milliga@cat2.cs.wisc.edu (Michael Milligan) (03/02/91)
I'm trying to come up with schematics to fabricate an expansion board to SOTS
my A500 (i.e. give it Zorro II slots just like the 2000). I notice that the
86 pin expansion bus contains almost all the signals available from the Zorro
II slots, so it seems that it can be done without too much difficulty. . .
Strangely, I don't have access to 2000 schematics, so it makes things a little
hairy. I do have access to someone's 3000 shcematics, which indicate to me
that it's necessary to do address and data buffering as well as add a circuit
to handle the auto-configuration. The information I'm missing has to do with
the functions of the Fat Buster chip. Could someone please clarify to me how
it works in relation to the Zorro slots (and only for Zorro II boards)?
Thanks in advance,
from one frustrated individual
--
"I'm wasted, and I can't shutup!" | Michael Milligan, Professional Student
-- saying on a chars T-shirt from | "Nothing I say can or will be used
cartoon Badgers & Other Animals | against me in a court of law."vincelee@tornado.Berkeley.EDU (Vincent H. Lee) (03/06/91)
In article <1991Mar1.210755.16835@daffy.cs.wisc.edu> milliga@cat2.cs.wisc.edu (Michael Milligan) writes: >I'm trying to come up with schematics to fabricate an expansion board to SOTS >my A500 (i.e. give it Zorro II slots just like the 2000). I notice that the >86 pin expansion bus contains almost all the signals available from the Zorro >II slots, so it seems that it can be done without too much difficulty. . . > This is actually very easy. I have one such circuit in my 500. Simply connect the 86 pins to the first 86 pins of the ZorroII Slot... Really. Then, connect RES (86) to RESB (94). If your device needs a 7Mhz clock, input C3(14) and C5 (16) to an Xor gate. Invert the output, and connect to 7ME (92). That's it! -Vince .
milliga@cat4.cs.wisc.edu (Michael Milligan) (03/07/91)
In article <1991Mar6.104401.18859@agate.berkeley.edu> vincelee@tornado.Berkeley.EDU (Vincent H. Lee) writes: > > This is actually very easy. I have one such circuit in my 500. > > Simply connect the 86 pins to the first 86 pins of the ZorroII Slot... Really. > Then, connect RES (86) to RESB (94). If your device needs a 7Mhz clock, > input C3(14) and C5 (16) to an Xor gate. Invert the output, and connect to > 7ME (92). That's it! > > -Vince > . This isn't quite what I had in mind. I'd like to put together a board that has at least 2 Zorro II slots, so I'm still in need of information on handling bus mastering, buffering, etc. . . I basically need information on how the Buster chip in the A2000 (I think that's the chip) and/or the PAL's work to handle multiple expansion cards. I don't have access to A2000 schematics, which is why I need this info. I had planned to pull the 7M signal right off the motherboard since Agnus spits it out. . . No sense in having a circuit to do something redundant. -- "I'm wasted, and I can't shutup!" | Michael Milligan, Professional Student -- saying on a chars T-shirt from | "Nothing I say can or will be used cartoon Badgers & Other Animals | against me in a court of law."
monty@sagpd1 (03/22/91)
In article <1991Mar6.222406.11851@daffy.cs.wisc.edu> milliga@cat4.cs.wisc.edu (Michael Milligan) writes: >the chip) and/or the PAL's work to handle multiple expansion cards. I don't >have access to A2000 schematics, which is why I need this info. ^^^^^^^^^^^^^^^^^ Available from CATS for $40.00 Monty Saine