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Registers
1248
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multichannel Buffered Serial Port (McBSP)
25.3.5 Transmit Control Register (XCR)
The transmit control register (XCR) configures parameters of the transmit operations. The XCR is shown
in
and described in
.
Figure 25-46. Transmit Control Register (XCR)
31
30
24
23
21
20
19
18
17
16
XPHASE
XFRLEN2
XWDLEN2
XCOMPAND
XFIG
XDATDLY
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
15
14
8
7
5
4
3
0
Reserved
XFRLEN1
XWDLEN1
XWDREVRS
Reserved
R-0
R/W-0
R/W-0
R/W-0
R-0
LEGEND: R = Read only; R/ W = Read/Write; -n = value after reset
Table 25-27. Transmit Control Register (XCR) Field Descriptions
Bit
Field
Value
Description
31
XPHASE
Transmit phases bit.
0
Single-phase frame
1
Dual-phase frame
30-24
XFRLEN2
0-7Fh
Specifies the transmit frame length (number of words) in phase 2.
0
1 word in phase 2
1h
2 words in phase 2
2h
3 words in phase 2
...
...
7Fh
128 words in phase 2
23-21
XWDLEN2
0-7h
Specifies the transmit word length (number of bits) in phase 2.
0
Transmit word length is 8 bits.
1h
Transmit word length is 12 bits.
2h
Transmit word length is 16 bits.
3h
Transmit word length is 20 bits.
4h
Transmit word length is 24 bits.
5h
Transmit word length is 32 bits.
6h-7h
Reserved
20-19
XCOMPAND
0-3h
Transmit companding mode bit. Modes other than 00 are only enabled when XWDLEN1/2 bit is 000
(indicating 8-bit data).
0
No companding, data transfer starts with MSB first.
1h
No companding, 8-bit data transfer starts with LSB first.
2h
Compand using
μ
-law for transmit data.
3h
Compand using A-law for transmit data.
18
XFIG
Transmit frame ignore bit.
0
Transmit frame-synchronization pulses after the first pulse restarts the transfer.
1
Transmit frame-synchronization pulses after the first pulse are ignored.
17-16
XDATDLY
0-3h
Transmit data delay bit.
0
0-bit data delay
1h
1-bit data delay
2h
2-bit data delay
3h
Reserved
15
Reserved
0
Reserved. The reserved bit location is always read as 0. A value written to this field has no effect.