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Re: Raven. A homemade Atari-like computer
Posted: 09 Jul 2025 09:31
by viking272
frank.lukas wrote: 09 Jul 2025 09:14
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
Re: Raven. A homemade Atari-like computer
Posted: 09 Jul 2025 15:53
by frank.lukas
ISA are 16bit and the Atari single VME Bus are 16bit too. VME is a 68k Bus ...
Re: Raven. A homemade Atari-like computer
Posted: 12 Jul 2025 10:14
by agranlund
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 neat, I'd buy it :)
Re: Raven. A homemade Atari-like computer
Posted: 12 Jul 2025 10:43
by agranlund
It doesn't happen too often but I sat down to have fun with KiCad.
I see traces everywhere now :)
- a2wip_250712.png (1.32 MiB) Viewed 1471 times
I stumbled upon a flaw with the realtime clock on the current board.
It'll go to battery backup mode when the power is turned off, as opposed to when the power plug is disconnected, draining the battery when it doesn't have to.
Has been fixed for rev.A2 but there's no super-easy way to patch it on current revisions.
(you'd want pin8 of U406 to receive +5VL standby power from the ATX power connector instead of the regular +5V)
Re: Raven. A homemade Atari-like computer
Posted: 12 Jul 2025 12:21
by PhilC
Hinting, remember there's plenty of room to move the 68150 to make soldering the buffers easier.
Were you going to add a network chip this time?
Re: Raven. A homemade Atari-like computer
Posted: 12 Jul 2025 18:01
by agranlund
PhilC wrote: 12 Jul 2025 12:21
Were you going to add a network chip this time?
Yes, it currently has one and I removed the PS/2 port in favour of a stacked USB + Ethernet port.
- Screenshot 2025-07-12 at 17.21.20.png (366.59 KiB) Viewed 1424 times
All in all it's only a small and final(??) iterative update on the Ax revision.
So far, and subject to changes-on-a-whim as usual :)
Code: Select all
Silkscreen: Fixed wrong pinout info for J305
Silkscreen: Reversed order of RAM simms
Silkscreen: Clearer orientation for a bunch of headers
Silkscreen: Clearer pin1 markers for a bunch of SMD footprints
Footprint: Larger footprints for handsolder D201, D202, D203
BOM: Replaced PLCC64 socket for U104 with black part
BOM: Replaced PLCC84 socket for U108 with black part
BOM: Replaced buttons SW101,SW201,SW202 with black parts
BOM: Changed C310 to 0.1uF (was 0.01uF)
Replaced through-hole DS1818 with DS1818R (SMD version)
Fixed RTC power delivery, now using ATX standby power
Added small solderpad for securing Y402 to board
Added 68150:BUSCS signal separate from 68150:CS
Added pullups on 68150 data bus
Added pulldown on IDE:IRQ
Added i2c eprom with preprogrammed MAC address
Added i2c expansion header
Added internal USB header (two ports)
Added W5100s ethernet controller
Replaced Eiffel with CKBD
Replaced 2xPS2 connector with 2xUSB + Ethernet
CPU temperature sensor to CKBD
PowerOff control from CKBD
PowerSwitch status can be read through XR68M752 (detect powerbutton held down during boot)
Replaced one 12V fan header with PWM + ARGB
Changed IDE interface to big endian as standard on Atari machines
Re: Raven. A homemade Atari-like computer
Posted: 12 Jul 2025 18:41
by PhilC
Nice update. Are you planning to build one?
Re: Raven. A homemade Atari-like computer
Posted: 12 Jul 2025 18:45
by exxos
agranlund wrote: 12 Jul 2025 10:43
It doesn't happen too often but I sat down to have fun with KiCad.
I see traces everywhere now :)
Looks good :) Someone has a lot of patience :P
Re: Raven. A homemade Atari-like computer
Posted: 13 Jul 2025 23:10
by agranlund
PhilC wrote: 12 Jul 2025 18:41
Nice update. Are you planning to build one?
Oh yes, but I'm not fully sure when yet.
I'm going to let it simmer for a bit to see if I want to add or change anything.
Re: Raven. A homemade Atari-like computer
Posted: 13 Jul 2025 23:16
by Mikerochip
Going to build a rework list too, for the A1 boards?
Or, well. Should we create one?
If we added an "official" rework in this section or maybe the user builds section of the forum?
What made me think of it is the TT official rework schematics :P
Also, would it be easy to add in actual sockets for the 68901 etc, to the schematic?
That way we can have both the parts on the BOM, and the scocket part in the pcb.
I presume it's a chunk of extra work, for not really a lot of gain, apart from making the iBOM complete :P