Enable/Disable The Transmit Frame-Synchronization Ignore Function; Unexpected Frame-Synchronization Pulse With (R/X) Fig; Register Bit Used To Enable/Disable The Transmit Frame-Synchronization Ignore Function - Texas Instruments Concerto F28M36 Series Technical Reference Manual

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15.9.10 Enable/Disable the Transmit Frame-Synchronization Ignore Function

Table 15-57. Register Bit Used to Enable/Disable the Transmit Frame-Synchronization Ignore
Register Bit
XCR2 2
15.9.10.1 Unexpected Frame-Synchronization Pulses and Frame-Synchronization Ignore
If a frame-synchronization pulse starts the transfer of a new frame before the current frame is fully
transmitted, this pulse is treated as an unexpected frame-synchronization pulse.
When XFIG = 1, normal transmission continues with unexpected frame-synchronization signals ignored.
When XFIG = 0 and an unexpected frame-synchronization pulse occurs, the serial port:
1. Aborts the present transmission
2. Sets XSYNCERR to 1 in SPCR2
3. Reinitiates transmission of the current word that was aborted
For more details about the frame-synchronization error condition, see
Transmit Frame-Synchronization Pulse.
15.9.10.2 Examples Showing the Effects of XFIG
Figure 15-51 shows an example in which word B is interrupted by an unexpected frame-synchronization
pulse when (R/X)FIG = 0. In the case of transmission, the transmission of B is aborted (B is lost). This
condition is a transmit synchronization error, which sets the XSYNCERR bit. No new data has been
written to DXR[1,2]; therefore, the McBSP transmits B again.
Figure 15-51. Unexpected Frame-Synchronization Pulse With (R/X) FIG = 0
CLK(R/X)
FS(R/X)
DR
DX
(R/X)SYNCERR
In contrast with Figure
synchronization signals are ignored (when (R/X)FIG = 1). Here, the transfer of word B is not affected by
an unexpected frame-synchronization pulse.
SPRUHE8E – October 2012 – Revised November 2019
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Name Function
XFIG Transmit frame-synchronization ignore
XFIG = 0
XFIG = 1
Frame synchronization aborts current transfer
A0 B7 B6 C7 C6
A0 B7 B6 B7 B6
15-51, Figure 15-52 shows McBSP operation when unexpected frame-
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Function
An unexpected transmit frame-synchronization
pulse causes the McBSP to restart the frame
transfer.
The McBSP ignores unexpected transmit frame-
synchronization pulses.
Section
New data received
C5 C4 C3 C2
Current data retransmitted
B5 B4 B3 B2
C28 Multichannel Buffered Serial Port (McBSP)
Transmitter Configuration
Type
R/W
15.5.5, Unexpected
C1 C0 D7 D6
B1 B0 C7 C6
Reset
Value
0
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