DescriptionResetTypeNameBit/Field
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 μDMA 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 μDMA cycle.
-RWXFERSIZE13:4
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 μDMA 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.
-RWNXTUSEBURST3
μDMA Transfer Mode
This field configures the operating mode of the μDMA cycle. Refer to
“Transfer Modes” on page 685 for a detailed explanation of transfer
modes.
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.
DescriptionValue
Stop0x0
Basic0x1
Auto-Request0x2
Ping-Pong0x3
Memory Scatter-Gather0x4
Alternate Memory Scatter-Gather0x5
Peripheral Scatter-Gather0x6
Alternate Peripheral Scatter-Gather0x7
-RWXFERMODE2:0
XFERMODE Bit Field Values.
Stop
Channel is stopped or configuration data is invalid. No more transfers can occur.
Basic
For each trigger (whether from a peripheral or a software request), the μDMA controller performs
the number of transfers specified by the ARBSIZE field.
Auto-Request
The initial request (software- or peripheral-initiated) is sufficient to complete the entire transfer
of XFERSIZE items without any further requests.
June 18, 2014708
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
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