-- Lark8237.txt
-- L. Stewart December 21, 1981 12:03 PM
Audio DMA: Port 1x
Encrypt DMA: Port 4x
Audio DMA:
Channel Use
----------------------------
0 Audio Input
1 Audio Output
2 Zeros
3 Unused
Encrypt DMA:
Channel Use
----------------------------
0 Audio DMA (cascade)
1 SLC (cascade)
2 Enc. Master
3 Enc. Slave
Both DMA controllers set up for:
High true request lines
Low true acknowledge lines
Fixed priority, channel 0 highest
Ports:
Audio Enc. Read Write
--------------------------------
18 48 Status Command
19 49 --- Request
1A 4A --- Single mask bit
1B 4B --- Mode registers
1C 4C --- Clear byte pointer
1D 4D Temp Master Clear
1E 4E --- ---
1F 4F --- Write all mask bits
Word registers (write low byte first)
Channel 0
10 40 Addr Base Addr
11 41 Count Base Count
Channel 1
12 42 Addr Base Addr
13 43 Count Base Count
Channel 2
14 44 Addr Base Addr
15 45 Count Base Count
Channel 3
16 46 Addr Base Addr
17 47 Count Base Count
Command register:
20 DAck low, DReq high, extended write,
fixed priority, normal reads, controller
enable, ch. 0 normal, BLT disabled
Mode Register
0 | Channel select
1 | "
2 | 00: Verify 01: Write
3 | 10: Read 11: illegal
4 Autoinitialize
5 Address Decrement
6 | 00: Demand 01: Single
7 | 10: Block 11: Cascade
Program Enc DMA to cascade channel 0 only
-- Master reset both controllers
O4D,00
O1D,00
-- Set both command registers
O48,20
O18,20
-- Set mode registers
-- ch. 0 AND 1 cascade, 2 read, 3 write
O4B,C0,C1,4A,47
-- all auto, single, write, read, write, ch. 3 read
O1B,54,59,56,4B
-- Audio addresses
-- clear byte pointer
O1C,00
-- Ch 0 (input) address
O10,00,80
O11,00,02
-- Ch 1 (output) address
O12,00,80
O13,00,02
-- Ch 2 (zeros)
O14,00,80
O15,00,02
Enable requests
-- Enc DMA channel 0, 1 only
O4F,0C
-- Audio DMA, channels 0, 1, 2
O1F,08
-- Whole thing, for stuffing
O4D,00
O1D,00
O48,20
O18,20
O4B,C0,C1,4A,4B
O1B,54,59,56,4B
O1C,00
O10,00,80
O11,00,08
O12,00,80
O13,00,08
O14,00,80
O15,00,08
O4F,0C
O1F,08
-- remember to set up 9513 first
-- Alternative, for 1/2 second echoing
O4F,0F
O1F,0F
O4D,00
O1D,00
O48,20
O18,20
O4B,C0,C1,4A,47
O1B,54,59,56,4B
O1C,00
O10,00,08
O11,00,10
O12,04,08
O13,00,10
O14,04,08
O15,00,10
O4F,0C
O1F,08