Granlunds FrankenSTein

[agranlund]

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 ;)

I don't think memory bandwidth is an issue but the size certainly would be.
An 128kbit/s MP3 is just 16KB/s (or roughly 328 bytes per frame at 50Hz)

A simple approach for a player could load the entire MP3 into memory, but ideally it would stream it in chunks from disk->ram so it could work on 512Kb machines as well.

[exxos]

A simple approach for a player could load the entire MP3 into memory, but ideally it would stream it in chunks from disk->ram so it could work on 512Kb machines as well.

Yeah that could work also :)

[agranlund]

Hahaha! My god... apparently I had the blitter socket facing down :dizzy:
Guess I have to rip up and redo the traces but I'm happy I spotted it.

Screenshot 2020-10-27 at 13.50.37.png

[agranlund]

Well that was "fun".. maybe that'll teach me to tripple check before starting to put down traces :lol:

Screenshot 2020-10-28 at 18.29.59.png

Blitter socket now on the top layer where it belongs, and the Phoenix blitter should fit.

Screenshot 2020-10-28 at 18.29.12.png

[agranlund]

Order sent, always exciting to find out how many bodge wires will be required :D

It's not a proper dev board until it has bodge wire :)
Nice work.

Ooops, forgot to route CAS0H so one was required :oops:

4mb1.JPG

But it works!! :yay2:

4mb2.JPG

After soldering the extra wires to the MMU I realised RAS1,CAS1L,CAS1R are in fact easily accessible from the top of the motherboard so I won't have to solder all four wires to the underside of the MMU socket :)
As far as I can tell I still need to grab MADR9 directly from the MMU pin though.


Found too many other little todo's for the next revision so I won't be soldering this one in place. I'll keep it sitting a little high in those ram sockets I added until I get the next rev ordered.

4mb_revb.png

[exxos]

exxos approves the bodge wire :thumbup:

[agranlund]

exxos approves the bodge wire :thumbup:

Haha I thought you might! :D

[PhilC]

Nice idea, what did it cost roughly?

[agranlund]

Nice idea, what did it cost roughly?

Thanks! I'm actually really pleased with it :)

The board was €4.72 for the five of them, plus shipping and stuff so maybe €20 or so in total or ~€4 each in such low quantities.
For the RAM I just bought an old 8MB SIMM module off ebay :lol:
It was €3.33 and it had 4 x NN5118160AJ which I desoldered, that's enough for two boards.
The pin headers, 6 caps and 3 resistors I already had lying around.

Edit: since I'm not selling anything I guess the one RAM upgrade that eventually ends up being soldered in place in my machine will have costed the total cost of all boards + ram that I bought though :lol:
That's likely going to be the next revision unless I screw that one up somehow.

[PhilC]

that's a pretty good price to upgrade your old ST