Lattice Semiconductor ispLever Core Multi-Channel DMA Controller, User Manual, Page: 19 / 29

Lattice Semiconductor Multi-Channel DMA Controller User’s Guide
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Table 7. Mode Register - 8237 Mode
Table 8. Mask Register: Access All Bits - 8237 Mode
Table 9. Mask Register: Access One Bit - 8237 Mode
Table 10. Request Register: Access One Bit - 8237 Mode
Bit Description
1:0 00 Channel 0 select
01 Channel 1 select
10 Channel 2 select
11 Channel 3 select
3:2 00 Verify transfer
01 Write transfer
10 Read transfer
11 Illegal
xx
If bits 6 & 7 are 11
4 0 Auto-initialization disable
1 Auto-initialization enable
5 0 Address increment
1 Address decrement
7:6 10 Demand mode select
01 Single mode select
10 Block mode select
11 Cascade mode (unsupported)
Bit Description
0 0 Channel 0 unmasked
1 Channel 0 masked
1 0 Channel 1 unmasked
1 Channel 1 masked
2 0 Channel 2 unmasked
1 Channel 2 masked
3 0 Channel 3 unmasked
1 Channel 3 masked
Bit Description
1:0 00 Select channel 0 mask bit
01 Select channel 1 mask bit
10 Select channel 2 mask bit
11 Select channel 3 mask bit
2 0 Clear mask bit
1 Set mask bit
7:3 Don’t care
Bit Description
1:0 00 Select channel 0 request bit
01 Select channel 1 request bit
10 Select channel 2 request bit
11 Select channel 3 request bit
2 0 Clear request bit
1 Set request bit
7:3 Don’t care