PICKit3 programmer question.

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rob...@hotmail.com

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Oct 18, 2022, 1:25:36 PM10/18/22
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Hi all,

I have a question about a PICKit3 programmer. Instead of trying it out and blowing up my programmer I thought I ask you.

I often have a device that operates at 3.3. Volt and the PIC running at 5 Volt. I use level shifters to get then connected. I program my PIC in-circuit so I do not remove it from the breadboard.

I can run the PIC at 3.3. Volt so that I do no longer need any level shifters.

My question is the following. Can I reprogram my PIC in-circuit when it is running at 3.3 Volt or will I kill the PIC?

Are there any issues I should take into account, e.g. only use Low Voltage Programming or 'do not try this at all!'?

Thanks.

Kind regards,

Rob

Evan Venn

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Oct 18, 2022, 1:51:35 PM10/18/22
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Post here or send me direct your circuit.  I will get my CTO to review and 'pass judgement'.  He is one of the world experts on this subject and he knows the pk2/3/4 inside out.


Evan 

From: jal...@googlegroups.com <jal...@googlegroups.com> on behalf of rob...@hotmail.com <rob...@hotmail.com>
Sent: Tuesday, October 18, 2022 6:25:35 PM
To: jallib <jal...@googlegroups.com>
Subject: [jallib] PICKit3 programmer question.
 
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Matthew Schinkel

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Oct 18, 2022, 11:15:46 PM10/18/22
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I use PICKit3 ICSP with a 3.3v circuit. I haven't had any problems.

Matt.

vsurducan

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Oct 19, 2022, 12:07:34 AM10/19/22
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Pickit2/Pickit2+ (Evan's firmware/software) works ok as you described. I guess will be no issue on Pickit3 either.
best wishes,

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Rob CJ

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Oct 19, 2022, 1:45:42 PM10/19/22
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Hello all,

Thanks for your answers so it is save to run the PIC (and the rest) on 3.3 Volt and program the PIC in-circuit with my PICkit3.

I will give it a try since it saves me a lot of level shift connections and wires on the breadboard.

Thanks again.

Kind regards,

Rob

Van: jal...@googlegroups.com <jal...@googlegroups.com> namens vsurducan <vsur...@gmail.com>
Verzonden: woensdag 19 oktober 2022 06:07
Aan: jal...@googlegroups.com <jal...@googlegroups.com>
Onderwerp: Re: [jallib] Re: PICKit3 programmer question.
 

Mike

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Oct 19, 2022, 4:40:21 PM10/19/22
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It should be noted that the PICKits also program "LF" devices.  So, programming at 3.3V should not be a problem.  Do brownout settings have to be changed?

Regards,
Mike

Evan Venn

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Oct 19, 2022, 4:45:34 PM10/19/22
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I know how the software works.

The formal position is. Do not connect a pk3 or pk2 to the circuit and then star the Windows application with AutoDectect checked.

Why?  The software will control the PK3 or Pk2 with respect to 3v3 for a specific chip.  But, if AutoDectect is checked and the previous chip is use is a non 3v3 chip then the Pk3 ot Pk2 will apply 5v0 during the detection process.

So, best practice.  Use manual selection of the chip and do not use Auto Detect when using a 3v3 circuit. 
From: 'Mike' via jallib <jal...@googlegroups.com>
Sent: Wednesday, October 19, 2022 9:40:21 PM
To: jallib <jal...@googlegroups.com>
Subject: Re: [jallib] Re: PICKit3 programmer question.
 

vsurducan

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Oct 20, 2022, 2:27:39 AM10/20/22
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Evan, I would say: do not boot your PC with Pickit2 connected to the USB. Why? because there are chances to end with corrupted firmware. It happened once. Fortunately having an old programmer and the firmware may solve this possible issue.
Pickit2 seems better than pickit3. Pickit4 is better than any previous ( maybe because it's Atmel based ? :P ) but its software stinks^3.

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evan....@googlemail.com

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Oct 20, 2022, 3:09:42 AM10/20/22
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Sorry. Change 'boot' to 'start the application with the programmer attached to the chip/circuit'.

