Granlunds FrankenSTein

[Icky]

I believe the Phoenix Sparkalaphobia is slightly larger than a normal blitter so I might need to move that PLCC socket somewhat to make sure the Phoenix blitter also fits.

@agranlund - have sent over the dimensions of the Phoenix Sparkalaphobia to help with placement.

[agranlund]

Ooh. Is it only 44 pins used on the ET4K connector/ISA slot?

Yep, only 43 unique signals from the ST side for STGA or Mega4000 type adapters!
This assumes some modifications on the ET4000 end, tying together signals that duplicate across multiple ISA pins etc.
+5V and GND will go on separate larger cables (my particular card does not need +12V or -12V)

(And looking at the VOFA schematic again it seems to only add one more signal so I should be able to implement either of these adapters on the ST side)
I already have a bunch of 44pin IDE headers so that worked out nicely

[agranlund]

I believe the Phoenix Sparkalaphobia is slightly larger than a normal blitter so I might need to move that PLCC socket somewhat to make sure the Phoenix blitter also fits.

@agranlund - have sent over the dimensions of the Phoenix Sparkalaphobia to help with placement.

Ooh, thank you! That will help for sure

[agranlund]

A couple of more evenings with Eagle left but it's getting there.

stblitter.png (615.12 KiB) Viewed 4073 times

So.. many.. traces..

[exxos]

Looking good Traces, trying routing a motherboard or 3

[agranlund]

Looking good Traces, trying routing a motherboard or 3

Haha I rather not, I have enough hatred for Eagle as it is

[agranlund]

So much free space, the possibilities are endless!

Screenshot 2020-10-26 at 22.36.32.png (898.68 KiB) Viewed 4021 times

Was originally planning on having an ethernet controller there, and the circuitry does fit in the space, but I'm more and more leaning toward having that completely separate and connected to the ACSI bus internally instead. That way I should be able to use the normal Ethernea drivers as-is.

Maybe an MP3 decoder IC from VLSI instead..

For now I think I'll just expose some more stuff to headers for easy experimentation/prototyping and order a couple of boards from JLCPCB.

[exxos]

I did look into mp3 decoder chips a while ago. But couldn't find anything which would use external ram, they were all from SD card

[agranlund]

I did look into mp3 decoder chips a while ago. But couldn't find anything which would use external ram, they were all from SD card

VLSI has a range of chips that can be feed with a bitstream from anything
And they have a data-request pin that signals when the internal FIFO has at least 32bytes free.

Something like this should be good:
http://www.vlsi.fi/en/products/vs1011.html

The software side would check the status and send it some more bytes when needed.

[exxos]

Oh cool. Would assume ST RAM wouikdnt be fast enough for it, or have enough RAM for it ? But paired with a 030 with 64MB RAM.. That would be pretty interesting