LM3S3748 Datasheet, PDF (215/753 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S3748 Microcontroller
Bit/Field
17:14
13:4
3
Name
ARBSIZE
XFERSIZE
NXTUSEBURST
Type
R/W
R/W
R/W
Reset
-
Description
Arbitration Size
Sets the number of DMA transfers that can occur before the controller
re-arbitrates. The possible arbitration rate settings represent powers of
2 and are shown below.
Value Description
0x0
1 Transfer
Arbitrates after each DMA transfer.
0x1
2 Transfers
0x2
4 Transfers
0x3
8 Transfers
0x4
16 Transfers
0x5
32 Transfers
0x6
64 Transfers
0x7
128 Transfers
0x8
256 Transfers
0x9
512 Transfers
0xA-0xF 1024 Transfers
This means that no arbitration occurs during the DMA transfer
because the maximum transfer size is 1024.
-
Transfer Size (minus 1)
Sets 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 controller updates this field immediately prior to it entering the
arbitration process, so it contains the number of outstanding DMA items
that are necessary to complete the DMA cycle.
-
Next Useburst
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 controller will use single transfers to complete
the transaction. If this bit is set, then the controller will only use a burst
transfer to complete the last transfer.
April 08, 2008
215
Preliminary