Programming multiple pics with multiple programs

[Luckyborg]

I have a circuit design now which uses three Pics. Two are the same (18F4520) and one is different(12F629). My current design is all through hole parts so I have all the chips in sockets. Typically I will just program a few hundred chips with each code with a multi gang programmer then insert the chips on the boards when done. I am looking at converting to surface mount parts and my old way of programming doesn't seem to make sense.

My thought is to make a board that will connect to my product and also connect it to three melabs field programmers, each loaded with the correct software. If possible I would like to just turn them all on and have them all program at the same time. I fear that this might not work as at least two of the chips have the MCLR lines tied together and I don't know if that would cause interference or not. If I have to do each chip one at a time I guess I can. Since I am at the redesign phase I would like to do it right from the beginning, but am not sure what is commonly done. I also don't want to slow down the overall process too much

I would appreciate any advice on this idea, or any other idea which you all have had success with. If there is a commercial programmer out their for this kind of situation I would look into it. I appreciate any ideas. Tahnsk

David

[mackrackit]

All I can say is I am still a fan of removable jumpers for situations like this.

[wdmagic]

I like to use headers for programming, designed into the circuit from the beginning. you could have a set of headers and use a interface board between your programmers and regular board. You could use 1 programmer and use bus switches to determine which chip is programmed. a simple 628 chip with a button select and a couple leds could drive the bus switches.

Also if you dont want to do this and still want to use 3 programmers, then any of the pins tied togeter use a jumper, remove jumper to program.

[Luckyborg]

How were you envisioning switching between programs? As far as I can tell the field programmer only holds one program at a time. For my circumstances it isn't practical to bring our products to a PC, and I don't think I would trust my production floor to swap SD cards all the time without losing them or just inserting the wrong one at the wrong time. Do you know of any other model programmer that allows for something similar?

Luckily on my design none of the data or clock pins are tied together, so that only leaves the MCLR pins between two chips I would either have to jumper like you both mentioned or just program one at a time. I would have to think about which is more practical/economical.

Thanks for the feedback so far.

Any other ideas are also appreciated.
Thanks
David

[mackrackit]

I have not tried it yet, but Microchip will pre-program chips when ordering.

[Luckyborg]

At this point I probably should look into that, see what they charge per chip.

Thanks

[wdmagic]

you could use a mouse macro recoder to step through changing hex files and programming, there are other ways to, just depends on how much "setup" you need to do so that it gets streamlined to save time later. the fastest way to do things, if your really doing bulk, is get your program working and have microchip program the chips before they get to you. then you just have to insert and go. your going to be useing time swapping jumpers either on board or between boards, and clicking on buttons on pc to program stuff. yes you can have 3 programmers to save time from having to swap hex files but how much time are you actually going to save if you still have to stop and plug stuff in and out.

If your doing enough boards, perhaps you might want to have it setup to program say 8 boards with a chip to select each board. say a bank of programmer cords but have the chip select which one gets the power while programming, once done select new board and do it again, at the end of 8, select new chip and go through those 8, you would need to manually change the hex file after each 8, or use usb and write your own programmer software to send the hex files to the chips where it could change them for you.

Personally, it seems to me the simplest way would to be just program 1 chip over and over for however many you need then start with the next. doing one at a time or using a bank programmer (if you have money for that) or getting microchip to program them for you, would be the best and fastest solution right now.

A note on programming SMD chips, if you like to plug in a chip and program, then use on a board, I suggest using a SMD burn in module to program with, its what I use. See links below. Their awesome for programming SMD's.

3M TexTool SOIC (What I Use)

or something like this on ebay

that second one you can get with different pin configurations as well.