rdlanctot@instr.okanagan.bc.ca (Ryan Lanctot) (02/03/89)
Here we go....
WARNING! I have not personally tried this out myself. Any problems you have
are solely your own. I take no responsibility for any possible
damages done as a result of using this circuit.
Now, on to the circuit.
DB19 male connector from last IIGS 3.5 drive.
\ /
\ /
----------------\ /---------------------/
1 1 1 1 1 1 1 1 1 1 pin 1-3 GND pin 11 PHI 0
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 pin 4 EN 3.5 pin 12 PHI 1
| | | | | | | | | | | | | | | | | | | pin 5 - 12V pin 13 PHI 2
------- | | --- | | | | | | | | | | | pin 6 + 5V pin 14 PHI 3
| | | | | | | | | | | | | | | pin 7,8 + 12V pin 15 WR REQ
| | | | | | | | | | | | | | | pin 9 EXT INT pin 16 HD SEL
| | | | | | | | | | | | | | | pin 10 WR PROT pin 17 DR1
| | | | | | | | | | | | | | | pin 18 RD DATA
| | | | | | | | | | | | | | | pin 19 WR DATA
| | | | | | | | | | | | | | |
1 -X----|-|--|--|-|-|-|-|-|-|-|-|-|-|--1
2 -|----|-|--|--|-|-X-|-|-|-|-|-|-|-|--2
3 -X----|-|--|--|-|---|-|-|-|-|-|-|-|--3
4 -|----|-|--|--|-|---X-|-|-|-|-|-|-|--4
5 -X----|-|--|--|-|-----|-|-|-|-|-|-|--5
6 -|----|-|--|--|-|-----X-|-|-|-|-|-|--6
7 -X----|-|--|--|-|-------|-|-|-|-|-|--7
8 ------|-|--|--|-|-------X-|-|-|-|-|--8
9 ------X-|--|--|-|---------|-|-|-|-|--9
10--------|--|--|-|---------X-|-|-|-|--10
11--------X--|--|-|-----------|-|-|-|--11
12--------X--|--|-|-----------|-|-|-|--12
13--------|--X--|-|-----------|-|-|-|--13
14--------|--|--X | | X-|-|--14
15--------|--X----|-----------|---|-|--15
16--------|--|----|-----------|---X-|--16
17--------|--X----|-----------|-----X--17
18--------|--|----|-----------|--------18
19--------|--X----|-----------|--------19
20--------|-------X-----------|--------20
^ | | ^
| -------\/\/\/-------- |
| 4.7 K |
|- 20 PIN MALE HEADER TO DRIVE #2 |- 20 PIN MALE HEADER TO DRIVE #1
This cable lets you daisy chain your old 5.25 drives onto your 3.5 GS drives
> Note particularily that pin 4 must be grounded and a pullup resistor
> is recommended as shown. Also be VERY CAREFUL to use shrouded or otherwise
> restrained connectors. If you wrongly plug a 5.25 drive in so it is offset
> by one pin or by one row, you can instantly DESTROY several drives and the
> IIGS motherboard
and then he goes on to say that the cables (adaptors) can be had from
Redmond Cable, which is in washington state, I believe.
The above circuit was taken directly from Computer Shopper, June 1988 issue
page 192. Author: Don Lancaster. I also think this circuit is in his
Ask the Guru reprints, but I'm not sure.
Ryan Lanctot
<RDLANCTOT@instr.okanagan.bc.ca>
"Your mother's ugly and you dress her funny - a new twist on an old saying!"
:)