Datasheet 479
LPC Interface Bridge Registers (D31:F0)
13.2.7 DMACH_MODE—DMA Channel Mode Register
I/O Address: Ch. #0–3 = 0Bh;
Ch. #4
–7 = D6h Attribute: WO
Default Value: 0000 00xx Size: 8-bit
Lockable: No Power Well: Core
Bit Description
7:6
DMA Transfer Mode — WO. Each DMA channel can be programmed in one of four
different modes:
00 = Demand mode
01 = Single mode
10 = Reserved
11 = Cascade mode
5
Address Increment/Decrement Select — WO. This bit controls address increment/
decrement during DMA transfers.
0 = Address increment. (default after part reset or Master Clear)
1 = Address decrement.
4
Autoinitialize Enable — WO.
0 = Autoinitialize feature is disabled and DMA transfers terminate on a terminal count.
A part reset or Master Clear disables autoinitialization.
1 = DMA restores the Base Address and Count registers to the current registers
following a terminal count (TC).
3:2
DMA Transfer Type — WO. These bits represent the direction of the DMA transfer.
When the channel is programmed for cascade mode, (bits[7:6] = 11) the transfer type
is irrelevant.
00 = Verify – No I/O or memory strobes generated
01 = Write – Data transferred from the I/O devices to memory
10 = Read – Data transferred from memory to the I/O device
11 = Invalid
1:0
DMA Channel Select — WO. These bits select the DMA Channel Mode Register that
will be written by bits [7:2].
00 = Channel 0 (4)
01 = Channel 1 (5)
10 = Channel 2 (6)
11 = Channel 3 (7)
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