18 Feb
2006
18 Feb
'06
4:23 p.m.
On 2/18/2006 at 6:04 PM Kelly Leavitt wrote:
It current has two options for the floppy controller:
3F0-3F7h or 370-377h
3F0 (001111110000) is with J8/1 open
370 (001101110000) is with J8/1 closed
Are you sure that the jumper isn't J7? According to my refs, J8 is
enable/disable floppy.
I don't have the 1542B, but I do have a 1542A, which is a
less-well-integrated version (uses an 8085). On mine, the floppy address
is decoded using a 74LS688 magnitude comparator, so it would be easy to
change, buf that much of the address selection wiring is UNDER the SMT
package, so it would have to be unsoldered. But once that was done, it
would be a pretty simple job to change the address.
I don't know if the 1542B is that simple-minded, though--Adaptec could have
gotten smart and used a PAL or even an ASIC for some of that.
Cheers,
Chuck