amiga-news.de - The AGA-A3000: Amiga fans equip boards of the Commodore prototype AA3000

14.Aug.2018
Radiosity (IRC)

The AGA-A3000: Amiga fans equip boards of the Commodore prototype AA3000
The AA3000 and A3000+ have been further developments of the Amiga-3000 mainboard which for the first time should use the new AGA chipset. Additional to the AGA chipset, the revised board should contain a digital signal processor which was supposed to be used for 16-Bit audio and floating point operations. Altogether only few prototypes were produced before the project was abandoned in favour of the A4000.

In spring 2018 Matthias 'Matze' Heinrichs succeeded in getting five blank AA3000 boards. The boards looked pretty fine and the schematics were included as well. The source codes for the PALs can be found in the Dave Haynie archives - so the idea was born to equip the boards of their own. Both Heinrichs and Christian 'Scrat' Euler have succesfully equipped a board and thus have a working AA3000.

Euler - who points out that Heinrichs did the "pioneer work" and thus made his own project possible - has documented his work and took several pictures. He wrote:

"... so we invested time und used the soldering iron. Matze completed his board a little bit earlier therefore he could give me some hints. It took about two months for assembling and launching my board (including longer breaks), I had to reorder components three times and to steal the delayline of one of my two A3000 boards.

Unfortunately the DSP cannot be bought at reasonable prices any longer so we had to improvise. The Commodore guys used a different RTC component for this board which via I2C bus is connected to the DMAC chip. This feature is not available in any of the DMAC revisions so Matze made an adapter board for a common RTC.
Some pictures of the assembly...

The (almost) blank board:

...which is getting equipped...

The CPU I took from an old Apple Powerbook (which was a victim of the gravitation and beyond remedy...)

Soldering THT a lot is not that fun...

It is actually an AA3000!

Almost completed!

Testing...

Is it really working?

As I launched it for the first time nothing happened. After a lot of measuring it turned out that the CPU was active for a short time and then sank into a "long sleep". Clocks were active, the chipset produced SYNCs... then I recognised that an IC in the clock section was not properly equipped - instead of a F type, a LS type was installed.

I did exchange the IC, afterwards the CPU worked fine. Then I found out that the EPROMs with the Chucky-DiagROM were broken. New ROMs installed and then at least the Power-LED started flashing. Okay, the CPU lives!

But the screen kept dark...what else could be wrong? Eventually it turned out that the pins on the DAC did not properly got the tin...soldered again, first attempt:

Second attempt: Tadaaaa!

Kickstart-ROMs installed, switched on, worked. Party!

Now CS Mk2 installed, Picasso IV installed, Deneb installed...worked! Starstruck had to be.

What's next...?

Currently the experimental setup is still standing on the table. Some components of the board are still missing...the parallel port and the SCSI port as well. I also have to build the RTC adapter. Afterwards the board will be tested in detail and then integrated into my main A3000. Matze is going to build a new busboard. Currently the daughterboard of the A3000 is used (the one from the A4000 does not fit). Therefore the video output only has 12 Bit RGB. So the AGA looks a little bit strange via the PIV-FliFi."

Downloads:

Schematics: AA3000_Rev2_Schematics.pdf
System specifications: AA3000_System_Specs.pdf (cg) (Translation: dr)

[News message: 14. Aug. 2018, 01:25] [Comments: 0]
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