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 (94.43 KiB) Viewed 421 times

[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 (827.98 KiB) Viewed 361 times

”Illuminated to extreme performance”

[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”

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 (36.57 KiB) Viewed 316 times

[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 (463.97 KiB) Viewed 274 times

[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