
Registers
1244
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multichannel Buffered Serial Port (McBSP)
25.3.3 Serial Port Control Register (SPCR)
The serial port is configured via the serial port control register (SPCR) and the pin control register (PCR).
The SPCR contains McBSP status control bits. The SPCR is shown in
and described in
.
Figure 25-44. Serial Port Control Register (SPCR)
31
26
25
24
Reserved
FREE
SOFT
R-0
R/W-0
R/W-0
23
22
21
20
19
18
17
16
FRST
GRST
XINTM
XSYNCERR
XEMPTY
XRDY
XRST
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R-0
R/W-0
15
14
13
12
11
10
8
DLB
RJUST
CLKSTP
Reserved
R/W-0
R/W-0
R-0
R-0
7
6
5
4
3
2
1
0
DXENA
Reserved
RINTM
RSYNCERR
RFULL
RRDY
RRST
R/W-0
R-0
R/W-0
R/W-0
R-0
R-0
R/W-0
LEGEND: R = Read only; R/W = Read/ Write; -n = value after reset
Table 25-25. Serial Port Control Register (SPCR) Field Descriptions
Bit
Field
Value
Description
31-26
Reserved
0
Reserved. The reserved bit location is always read as 0. A value written to this field has no effect.
25
FREE
Free-running enable mode bit. This bit is used in conjunction with SOFT bit to determine state of serial
port clock during emulation halt.
0
Free-running mode is disabled. During emulation halt, SOFT bit determines operation of McBSP.
1
Free-running mode is enabled. During emulation halt, serial clocks continue to run.
24
SOFT
Soft bit enable mode bit. This bit is used in conjunction with FREE bit to determine state of serial port
clock during emulation halt. This bit has no effect if FREE = 1.
0
Soft mode is disabled. Serial port clock stops immediately during emulation halt, thus aborting any
transmissions.
1
Soft mode is enabled. During emulation halt, serial port clock stops after completion of current
transmission.
23
FRST
Frame-sync generator reset bit.
0
Frame-synchronization logic is reset. Frame-sync signal (FSG) is not generated by the sample-rate
generator.
1
Frame-sync signal (FSG) is generated after (FPER + 1) number of CLKG clocks; that is, all frame
counters are loaded with their programmed values.
22
GRST
Sample-rate generator reset bit.
0
Sample-rate generator is reset.
1
Sample-rate generator is taken out of reset. CLKG is driven as per programmed value in sample-rate
generator register (SRGR).
21-20
XINTM
0-3h
Transmit interrupt (XINT) mode bit.
0
XINT is driven by XRDY (end-of-word).
1h
Reserved
2h
XINT is generated by a new frame synchronization.
3h
XINT is generated by XSYNCERR.
19
XSYNCERR
Transmit synchronization error bit. Writing a 1 to XSYNCERR sets the error condition when the
transmitter is enabled (XRST = 1). Thus, it is used mainly for testing purposes or if this operation is
desired.
0
No synchronization error is detected.
1
Synchronization error is detected.