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Maniccyberdog Newbie Joined: 19/02/2018 Location: United KingdomPosts: 13
Posted: 07:01am 19 Feb 2018
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Hi all,
I’m new to the world of PIC32s, I have managed to solder on the PIC32 to the MaxiMite PCB and have got my self an Ebay PIC3kit, can anyone tell me the minimum components that are required on the PCB to program the firmware?
OA47 Guru Joined: 11/04/2012 Location: AustraliaPosts: 1013
Posted: 07:42am 19 Feb 2018
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If you refer to Geoffs manual, the minimum external components are the Vcap (10uF XR5 or 47UF/16V Tantalum ) and a 10K resistor from pin 1 to Vcc plus the rest of the Vcc and Gnd connections. Without any external circuitry you can set the PICKIT3 to supply Vcc(3V3) to the chip.
Hope this helps.
IanT Senior Member Joined: 29/11/2016 Location: United KingdomPosts: 115
Posted: 09:51am 19 Feb 2018
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Should that be a 6v 47uF Tantalum?
IanT
WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2959
Posted: 10:27am 19 Feb 2018
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Any Tant or Ceramic between 10uF and 47uF should work just fine. Voltage at least 6v - again, any higher is fine. With a Tant, then ensure you get it the correct way round as they are polarised!
Only word of caution is not to use an Electrolytic for vCap.
Good luck; and do let us know if you get it going . . . .
Edited by WhiteWizzard 2018-02-20
Maniccyberdog Newbie Joined: 19/02/2018 Location: United KingdomPosts: 13
Posted: 06:46pm 19 Feb 2018
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Thanks for the advice, off to do some shopping. I’ll post my results soon
OA47 Guru Joined: 11/04/2012 Location: AustraliaPosts: 1013
Posted: 10:02am 20 Feb 2018
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I seem to remember Geoff saying that the higher voltage tants had better Equivalent Series Resistance (ESR) values so he recomended the 16v variety. OA47
flip Senior Member Joined: 18/07/2016 Location: AustraliaPosts: 117
Posted: 11:58am 20 Feb 2018
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I had an idea that aluminium electrolytic caps need a forming voltage, so if voltage is too low, the capacity is reduced(i.e. you need bigger values). Don't think it applies to Tant's as much/if at all.
Not recommending it but I run 2 uMite backpacks both with a 3V 100uF tantalum on the Vcap pin and they both still work perfectly after 100-200 on/off cycles over past few years(remember Vcap is 1.8V). I repeat I'm not recommending this but it should give comfort about how un-fussy the device is
Regards PhilEdited by flip 2018-02-21
Maniccyberdog Newbie Joined: 19/02/2018 Location: United KingdomPosts: 13
Posted: 08:00pm 20 Feb 2018
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Wow Farnell are quick, ordered at 8:00pm got next day. I have programmed the PIC32, but needed to add 3.3v regular and a few caps so that I could power from the USB socket. My Ebay PICKit3 doesn’t seem to power the circuit. Ready to add the extra components soon, to finish my MaxiMite!
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 2006
Posted: 08:54pm 20 Feb 2018
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To get the PicKit to power the circuit you have to go into 'Advanced mode' and click on power then tick the box to power from the PicKit. Paul."It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
Maniccyberdog Newbie Joined: 19/02/2018 Location: United KingdomPosts: 13
Posted: 06:50am 21 Feb 2018
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I wish that was the answer, but I already tried that. I did wonder if one of the through holes on the power rails was breaking the circuit. Adding all’s the caps would have fixed this.
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2171
Posted: 07:45am 21 Feb 2018
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Heads-up powering the device from the PICKit:
1 It is weedy current so PIC only. i.e. don't power from the PICKit and program in-circuit if the power rail goes off to other parts of your board - you you will be trying to power your board from the PICKit also and although it is unlikely to hurt it, it'll have you scratching your head wondering why it won't talk to the PIC.
2 It has trouble getting to the supply voltage - so instead of asking for 3.3, select the next one down or so. I have to program 5V PICs at 4.75V otherwise MPLAB always complains it couldn't find the device - even in the adapter with nothing else attached.
Other than these two caveats, I find the PICKit excellent - the latest MPLAB software not so much but hey, it works.Edited by CaptainBoing 2018-02-22
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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I did wonder if one of the through holes on the power rails was breaking the circuit. Adding all’s the caps would have fixed this. 