 

  1. Yes. You cam, easily, end up with corrupted firmware as the PK2 or pk3 searches through the chip families. I can tell you the exact circumstances – it essentially changing from the chip families with MSB to non MSB chip family and you use Automatic Search OR Tools/Communication AND NOT manual chip selection    This rule is ONLY applicable to the released versions of the PK+ database. PK- changed the database and made the situation a lot worse where you can whack a chip with ease.
  2. Old programmer and old firmware does not resolve. 
  3. PK+CommandLine and PK4 resolve this.  It makes you select the chip.  You take the responsibility for chip selection and PK4 even warns you of the danger.
  4. Pk2 is better that PK3.  PK4 is different from PK2 and PK3 and the PK4 is not the best.  We are working to gain access to the PK4 protocols to write our software for the PK4.

 

Hope this helps.

 

From: jal...@googlegroups.com <jal...@googlegroups.com> on behalf of vsurducan <vsur...@gmail.com>
Sent: Thursday, October 20, 2022 7:27:27 AM
To: jal...@googlegroups.com <jal...@googlegroups.com>
Subject: Re: [jallib] Re: PICKit3 programmer question.

 

Evan, I would say: do not boot your PC with Pickit2 connected to the USB. Why? because there are chances to end with corrupted firmware. It happened once. Fortunately having an old programmer and the firmware may solve this possible issue.

Pickit2 seems better than pickit3. Pickit4 is better than any previous ( maybe because it's Atmel based ? :P ) but its software stinks^3.

On Wed, Oct 19, 2022 at 11:45 PM 'Evan Venn' via jallib <jal...@googlegroups.com> wrote:

I know how the software works.

 

The formal position is. Do not connect a pk3 or pk2 to the circuit and then star the Windows application with AutoDectect checked.

 

Why?  The software will control the PK3 or Pk2 with respect to 3v3 for a specific chip.  But, if AutoDectect is checked and the previous chip is use is a non 3v3 chip then the Pk3 ot Pk2 will apply 5v0 during the detection process.

 

So, best practice.  Use manual selection of the chip and do not use Auto Detect when using a 3v3 circuit. 

 

Evan

 

From: 'Mike' via jallib <jal...@googlegroups.com>
Sent: Wednesday, October 19, 2022 9:40:21 PM
To: jallib <jal...@googlegroups.com>
Subject: Re: [jallib] Re: PICKit3 programmer question.

 

It should be noted that the PICKits also program "LF" devices.  So, programming at 3.3V should not be a problem.  Do brownout settings have to be changed?

 

Regards,

Mike

 

 

On Wednesday, October 19, 2022 at 1:45:42 PM UTC-4 rob...@hotmail.com wrote:

Hello all,

 

Thanks for your answers so it is save to run the PIC (and the rest) on 3.3 Volt and program the PIC in-circuit with my PICkit3.

 

I will give it a try since it saves me a lot of level shift connections and wires on the breadboard.

 

Thanks again.

 

Kind regards,


Rob

 

vsurducan

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Oct 20, 2022, 10:20:13 AM10/20/22
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Ok, I'm reformulating: Pk4 is faster than any old Pk programmer.  But I had problems with Pk4 too which suddenly died. It was in warranty period so the Irish guys replaced it quite fast... The only issue was the shipping costs for returning the programmer which was almost equal with a new programmer...

About writing software for the pk4, each person has the free will in choosing his/her own suffering. :)


evan....@googlemail.com

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Oct 20, 2022, 10:37:43 AM10/20/22
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The PK4 software will not be the same architecture as Microchips.  It will be developed from new. :-(

vasi vasi

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Oct 20, 2022, 11:27:10 AM10/20/22
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So, that is why my 18f2550 transformed into an USB2Serial device stopped working... maybe is not burned...

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Rob CJ

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Oct 20, 2022, 12:48:17 PM10/20/22
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Hi Evan,

Thanks for the hint. I will keep that in mind.

Kind regards,

Rob

Van: 'Evan Venn' via jallib <jal...@googlegroups.com>
Verzonden: woensdag 19 oktober 2022 22:45
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