Registers
1253
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multichannel Buffered Serial Port (McBSP)
Table 25-29. Multichannel Control Register (MCR) Field Descriptions (continued)
Bit
Field
Value
Description
17-16
XMCM
0-3h
Transmit multichannel selection mode bit. XMCM determines whether all channels or only selected
channels are enabled and unmasked for transmission.
0
Transmit multichannel selection is off. 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 enhanced transmit channel enable
register (XCERE
n
). If enabled, a channel in this mode is also unmasked.
The XMCME bit determines whether 32 channels or 128 channels are selectable in XCERE
n
.
2h
All channels are enabled, but they are masked unless they are selected in the appropriate enhanced
transmit channel enable register (XCERE
n
).
The XMCME bit determines whether 32 channels or 128 channels are selectable in XCERE
n
.
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
enhanced receive channel enable register (RCERE
n
). Once enabled, they are masked unless they are
also selected in the appropriate enhanced transmit channel enable register (XCERE
n
).
The XMCME bit determines whether 32 channels or 128 channels are selectable in RCERE
n
and
XCERE
n
.
15-10
Reserved
0
Reserved.
9
RMCME
Receive multichannel partition mode bit. RMCME is only applicable if channels can be individually
disabled/enabled for reception (RMCM = 1). RMCME determines whether only 32 channels or all 128
channels are to be individually selectable.
0
2-partition mode. Only partitions A and B are used. You can control up to 32 channels in the receive
multichannel selection mode (RMCM = 1).
Assign 16 channels to partition A with the RPABLK bit and assign 16 channels to partition B with the
RPBBLK bit.
You control the channels with the enhanced receive channel enable register partition A/B (RCERE0).
1
You can control up to 128 channels in the receive multichannel selection mode.
You control the channels with the appropriate enhanced receive channel enable register (RCERE
n
):
RCERE0: Channels 0 through 31
RCERE1: Channels 32 through 63
RCERE2: Channels 64 through 95
RCERE3: Channels 96 through 127
8-7
RPBBLK
0-3h
Receive partition B block bit.
RPBBLK is only applicable if channels can be individually disabled/enabled (RMCM = 1) and the 2-
partition mode is selected (RMCME = 0). Under these conditions, the McBSP receiver can accept or
ignore data in any of the 32 channels that are assigned to partitions A and B of the receiver.
The 128 receive channels of the McBSP are divided equally among 8 blocks (0 through 7). When
RPBBLK is applicable, use the RPBBLK bit to assign one of the odd-numbered blocks (1, 3, 5, or 7) to
partition B; use the RPABLK 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 receiver 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 RCBLK bit is regularly updated to indicate which block is active.
When XMCM = 3h (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