Possible new free MiniMig PCBs already exits

[aperez]

I happened to be in my local electronics junk shop today, and came across (and ultimately purchased) 111 pristine, unused PCBs which were designed to be used as FPGA demo boards. They have one 240-pin QFP landing area , as well as two TSOP pad sets for SDRAM and/or SRAM.

The boards were $1/each, and I wound up getting them at half-price, since I successfully argued that there was no way for the seller to know that they didn't contain design errors, and were thus potentially unusable.

Anyways, I'd like to offer these boards free of charge (I ask only that any interested parties pay actual shipping) to anyone who wants to work with me (or on their own) on a board bring-up process for these. They need not be minimig-related, although I would prefer to get it to that point.

I've done some research into which 240-pin FPGA's will fit with this board design, and there are both Cyclone II and III FPGA's in the 240-pin QFP form factor, the cheapest of which, the EP3C16Q240C8 costs under $30 in single quantities.

Another option would be the 5V-tolerant Altera EPF6016QC240, which is from the FLEX 6000 family and has 16K gates. They can be had from Digi-Key for $42

[kipper2k]

I'd be interested in a board or 2, i'm not too up on the minimig, but my soldering skills are good so i would be willing to give it a try.

[aperez]

Originally Posted by kipper2k

I'd be interested in a board or 2, i'm not too up on the minimig, but my soldering skills are good so i would be willing to give it a try.

PM Me your postal mail info and I'll send a couple your way. These are nice, high quality PCBs.

[Shadowfire]

You have a *lot* of work ahead of you.

U8 and U7 are obviously 3 terminal voltage regulators. Ring out which pin #'s they feed on the TQFP. Also, Y2 and Y3 output should also be rung out. If you can find a match on clock and VCCcore/VCCIO pins in a datasheet, then you most likely know which FPGA it was intended for. It looks to be one of the external-serial-flash-programmed variety.

Second, you have no video or audio output capability on this board. Both are analog outputs, and you would need to spin a daughter board to plug into one of the headers to supply this (likely, you will also need stuff like voltage level shifters for interfacing other hardware.) This will run you a bunch of money.

You need to ring out each pin# from the FPGA to the pin# on each IC position on the board, then determine WHAT IC's are supposed to go there.

Then, you have the unenviable task of porting Minimig to the new board, almost certainly requiring a new RAM controller (assuming the new IC's are even big enough to make a Minimig possible), and video/audio output section. You don't appear to have a microcontroller to control bootup, so you'd need a clever workaround for that.

All in all, I'd definitely rather pay $300 for a minimig than sink 300+ hours into what you are proposing. Unless, of course, you're doing it for fun.

[aperez]

Originally Posted by Shadowfire

You have a *lot* of work ahead of you.

I'm well aware.

Originally Posted by Shadowfire

U8 and U7 are obviously 3 terminal voltage regulators. Ring out which pin #'s they feed on the TQFP. Also, Y2 and Y3 output should also be rung out. If you can find a match on clock and VCCcore/VCCIO pins in a datasheet, then you most likely know which FPGA it was intended for. It looks to be one of the external-serial-flash-programmed variety.

Yep, that's the plan, and I'm already progressing on that front. There are a limited number of 240-pin FPGA's on the market (and previously on the market)

Originally Posted by Shadowfire

Second, you have no video or audio output capability on this board. Both are analog outputs, and you would need to spin a daughter board to plug into one of the headers to supply this (likely, you will also need stuff like voltage level shifters for interfacing other hardware.) This will run you a bunch of money.

The daughtercard solution is of course the one I came up with as well. As for the cost, I see no reason why the cost has to be "bunches". These daughterboards can be hand-made until I'm comfortable with the output quality., then sent off to manufacture

Originally Posted by Shadowfire

You need to ring out each pin# from the FPGA to the pin# on each IC position on the board, then determine WHAT IC's are supposed to go there.

As stated above, this is already well underway.

Originally Posted by Shadowfire

Then, you have the unenviable task of porting Minimig to the new board, almost certainly requiring a new RAM controller (assuming the new IC's are even big enough to make a Minimig possible), and video/audio output section. You don't appear to have a microcontroller to control bootup, so you'd need a clever workaround for that.

I believe U5 may have been the intended microcontroller. Either way, there's no reason why the microcontroller can't live on the aforementioned daughterboard. U5 may also have been a video output IC, given it's proximity and relation to J3. I'm pretty sure J1 is the in-system-programming header.

Originally Posted by Shadowfire

All in all, I'd definitely rather pay $300 for a minimig than sink 300+ hours into what you are proposing. Unless, of course, you're doing it for fun.

I most definitely am. I already own an Altera DE2 development board.

[alexh]

Unless you have the schematics for the PCB's then they are just scrap.

[aperez]

Originally Posted by alexh

Unless you have the schematics for the PCB's then they are just scrap.

Believe what you want. I can pin out the PCB. Nothing to see here folks, besides a lack of imagination and fortitude.

[Photon]

As for second-guessing... well, you're bound to get that on any forum I think. Seems you have a plan, so I say go ahead and at least I will be interested in progress We have quite a few people here capable of building electronics and designing PCBs who could offer friendly advice (should you need it). I hasten to add I'm not one of them - it would take too much time from my other projects, just wanted to say hello and welcome.

[prowler]

^ What Photon says.

[Hewitson]

Personally I don't think itd be too difficult to make use of these boards.

I'm not willing to do any video circuit design, but the audio would be a piece of cake.

I'll wait and see how others progress before I put my name down for a couple. The AVR's are giving me enough grief at the moment!

Very nice of you to think of us here while you were at the shop. Cheers.

[Jope]

These are cheap if your time is worthless.. Small runs of PCBs aren't THAT expensive in 2010. I'm with AlexH on this.

[Hewitson]

Anyone with a multimeter and half a brain could make use of that board. Buzzing out a few signals is going to take a fraction of the time of designing a whole new PCB and getting it manufactured. Not to mention a fraction of the cost.

Im not saying I think its suitable for Minimig projects, I don't. I do however think itd be great for someone wanting to start off with FPGA's.

[alexh]

Originally Posted by aperez

I can pin out the PCB.

Originally Posted by Hewitson

Anyone with a multimeter and half a brain could make use of that board. Buzzing out a few signals is going to take a fraction of the time of designing a whole new PCB and getting it manufactured.

The Silk Screen on the PCB doesn't even have the part numbers or the values for all the capacitors & resistors. Even with the reference design for the two identified FPGA's from Altera it is going to be a long arduous task unless they are very similar. If you are very lucky this might be a student / graduate developed PCB which is a 1:1 copy of an Altera reference design.

I've done some research into which 240-pin FPGA's will fit with this board design, and there are both Cyclone II and III FPGA's in the 240-pin QFP form factor, the cheapest of which, the EP3C16Q240C8 costs under $30 in single quantities.

How did you research which 240-pin FPGA's would fit the board? You googled for all 240-pin QFP FPGA's with those dimensions and these were the only two that came up? You made an educated guess by tracing the crystal or JTAG back to the FPGA and working out the pin number and cross referenced this with pinouts in the data sheets for various devices?

Originally Posted by aperez

Nothing to see here folks, besides a lack of imagination and fortitude.

More a sense of realism and experience. Part of my job is to reverse engineer competitors PCB's and determine pinouts without schematics. It is much easier with a populated board but even then. Good luck.

[seuden]

I'm sure alexh as well as I wish you the best of luck tho