The bus is on the way...

[BillO]

Ive got a cool new device on the way from PCB fabrication:

BUS.png (43 KiB) Viewed 8992 times

It's a 4 slot back plane for 600 board based computers. I'll provide more details once it checks out, but it's designed primarily for I/O, not memory. Each slot is assigned a location between E000 and E7FF and each slot can address 4 devices with only using a 74SL32 to provide device selects for each device. But there are 7 address lines brought out to the bus, so you could theoretically have 512 devices per slot.

I've got 5 coming, but if they work I'll only ever need 2 of them. Is anyone interested in one of the surplus items? I'll be getting a few different design prototyping boards for the bus too.

[Jeff]

Cool!!!!!!!

[BillO]

It has arrived and been tested.

However, I had already thought of changes before it arrived, and I had forgotten to handle the data direction issue -- so I had sent off the updated design before these ones got to my door.

Nonetheless, the bodge to fix the data direction is simple and I built one up to develop and debug the glue GAL code, and ... it works! (yes, I love GALs. Not afraid to admit it)

I'll post some pictures and more information tomorrow or Sunday. I'm quite pleased with the result and the updated version will be even better.

[BillO]

Sorry for the delay on this, but the pandemic has been at play. I have my revised board in and am building up a sample. will update shortly.

[BillO]

So, here it is:

Bare board

IMGP9815.JPG (148.87 KiB) Viewed 8451 times

Fully populated

IMGP9816.JPG (138.51 KiB) Viewed 8451 times

And connected up to My Klyball 600D though one of my memory expansion cards.

Connected

IMGP9820.JPG (162.18 KiB) Viewed 8451 times

The prototype card in it is an analog card with an ADC and a DAC made up for another project on a different machine. This machine:

Jaguar

IMGP9695.JPG (167.53 KiB) Viewed 8451 times

It is also a 6502 machine but can and has run at 16MHz using the W65C02S. The OSI bus you see above is compatible with the bus on that machine so that interfaces built for one should, with some minor exceptions, run on the other.

One of the first projects I have in mind for the OSI bus is a game card containing an SN76489AN sound chip (used in many a machine of the day) and dual C64 compatible joystick ports. The sound portion has been prototyped already and here is a sample of the sound it can produce:

Lavender's Blue.zip

Audio card sample

(370.66 KiB) Downloaded 651 times

[BillO]

Unfortunately I have had to go back to work so little has gotten done with my plans for this. Maybe winter will afford me some more spare time.

On another note, I was hoping there would be more interest in this so that I would not be the only one developing new gadgets. In any case, I still do have a couple of extra boards if anyone ever develops some interest. It would be neat to have a team effort - more minds more fruit.

[dave]

Really nice work, Bill!

I would be interested in playing around with one of these. As with you, time is limited and I have a pretty big backlog of projects but this would definitely make the list!

Dave

[BillO]

Hi Dave,

PM me a mailing address. I'd be happy to send one to you as my thanks for keeping this site going.

Have a great holiday season!