Low cost Flash Hucard

[gameofyou]

I have a small status update.  I completed the schematic design.  I just have to go through and double check everything.  I am trying to be as careful as possible, so that I can get as much correct as possible on the first revision.  Making prototype PCBs can get expensive, so I would like to make as few as possible.
 
I have also created all of the component footprints (see photo below).  Most of the parts are only used to re-program the flash memory.  If a pre-programmed flash was soldered to the board, that is the only part that would be required (& a couple capacitors).
 


And here is a closeup of the PCB outline.  Basically, all of the components have to go to the right of the green vertical line.  And they can only go on the top side.  Hopefully, there is enough room.  If not, I will have to add a notch in the PCB, and extend it longer than an original HuCard.
 

 
After doing the placement and routing the traces, then I will have to write all the software.   

[thesteve]

i recommend making a dummy card (possibly from a dead huey) to test/prototype with.
that eliminates the need to have proto cards built.
the dummy cart could just be a card with a ribbon cable attached, allowing you to breadboard the circuit under test.
also using SMD adapters for prototyping has proven quite effective

[grahf]

Excellent work so far. It would be a real shame not to fit it on a standard sized HUcard. From the looks of your component sizes though, I'm optimistic

You've got the right idea on those SMD adapters, thesteve. Breadboards are awesome.

[gameofyou]

Good news, I was able to fit all of the components onto a standard HuCard sized board.  I was also able to route the board using two layers.  J3 is not a populated part (only briefly held down to program the microcontroller) so I was able to place its footprint on the other side of the green dividing line.  Here are the photos.

All layers:

 
Top layer only:


Bottom layer only:


It is a good idea to do the prototyping work with a dead HuCard, but after reviewing the schematics I really don't see a lot of items with high risk.  Also, I need to test the pcb routing, footprints, spacings and mechanical dimensions anyway, so I think I am just going to go for it & build a pcb.

[mrhaboobi]

Very cool, way out of my league when it comes to electronics, most impressive, look forward to seeing your results

[thesteve]

im not saying not to build it
just a system test could save you a rebild

[RetroRepair]

Totally up for this when you get them done, looks really nice! 

[henrycsc]

Yep, I'm game for one of these too.  Hucard forever!

Still amazed by what all of you guys continue to come up with!

[grahf]

Looks like you did a nice job on the routing. I'm really looking forward to this. It just might get me to finally fooling around with some PCE programming.

[Chuplayer]

Freakin' sweet, man.

[gameofyou]

A small update: 
I have been working on both the firmware (that executes on the circuit board) and the PC software (which will be used for downloading the games).  They are both coming along pretty well.
 
I will get my prototype pcbs on Monday (supposedly).  They are very low-cost protos (no solder mask or silkscreen or beveled edge).  I will try to upload a picture Monday if I get time.  Once I get the protos working, I will order some full-spec pcbs.
 
One challenge will be assembling these boards.  The parts were only available in surface mount packages and the pitch of the pins is quite small (0.5mm), on some of the parts.  I will have to crank up my soldering skills a notch for this board.  lol.
 
One other thing I am debating is whether to get gold flashing on the connector pins.  It looks like it may add significant cost to the pcbs to do this ($5 or more).  From what I know now, I believe that I could set the price for the assembled boards at $40 (plus shipping), without the gold flashing.  That's not too far from my original goal of $35.

One last thing is that when the time comes, I may want one of you to be a test user for this flash HuCard.  Preferably someone with a Turbografx-16 (since I have only a PC-Engine).  If anyone would be interested in this, just shoot me an email (from my GamingEnterprisesInc site).  I'm probably still a month or so away from being at that stage, though.

[burn_654]

Glad to hear that things are going smoothly

I have a PC-Engine Duo, but I've installed the region switch mod. I don't know if that's helpful to you or not...
Regardless, looking forward to ordering one of these bad boys when they're available.

[grahf]

Sounds great. I'd love to be a tester, but I don't have a TG16. There are a few guys on this forum with electronics knowledge AND a TG16 (BlueBMW? thesteve?), so they'd be better suited to help you test.

Personally, I'd say the gold plating is worth the $5. These boards will probably see a lot more insertion/removal than your average HuCard, so longevity on the contacts is definitely worth it. Of course cheaper is better, but I think the price is probably already cheaper than what some people were expecting. Just my opinion.

Looking forward to more updates! Really excited about this.

[soop]

Sounds great. I'd love to be a tester, but I don't have a TG16. There are a few guys on this forum with electronics knowledge AND a TG16 (BlueBMW? thesteve?), so they'd be better suited to help you test.

Hear hear.  Plus, if something IS wrong, they'll have more insight into what the problem is rather than "it doesn't work "

[thesteve]

id love to test a proto board.
id even test it on several systems