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/
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Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Bit field
Name
Description
100000: The maximum number of data transfers is 32
Other: reserved
16
FB
Fixed burst bit.
This bit controls whether the AHB master interface performs fixed burst length
transfers.
0: AHB uses only SINGLE and INCR data transfer operations during continuous
transfer.
1: AHB uses SINGLE, INCR4, INCR8 and INCR16 data transfer operations during
continuous transfer.
15:14
PR[1:0]
Receive and transmit priority ratio.
These bits represent the access priority ratio between RxDMA and TxDMA.
00: RxDMA:TxDMA = 1:1
01: RxDMA:TxDMA = 2:1
10: RxDMA:TxDMA = 3:1
11: RxDMA:TxDMA = 4:1
Note: This bit is only valid when the DMA arbitration mode is cyclic mode
(ETH_DMABUSMOD.DA = 0).
13:8
PBL[5:0]
Programmable burst length.
These bits define the maximum number of data transfers for one DMA transfer. If
ETH_DMABUSMOD.USP = 1, these bits are only used for TxDMA transfers. If
ETH_DMABUSMOD.USP = 0, these bits are used for both TxDMA and RxDMA
transfers.
000001: The maximum number of data transfers is 1
000010: The maximum number of data transfers is 2
000100: The maximum number of data transfers is 4
001000: The maximum number of data transfers is 8
010000: The maximum number of data transfers is 16
100000: The maximum number of data transfers is 32
Other: reserved
7
Reserved
Reserved, the reset value must be maintained.
6:2
DSL[4:0]
Descriptor skip length.
These bits define the jump distance between 2 descriptors connected in a ring
structure, in words (32 bits). Address jump refers to the address difference from the
end of the current descriptor to the beginning of the next descriptor.
1
DA
DMA arbitration bit.
This bit indicates the arbitration mode between TxDMA and RxDMA.
0: Arbitrate in a round-robin manner according to the value of these bits in
ETH_DMABUSMOD.PR[1:0].
1: Fixed priority mode, the priority of receiving is higher than that of sending.
0
SWR
Software reset.
0: No effect
1: Reset the internal registers and logic circuits of all subsystems of ETH. After the