Raven. A homemade Atari-like computer

[agranlund]

@Oldskool, I managed to get hold of a 2MB card.
I think the old one might end up becoming a donor for building the Excelgraph card.

[PhilC]

@Oldskool, I managed to get hold of a 2MB card.
I think the old one might end up becoming a donor for building the Excelgraph card.

I'm hoping to have sourced the ram, DAC and maybe ferrite beads ready for five lots of cards.

[agranlund]

Playing with the CKBD firmware I noticed a flaw in the ckbd design.
The CH559 pin cannot turn on the IRF510 enough like a PIC can, so the eiffel-controlled fan header is essentially not working.

Changing the mosfet for a better suitable type is an option but since I want to board to act as a drop-in replacement for the PIC, and the original Eiffel schematic calls for IRF510, the fix will be a new version of the ckbd board.

It's possible to modify an existing board by soldering a resistor between FAN1 and +5V like so:
I picked a 1.8K resistor only because it was among the first of sensible value I found in my unorganised mess of through-hole resistors :)
Anything around that general area is probably fine.

ckbd_revc_fanfix.jpg

[agranlund]

For science :)

Let’s see if we can’t give revision.A2 some PWM support and an ARGB header like all those newfangled computers.

IMG_5005.jpeg

”Illuminated to extreme performance” :lol:

[viking272]

For science :)

Let’s see if we can’t give revision.A2 some PWM support and an ARGB header like all those newfangled computers.

”Illuminated to extreme performance” :lol:

Brilliant on both accounts esp PWM, not everyone's cup of tea but I'd use ARGB. Could you stretch to two headers of each?

[Oldskool]

Old vs new Raven:

raven.jpg

[agranlund]

This was quite fun actually!
Fan PWM and ARGB controlled by CH559.

Definitely putting modern fan headers on next motherboard rev.

IMG_5028.jpeg

[frank.lukas]

What about to Desgin a ISA to VME Interface to use a ATW800/2 ...?

[dml]

What about to Desgin a ISA to VME Interface to use a ATW800/2 ...?

That would be interesting. Raven & enclosure would make a good nest for a TRAM farm / development box :)

[viking272]

What about to Desgin a ISA to VME Interface to use a ATW800/2 ...?

They do seem to exist, so maybe a design exists that could help get a head start on developing one?
https://www.ebay.co.uk/itm/184646161942