Yes
No
Yes
No
running.
Receiver continues
ignore frame pulse.
With frame ignore,
Case 1:
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
Previous word is lost.
immediately.
Start next reception
Set RSYNCERR.
abort reception.
Without frame ignore,
Case 3:
Start receiving data.
Normal reception.
Case 2:
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
pulse occurs.
Receive frame-sync
?
RFIG=1
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
?
pulse
frame-sync
Unexpected
RBR1 to DRR1(B)
No RBR1 to DRR1 copy(B)
No read From DRR1(A)
RBR1 to DRR1 copy(A)
C0
C1
C2
C3
C4
C5
C6
C7
B0
B1
B2
B3
B4
B5
B6
B7
A0
A1
RFULL
RRDY
DR
FSR
CLKR
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Á
Read from DRR1(A)
McBSP Exception/Error Conditions
1058
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Multichannel Buffered Serial Port (McBSP)
Figure 15-22. Overrun Prevented in the McBSP Receiver
15.5.3 Unexpected Receive Frame-Synchronization Pulse
shows how the McBSP responds to any receive frame-synchronization pulses, including
an unexpected pulse.
and
show an examples of a frame-synchronization
error and an example of how to prevent such an error, respectively.
15.5.3.1 Possible Responses to Receive Frame-Synchronization Pulses
shows the decision tree that the receiver uses to handle all incoming frame-synchronization
pulses. The figure assumes that the receiver has been started (RRST = 1 in SPCR1). Case 3 in the figure
is the case in which an error occurs.
Figure 15-23. Possible Responses to Receive Frame-Synchronization Pulses
Any one of three cases can occur:
•
Case 1: Unexpected internal FSR pulses with RFIG = 1 in RCR2. Receive frame-synchronization
pulses are ignored, and the reception continues.
•
Case 2: Normal serial port reception. Reception continues normally because the frame-synchronization