Texas Instruments CC3200 Technical Reference Manual page 114

Register Description
Table 4-8. DMA_CHCTL Register Field Descriptions (continued)
Bit Field
17-14 ARBSIZE
13-4 XFERSIZE
3 NXTUSEBURST
2-0 XFERMODE
114
Direct Memory Access (DMA)
Type Reset Description
R/W 0h This field configures the number of transfers that can occur before
the DMA controller re-arbitrates. The possible arbitration rate
configurations represent powers of 2 and are shown below.
0xA-0xF = 1024 transfer
0h = 1 transfer
1h = 2 transfer
2h = 4 transfer
3h = 8 transfer
4h = 16 transfer
5h = 32 transfer
6h = 64 transfer
7h = 128 transfer
8h = 256 transfer
R/W 0h Transfer Size (minus 1). This field configures the total number of
items to transfer. The value of this field is 1 less than the number to
transfer (value 0 means transfer 1 item). The maximum value for this
10-bit field is 1023 which represents a transfer size of 1024 items.
The transfer size is the number of items, not the number of bytes. If
the data size is 32 bits, then this value is the number of 32-bit words
to transfer.
The DMA controller updates this field immediately prior to entering
the arbitration process, so it contains the number of outstanding
items that is necessary to complete the DMA cycle
R/W 0h Next Useburst. This field controls whether the Useburst SET[n] bit is
automatically set for the last transfer of a peripheral scatter gather
operation.
Normally, for the last transfer, if the number of remaining items to
transfer is less than the arbitration size, the DMA controller uses
single transfers to complete the transaction.
If this bit is set, then the controller uses a burst transfer to complete
the last transfer.
R/W 0h DMA Transfer Mode. This field configures the operating mode of the
DMA cycle. Because this register is in system RAM, it has no reset
value. Therefore, this field should be initialized to 0 before the
channel is enabled.
0h = Stop
1h = Basic
2h = Auto-request
3h = Ping-pong
4h = Memory Scatter-Gather
5h = Alternate memory scatter gather
6h = Peripheral scatter gather
7h = Alternate peripheral scatter gather
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SWRU367D – June 2014 – Revised May 2018
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