Prevented In The Mcbsp Transmitter; Possible Responses To Transmit Frame-Synchronization Pulses - Texas Instruments Concerto F28M35 Series Technical Reference Manual

McBSP Exception/Error Conditions
Figure 15-28. Underflow Prevented in the McBSP Transmitter
CLKX
FSX
A1
DX
XRDY
XEMPTY_

15.5.5 Unexpected Transmit Frame-Synchronization Pulse

Section 15.5.5.1 shows how the McBSP responds to any transmit frame-synchronization pulses, including
an unexpected pulse.
error and an example of how to prevent such an error, respectively.

15.5.5.1 Possible Responses to Transmit Frame-Synchronization Pulses

Figure 15-29 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-
1062
C28 Multichannel Buffered Serial Port (McBSP)
A0 B7 B6 B5
DXR1 to XSR1 copy
Section 15.5.5.2 and Section 15.5.5.3
Transmit frame-sync
pulse occurs.
Unexpected
frame-sync
pulse
?
Yes
XFIG=1
?
Yes
Case 1:
With frame ignore
ignore frame pulse.
Transmit stays
running.
Copyright © 2012–2019, Texas Instruments Incorporated
B4 B3 B2 B1 B0
Write to DXR1(C)
show examples of a frame-synchronization
Case 2:
No
Normal transmission.
Start new transmit.
Case 3:
Without frame ignore
No
abort transfer.
Set XSYNCERR.
Restart current
transfer.
SPRUH22I – April 2012 – Revised November 2019
www.ti.com
C7 C6 C5
DXR1 to XSR1 copy(C)
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