Texas Instruments OMAP5912 Reference Manual page 1672

5 Multichannel Selection Modes
5.1 Channels, Blocks, and Partitions
5.2 Multichannel Selection
SPRU762B
This section discusses the multichannel selection modes for the McBSP.
A McBSP channel is a time slot for shifting in/out the bits of one serial word.
Each McBSP supports up to 128 channels for reception and 128 channels for
transmission.
In the receiver and in the transmitter, the 128 available channels are divided
into eight blocks that each contain 16 contiguous channels:
Block 0: Channels 0–15
Block 1: Channels 16–31
Block 2: Channels 32–47
Block 3: Channels 48–63
The blocks are assigned to partitions according to the selected partition mode.
In the two-partition mode (described in section 5.4), you assign one
even-numbered block (0, 2, 4, or 6) to partition A and one odd-numbered block
(1, 3, 5, or 7) to partition B. In the 8-partition mode (described in section 5.5),
blocks 0 through 7 are automatically assigned to partitions A through H,
respectively.
The number of partitions for reception and the number of partitions for
transmission are independent. For example, it is possible to use two receive
partitions (A and B) and eight transmit partitions (A–H).
When a McBSP uses a time-division multiplexed (TDM) data stream while
communicating with other McBSPs or serial devices, the McBSP may need to
receive and/or transmit on only a few channels. To save memory and bus
bandwidth, you can use a multichannel selection mode to prevent data flow
in some of the channels.
Each channel partition has a dedicated channel enable register. If the
appropriate multichannel selection mode is on, each bit in the register controls
whether data flow is allowed or prevented in one of the channels that is
assigned to that partition.
The McBSP has one receive multichannel selection mode (described in
section 5.6) and three transmit multichannel selection modes (described in
section 5.7).
Multichannel Selection Modes
Block 4: Channels 64–79
Block 5: Channels 80–95
Block 6: Channels 96–111
Block 7: Channels 112–127
Multichannel Buffered Serial Ports (McBSPs) 61