TheBackShed.com

Forum Index : Microcontroller and PC projects : Pin25 Help

Page 2 of 2

Author

Message

WhiteWizzard
Guru

Joined: 05/04/2013
Location: United Kingdom
Posts: 2934

Posted: 10:41pm 15 May 2015

Copy link to clipboard

Print this post

John/Rob,

Do you know what silicon version you were using?
When I load firmware onto a PIC using MPLab IPE and a PicKit3, after 'Connect'ing the correctly selected Part and Programmer the version is displayed in the 'message' window (sorry I have to describe it like this but I am not in front of my Laptop to be able to grab a screen shot - hopefully you can relate to what I am describing).

I have seen versions something like 'A0000001' and 'A000002' (probably not the correct number of zeros - but the point is there is a '1' or a '2').

If you can confirm your version(s) this occurred on then maybe worth trying the other version (if you haven't got both already).

It appears that the most resent chips I have bought are all version '2' which you would like to think has fixed any known issues with silicon release '1'.

This is a 'stab in the dark' but like you mention - it could be a silicon issue.

WW

Geoffg

Guru

Joined: 06/06/2011
Location: Australia
Posts: 3285

Posted: 05:23am 16 May 2015

Copy link to clipboard

Print this post

This does not sound like a compiler/library issue but simply a case of "ground bounce" as the capacitor discharged. The energy stored in the cap has to go somewhere and I bet that is the cause.

Geoff

Geoff Graham - http://geoffg.net

jman

Guru

Joined: 12/06/2011
Location: New Zealand
Posts: 711

Posted: 12:25pm 16 May 2015

Copy link to clipboard

Print this post

If I use the above circuit from the manual and use the internal pullup
Every pin EXCEPT pin 25 works. The issue remains ONLY on pin 25

So why would the debounce cap only effect pin 25

The other odd thing I tried the other way ie cap to vcc and pulldown
and it works with no resets (Now I am going grey ah wait a minute I am grey already)

This a look at the waveform when pressing the button all the pins display
pretty much the same if not identical

@ WhiteWizzard
The MX170's display following in the IPE
2015-05-17T10:07:09+1200- Completed loading IPE.

*****************************************************

Connecting to MPLAB PICkit 3...
Firmware Suite Version.....01.34.11
Firmware type..............PIC32MX

Target detected
Device ID Revision = A2

The MX150 dispalys the following
2015-05-17T10:07:09+1200- Completed loading IPE.

*****************************************************

Connecting to MPLAB PICkit 3...
Firmware Suite Version.....01.34.11
Firmware type..............PIC32MX

Target detected
Device ID Revision = A1

Regards
Jman

bigmik

Guru

Joined: 20/06/2011
Location: Australia
Posts: 2949

Posted: 01:24pm 16 May 2015

Copy link to clipboard

Print this post

Hi Jman, All,

Firstly John, my apologies for not doing the test the other day when I promised I would try to duplicate your setup as closely as I could..

Secondly, I have finally `extracted my digit' and duplicated as you suggested.

Cap mounted close to the PIC, Resistor mounted on the switch and 3 wires about 6" (150mm) long to the switch.

Thirdly I can confirm the reset issue but it is nowhere as bad as you are experiencing.. See the below screen capture

That is running this code

SetPin 25,din
mik:
Print Pin(25);
Pause 250
GoTo mik

The first Reset occurred after approximately 59secs (each line is 10seconds long).

That was about 1second between presses.. the next couple of times I went madly and random speeds pressing the button and it occurred after 18 and then 8 seconds.

So ultimately it is CONFIRMED ... but I cannot get the 95% resets you are experiencing.. mine is more like 5% resets but still that could be enough to upset your program if it was released into the wild.

Regards,

Mick

Edited by bigmik 2015-05-17

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

jman

Guru

Joined: 12/06/2011
Location: New Zealand
Posts: 711

Posted: 01:36pm 16 May 2015

Copy link to clipboard

Print this post

Thanks Mick

At least I am not going mad :)

JG

bigmik

Guru

Joined: 20/06/2011
Location: Australia
Posts: 2949

Posted: 01:44pm 16 May 2015

Copy link to clipboard

Print this post

jman said
At least I am not going mad :)

John,

There is NO Guarantee on that statement.. If I agree with you then we might BOTH be mad..

I suspect power supply differences might be the difference between your setup and mine (I am plugged into a USB3 (1.5A capable port) and using MuP with its own 3v3 Regulator.. I believe from Jim's message you may be using the 3v3 from the CP2102 board??? That would probably peak around the 60mA capacity..

In either case the issue is there and probably due to the silicon of the chip.. I suspect a swing below 0V maybe a 1N5817 or 1N5819 clamping diode might work to draw away the negative voltages if that is the cause.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

Page 2 of 2

Print this page

To reply to this topic, you need to log in.