Using Two Partitions
Multichannel Selection Modes
5-6
SPRU592E
1 shows an example of alternating between the channels of partition
A and the channels of partition B. Channels 0-15 have been assigned to
partition A, and channels 16-31 have been assigned to partition B. In response
to a frame-sync pulse, the McBSP begins a frame transfer with partition A and
then alternates between partitions B and A until the complete frame is
transferred.
Figure 5
−
1. Alternating Between the Channels of Partition A and the Channels of
Partition B
0-15
16-31
0-15
16-31
0-15
16-31
0-15
16-31
0-15
Block
Channels
FS(R/X)
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
0
1
0
1
0
1
0
1
0
Partition
A
B
A
B
A
B
A
B
A
2-partition mode. Example with fixed block assignments
As explained next, you can dynamically change which blocks of channels are
assigned to the partitions.
5.4.2 Reassigning Blocks During Reception/Transmission
If you want to use more than 32 channels, you can change which channel
blocks are assigned to partitions A and B during the course of a data transfer.
However, these changes must be carefully timed. While a partition is being
transferred, its the associated block assignment bits cannot be modified, and
its associated channel enable register cannot be modified. For example, if
block 3 is being transferred and block 3 is assigned to partition A, you cannot
modify (R/X)PABLK to assign different channels to partition A, and you cannot
modify (R/X)CERA to change the channel configuration for partition A. Several
features of the McBSP help you time the reassignment:
-
The block of channels currently involved in reception/transmission (the
current block) is reflected in the RCBLK/XCBLK bits. Your program can
poll these bits to determine which partition is active. When a partition is not
active, it is safe to change its block assignment and channel configuration.
-
At the end of every block (at the boundary of two partitions), an interrupt
can be sent to the CPU. In response to the interrupt, the CPU can then
check the RCBLK/XCBLK bits and update the inactive partition.
Summary of Contents for TMS320VC5509
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Page 43: ...McBSP Operation 2 20 SPRU592E This page is intentionally left blank ...
Page 105: ...SPI Operation Using the Clock Stop Mode 6 16 SPRU592E This page is intentionally left blank ...
Page 187: ...Transmitter Configuration 8 40 SPRU592E This page is intentionally left blank ...
Page 191: ...General Purpose I O on the McBSP Pins 9 4 SPRU592E This page is intentionally left blank ...
Page 201: ...Emulation Power and Reset Considerations 10 10 SPRU592E ...
Page 207: ...Data Packing Examples 11 6 SPRU592E This page is intentionally left blank ...
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