GVP A500-HD+ and GVP A530 Mini Slot - Zorro2 Capable?

[darksun9210]

so, while working from home today i had a bit of time to chase up on something i was mucking about with ages ago.

the GVP A500 add-ons have a "mini-slot" and no one seemed to have any details on the 100 pin connector on the board. so i buzzed it out today seeing what pin was what; in relation to the 86pin expansion header.

turns out its almost a complete carbon copy pin for pin of the expansion header and therefore Z2 slot, except the 5volt and 12volt power comes off it's own power supply, be that external, or switched to be fed from the amiga itself.

now the only lines that didn't buzz out are the following, 7, 8, 9. then 11, and 12;- those pins are 7Mhz/NC, -12V, NC, then the zorro CFGin and CFGout lines
Then 15, 18, 20, and 22:- CDAC, XRDY, -12V, INT6 respectively
next up are 31, 33, 35, then 40, 42, 44, 48:- FC0, FC1, FC2, and IPL0, IPL1, IPL2, and VPA again respectively.
next ones are 50, 51, 53, 55:- so thats, eClock, VMA, RST, HLT.

then that's it till pins 91 to 98 which i can't get anything out of, and 87, 88, 89, 90, 99 and 100 are ground lines - just like Zorro 2.

so i'm willing to bet some of those are handled by some buffers or logic somewhere, hence not buzzing through directly. and for whatever's left, how much could a Z2 slot lose out of these and still be functional?

from the pin header of the board, it looks like you could pretty much just wire a zorro slot straight to it, plug in a card and off you go? almost like, why didn't GVP do that from the beginning, unless a pin header is cheaper than a slot....?

[Oldsmobile_Mike]

I'm waiting for someone to hack a Zorro card to fit on top of the sidecar.   

[darksun9210]

yeah that's kinda been my dream too since either my Supra28+A500-HD+ combo, and then eventually A530 was my main system. it was a bit of a kludge to have a clock port adapter, subwayUSB, and then a USB ethernet NIC to get connected. but it worked like a little champ. just it wasn't pretty!

so i got a zorro2 right angle adapter and a kickflash as "cheap/expendable" zorro2 card (if there is such a thing). unfortunatly to get the pins lined up, the right angle adaptor i have points the card into the side of the A500 instead of keeping it inside the case of the GVP sidecar, and pin 1 is at the back of the case, so from what i figure the cards will be mounted backwards as you look at the frankenmachine setup

as such, and as was probably garrenteed to happen, my temporary zorro hook-up got knocked and i think the kickflash got 5volts somewhere it shouldn't; as it's now not visible in either of my other zorro equipped machines as a working device. the GVP's are fine though.

so i'll revise my connection to
1. be a bit more stable/reliable/not move.
2. double check my pin connections.
3. spin the slot/card round to face front
4. have it laying the right way in the sidecar
5. find another way to test without potentially zapping a rare bit of kit.

i figure a half length zorro card should fit inside the GVP sidecar with a flash based scsi drive...? maybe even two cards with staggered slot positions....?

[darksun9210]

So, i stuck a bit of gold today.

all thanks to a Mr Peter Ray, whoever you are, i thank you. Peter did some work on getting a Picasso2 card to work off the A500 expansion slot.

http://web.tiscali.it/peterray/zorro2slot.html

i've splatted the link to save duplicating, but basically it works out that pretty much all of the lines i couldn't buzz out and trace above, are not needed anyway, or are handled by logic.

so most of today i've been routing a purely passive board to sit on the GVP's mini slot and give me 2 staggered zorro2 slots - mainly just to see if it'll fit in the GVP case. the first board i'll make, i'll have it switchable to have either, one; or if by shear luck, two slots active just by jumpering the cfgin/out pins to skip the second slot - keep it simple.
i'm on my 4th board route as i'm learning as i go, but i'll see if i can get only a few of the female 100 pin headers, to build this with, instead of "by the hundred" i'm getting offered at the moment.

i don't know if i'll need to make it active/smart some form of logic on there. but baby steps.

[darksun9210]

So, this is what i got so far.
any thoughts or suggestions welcome! the idea is this stands vertically up from the pin header and provides a couple of horizontal z2 slots.

hmmm, my picture thing didn't work. so i've uploaded it into the A500 gallery

[Munchkin]

Is that the same slot as in the GVP HD8+ SCSI controller for the A500, right?

If so whatever you come up with should work in that as well. I've been thinking about this a long time actually, that it should be possible to make use of that slot for something else. I'm not a hardware tinkerer though so I've never done any research about it.

Would be great to have that converted to a ZII slot though, so many options opens up then.

Downside I guess is that it's not very practical to have a card sit so close to the keyboard.

I doubt that you will be able to make 2 working slots though, not without some kind of buffering at least and since there's no Buster in an A500 it's probably gonna be difficult to get  two cards to work together, if at all. I gather that's the reason the Checkmate only has one zorro slot, it's just not possible to make two slots work properly.

[darksun9210]

Ah good info.
I've drawn up the board so the Zorro slots are facing "inside" the GVP case - though you'll probably have to 3D print a new lid for the GVP to cope with any full length zorro cards poking out the back

i'll draw up a new riser, only i'll wind my neck in a bit and do a simple single slot first - even though i've got a slot bypass on my current design - if it saves me soldering an extra 100 pins to find it's never going to work, it's worth it i guess.

also wondering if i can butcher a clock port and/or a simple IDE controller in there too without too much effort. am also temped to ask Jens what he's using to interface his little ethernet module for the ACA500... ideas idea and more ideas.... spec creep! 

[Motormouth]

For the opposite configuration, could you use a GVP 286 in a zorro II slot?