82C237 Datasheet, PDF (14/25 Pages) Intersil Corporation – CMOS High Performance Programmable DMA Controller

82C237
CHANNEL
REGISTER
0
Base and Current Address
Current Address
Base and Current Word
Count
Current Word Count
1
Base and Current Address
Current Address
Base and Current Word
Count
Current Word Count
2
Base and Current Address
Current Address
Base and Current Word
Count
Current Word Count
3
Base and Current Address
Current Address
Base and Current Word
Count
Current Word Count
SIGNALS
FIRST/LAST DATA
FLIP-FLOP
BUS
OPERATION CS IOR IOW A3 A2 A1 A0
STATE
DB0-DB7
Write
0100000
0
A0-A7
0100000
1
A8-A15
Read
0010000
0
A0-A7
0010000
1
A8-A15
Write
0100001
0
W0-W7
0100001
1
W8-W15
Read
0010001
0
W0-W7
0010001
1
W8-W15
Write
0100010
0
A0-A7
0100010
1
A8-A15
Read
0010010
0
A0-A7
0010010
1
A8-A15
Write
0100011
0
W0-W7
0100011
1
W8-W15
Read
0010011
0
W0-W7
0010011
1
W8-W15
Write
0100100
0
A0-A7
0100100
1
A8-A15
Read
0010100
0
A0-A7
0010100
1
A8-A15
Write
0100101
0
W0-W7
0100101
1
W8-W15
Read
0010101
0
W0-W7
0010101
1
W8-W15
Write
0100110
0
A0-A7
0100110
1
A8-A15
Read
0010110
0
A0-A7
0010110
1
A8-A15
Write
0100111
0
W0-W7
0100111
1
W8-W15
Read
0010111
0
W0-W7
0010111
1
W8-W15
FIGURE 6. WORD COUNT AND ADDRESS REGISTER COMMAND CODES
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