Interest check: An updated MiniITX-MiniMig ( Pics!!! )

[Illuwatar]

I did the test You wanted me to do. By hardwire vsync to VCC (5V) of the AD724, I got a stable picture. But instead, all colors went wrong (black background with hardly noticeable contours of the floppy hand) and the pictures are skewed. Restoring vsync to be controlled by the FPGA, I got back the smooth vertical scroll, otherwise a clear and sharp (as sharp it can be at composite) picture with correct colors.

yaqube wrote:
Ok, I had a look at my sources and found that in not scan doubled mode Dennis' core outputs a static one on vsync output and my core outputs vsync signal. Both cores outputs csync on hsync output. The AD724's vsync and hsync inputs are XNOR'ed so in this case it may lead to missing vsync (is the screen slowly scrolling verticaly?)

If you have connected the AD724's vsync input to the FPGA's vsync output with a resistor please remove it and apply  high logic level to the vsync input of the AD724. Please tell me if it works so I will make a modified version.

To all that have mailed and PM'ed me regarding buying boards: You have not been forgotten. I just don't want to give out any unclear information and I must be sure that the board works to 100%. I have to put together a complete BOM with Digikey numbers and prices to be able to get a cost figure for the parts. The board layout must be corrected and finally, the total numbers of boards have to be counted for order. For those who wants complete, working boards, be aware that I have to put them together by hand, one by one.

[yaqube]

@Peter

I have checked the sync signals with my scope and cannot see anything wrong. :-(

I have also found an AD724 in my drawer :-D so I will make a small test board during the weekend and see why it doesn't work as expected.

[FrenchShark]

Illuwatar wrote:
I did the test You wanted me to do. By hardwire vsync to VCC (5V) of the AD724, I got a stable picture. But instead, all colors went wrong (black background with hardly noticeable contours of the floppy hand) and the pictures are skewed. Restoring vsync to be controlled by the FPGA, I got back the smooth vertical scroll, otherwise a clear and sharp (as sharp it can be at composite) picture with correct colors.

Did you try hardwiring vsync to GND ?
What you are describing looks like hsync (=csync) being reversed because vsync = 1, if vsync is set to 0 the inversion should disappear.

Regards,

Frederic

[yaqube]

The csync signal has the same polarity as in the original core. But I have changed blanking to match what can be seen on a real Amiga (left overscan was invisible).
On regular VGA monitor it works ok but the encoder chip can sample incorrect black level during hsync periods if they are not blanked entirely (it could explain the very dark background). I will check it and fix it.

[Illuwatar]

I re-ran the test with the vsync connected to logic high, and this time I got a stable picture with correct colors. The previous try was failed due to a bad connection (the vsync pin of the AD724 was floating - these tiny connections are hard to see). I haven't tested overscan, only with the boot picture, but You certainly will fix this. I'm waiting for an updated core to test - when it runs fine at my board, I will declare it completed regarding electronic functions.

I did the Mini-ITX verification too today - the hole pattern of the PCB matches perfect a Epia-board and the case it was installed in. The verification left to do is to test the headers for the serial port and the joystick ports. When that passes, I will finalize the design in Protel (some cosmetic changes) and start counting the mails/PM's. A BOM must be assembled and a new project to be created at my homepage.

[skipp604]

Apologies for the silly question, but what's a 'BOM'? :-)

[yaqube]

http://en.wikipedia.org/wiki/Bill_of_materials

[skipp604]

All clear now :-) Thanxx

[cv643d]

Illuwatar, do you work at Telefonplan? I think I saw someone looking like you there  :-)

Nice work btw...

[Illuwatar]

Yes - I'm working at Telefonplan. Nice that not every Amiga freak is on the other side of the Sea... :-)

[Illuwatar]

My home page is updated now. The new MiniMig got its own project page (not to mix it up with the old MiniMig). Schematics and some pictures are there and more will come as work is progressing.

[Illuwatar]

Hi again - You are not forgotten!

I have been working on the production part of this thing and can present BOM and Protel drawings at my homepage. I have managed to find Digikey part numbers for almost all parts needed. And I have an estimated cost for the thing in materials: €160 for the components and €18 for the bare PCB. These prices does _not_ include any profit, shipment, VAT or assembly and they are estimated.

But I have also ended up in a rather big problem that could (would) delay the project: The SD-card holder aren't made anymore. It seems like Alps has phased it out of their product line. And there aren't any pin-compatible replacement part. This means that I have to do a partly re-design of the PCB for both the Mini-ITX and Mini versions.

Edit: The SD-holder model number is ALPS SCDA1A0900

[Illuwatar]

The PCB is now updated with a newer ALPS SD/MMC card holder. The SCDA3A0102 type became the replacement. Still, the Mini MiniITX has to be done.

I have also been reading through all PM's and mails and assembled an "interest" list that looks like this:

skipp604
Firedawg
trip6
chiark
amigadave
IOWASURFER
pyrre
jimbo100
rja4096

Some wants two boards, some wants assembled and tested boards and some just want one. Totally estimated is about 15 PCB's wanted. The prices for the PCB shown in the entry above (€18) is calculated on a 20 board run. The part price is for a single board, single order (€160). Larger buys will make it cheaper. If someone has contacts with China for direct buy, it will be much cheaper...

[Darrin]

Have you asked aCube if they would like to do a run based on your design?  They might have the contacts and the ability to do a production run in the quantities required to lower the cost significantly.

[skipp604]

Great news, Peter!

I am still absolutely interested, just can't wait for my board!

Hope all goes smooth from now on. Thanks for keeping us updated.


Keep up the good work.

[trip6]

Excellent work... I still say the missing piece is designing a metal backplane cutout so that any standard Mini-ITX form factor case can be used, and then figuring out how to mass produce the backplane cutout... But the board is coming along wonderfully....