McBSP Registers
1174
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Multichannel Buffered Serial Port (McBSP)
Table 15-85. Multichannel Control 2 Register (MCR2) Field Descriptions (continued)
Bit
Field
Value
Description
8-7
XPBBLK
0-3h
Transmit partition B block bits
XPBBLK is only applicable if channels can be individually disabled/enabled and masked/unmasked
(XMCM is nonzero) and the 2-partition mode is selected (XMCME = 0). Under these conditions, the
McBSP transmitter can transmit or withhold data in any of the 32 channels that are assigned to
partitions A and B of the transmitter.
The 128 transmit channels of the McBSP are divided equally among 8 blocks (0 through 7). When
XPBBLK is applicable, use XPBBLK to assign one of the odd-numbered blocks (1, 3, 5, or 7) to
partition B, as shown in the following table. Use the XPABLK bit to assign one of the even-
numbered blocks (0, 2, 4, or 6) to partition A.
If you want to use more than 32 channels, you can change block assignments dynamically. You
can assign a new block to one partition while the transmitter is handling activity in the other
partition. For example, while the block in partition A is active, you can change which block is
assigned to partition B. The XCBLK bits are regularly updated to indicate which block is active.
When XMCM = 11b (for symmetric transmission and reception), the transmitter uses the receive
block bits (RPABLK and RPBBLK) rather than the transmit block bits (XPABLK and XPBBLK).
0
Block 1: channels 16 through 31
1h
Block 3: channels 48 through 63
2h
Block 5: channels 80 through 95
3h
Block 7: channels 112 through 127
6-5
XPABLK
Transmit partition A block bits. XPABLK is only applicable if channels can be individually
disabled/enabled and masked/unmasked (XMCM is nonzero) and the 2-partition mode is selected
(XMCME = 0). Under these conditions, the McBSP transmitter can transmit or withhold data in any
of the 32 channels that are assigned to partitions A and B of the transmitter. See the description for
XPBBLK (bits 8-7) for more information about assigning blocks to partitions A and B.
0
Block 0: channels 0 through 15
1h
Block 2: channels 32 through 47
2h
Block 4: channels 64 through 79
3h
Block 6: channels 96 through 111
4-2
XCBLK
Transmit current block indicator. XCBLK indicates which block of 16 channels is involved in the
current McBSP transmission:
0
Block 0: channels 0 through 15
1h
Block 1: channels 16 through 31
2h
Block 2: channels 32 through 47
3h
Block 3: channels 48 through 63
4h
Block 4: channels 64 through 79
5h
Block 5: channels 80 through 95
6h
Block 6: channels 96 through 111
7h
Block 7: channels 112 through 127
1-0
XMCM
0-3h
Transmit multichannel selection mode bits. XMCM determines whether all channels or only selected
channels are enabled and unmasked for transmission. For more details on how the channels are
affected, see
Transmit Multichannel Selection Modes
.
0
No transmit multichannel selection mode is on. All channels are enabled and unmasked. No
channels can be disabled or masked.
1h
All channels are disabled unless they are selected in the appropriate transmit channel enable
registers (XCERs). If enabled, a channel in this mode is also unmasked.
The XMCME bit determines whether 32 channels or 128 channels are selectable in XCERs.
2h
All channels are enabled, but they are masked unless they are selected in the appropriate transmit
channel enable registers (XCERs).
The XMCME bit determines whether 32 channels or 128 channels are selectable in XCERs.
3h
This mode is used for symmetric transmission and reception.
All channels are disabled for transmission unless they are enabled for reception in the appropriate
receive channel enable registers (RCERs). Once enabled, they are masked unless they are also
selected in the appropriate transmit channel enable registers (XCERs).
The XMCME bit determines whether 32 channels or 128 channels are selectable in RCERs and
XCERs.
