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BobEdge
- 1st July 2015, 16:20
Hi All,

I have a project where there are 3 818's on the same PCB, and with the same software.
Has anyone tried programming multiple devices, at the same time using a Pickit 3?

Regards
Bob.
mark_s
- 1st July 2015, 19:14
Doing a quick Google search, I found..

http://www.microchip.com/forums/m485958.aspx


Add: For a small fee Microchip will program your chips at the factory.
Heckler
- 1st July 2015, 20:52
If I cared about reliability or I had to travel a great distance to fix an issue or it was a commercial product... I would not attempt it.

For hobbyist stuff... give it a go!! :D
Dave
- 1st July 2015, 23:08
I would be somewhat leary of trying to program 3 devices at the same time as there is a handshake process that has to take place during the flash process. If the timing of 1 of the devices is a bit different there could be a conflict. I am assuming you are talking about connecting the PGC, PGD, and RST line's together?
Also there may be a problem with Loading.
towlerg
- 2nd July 2015, 00:14
@Dave, I'm not sure you are correct re. handshaking. Don't know about LVP but for standard high-voltage programming all I see is clock and data and VIHH on MCLR. Of course you wouldn't be able to verify so I guess you could only use this for novelty items. But if you really had to do this you have the PIC device verify its code space against a checksum.

George
BobEdge
- 2nd July 2015, 11:57
Thank you all for the replies.
This is an industrial product, so not worth taking the risk.
I admit I had not thought about the verify part of programming.

Regards
Bob.
peterdeco1
- 2nd July 2015, 17:38
Hi Bob. I mentioned this in another post a while back. I have programmed 10 PICs at once for use in commercial products BUT the products were tested before releasing them. Simply stack one PIC on top of each other so that all the pins are in parallel and all will program. If you stack say 6 and the 4th one up isn't connected then the chain is broken and 4,5 and 6 won't be programmed. Try it, it works.
Ioannis
- 3rd July 2015, 09:33
Keep in mind that Pickit is not for production as Microchip states and as I have confirmed.

From times to times I had chips that were not programmed 100% correctly.

With other programmers like ICD3 or Elnec Pikprog+ never had a problem of corrupt code.

Ioannis
ardhuru
- 3rd July 2015, 16:20
Simply stack one PIC on top of each other so that all the pins are in parallel and all will program. If you stack say 6 and the 4th one up isn't connected then the chain is broken and 4,5 and 6 won't be programmed.

I second this; never had a problem. Been cascading chips like this since the good old 27XX EPROM days.