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Re: Raven. A homemade Atari-like computer
Posted: 05 Jul 2025 18:10
by PhilC
@Oldskool you need a 2mb card and it yo be wired correctly for that to work.
Hopefully the new card I'm building will do it.
Re: Raven. A homemade Atari-like computer
Posted: 06 Jul 2025 10:21
by 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.
Re: Raven. A homemade Atari-like computer
Posted: 06 Jul 2025 10:48
by PhilC
agranlund wrote: 06 Jul 2025 10:21
@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.
Re: Raven. A homemade Atari-like computer
Posted: 06 Jul 2025 10:50
by 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 1271 times
Re: Raven. A homemade Atari-like computer
Posted: 07 Jul 2025 19:02
by 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 1211 times
”Illuminated to extreme performance” :lol:
Re: Raven. A homemade Atari-like computer
Posted: 08 Jul 2025 11:33
by viking272
agranlund wrote: 07 Jul 2025 19:02
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?
Re: Raven. A homemade Atari-like computer
Posted: 08 Jul 2025 11:59
by Oldskool
Old vs new Raven:
- raven.jpg (36.57 KiB) Viewed 1166 times
Re: Raven. A homemade Atari-like computer
Posted: 08 Jul 2025 23:59
by 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 1124 times
Re: Raven. A homemade Atari-like computer
Posted: 09 Jul 2025 09:14
by frank.lukas
What about to Desgin a ISA to VME Interface to use a ATW800/2 ...?
Re: Raven. A homemade Atari-like computer
Posted: 09 Jul 2025 09:23
by dml
frank.lukas wrote: 09 Jul 2025 09:14
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 :)