ICD2 USB clone - how to get it to work with 3.3V PIC24s ???

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szlovak

Joined: 24 Jan 2005
Posts: 22

06 Jul 2006 0:51 pic vdd low icd2

polymath wrote:

szlovak

If you read thread and understood, you would know that ICD2 monitors target Vdd and modifies +VHH according to the PIC selected, this being transparent to the user.

However, you have given me an idea! - thank you.

I understand whole thread. 5V on MCLR will fry this chip and Mplab does not say a word about it

be_jouster

Joined: 27 Jun 2006
Posts: 19
Helped: 1

06 Jul 2006 2:21 pic icd2 target datasheet

Maybe we can cheat the Mplab by run whole ICD with 3.3V and change a little bit resistor value (voltage divider) for the voltage monitoring so that the Mplab will see the ICD still operate at 5V. I think I need to try it.

Regards.

polymath

Joined: 02 May 2006
Posts: 236
Helped: 23
Location: England

06 Jul 2006 10:41 usb to ttl icd2

be_jouster wrote:

be_jouster

READ thread and come up with your OWN and ORIGINAL suggestions.

I just said this just 2 postings back!!!!!!
If you had read the thread you would know that MPLAB-ICD2Original combination does run the outputs at Target-Vdd and suitable for the SELECTED Device.

Polymath

polymath

Joined: 02 May 2006
Posts: 236
Helped: 23
Location: England

06 Jul 2006 21:20 icd2.5 3.3v

svlovak

You obviously DO NOT UNDERSTAND - if you did you would not ask the question.
I will try one more time to explain - I will put it very very simply just for you!

Firstly refer to ICD2-Original not one of these poor lesser designs - they are NOT Clones - Clones are identical to the original in all aspects of function and performance.

+Vdd to target is controlled by RA4 - this can only supply 5v0 to the target - this is NEVER enabled for 3v3 devices - You MUST select the correct device and uncheck the "Power target from ICD2" checkbox in MPLAB for voltages other than 5v0.
For 3v3 devices the 'checkbox' is unavailable and Target Vpp is set to 3v3 - TRY IT!

as stated earlier in thread

Quote:

my research shows:
ICD2 communicates to PIC24 and other devices at 3v3.
Target Power must be from an external supply for 3v3 devices.
The ICD2 can only supply 5V. (my Advanced Transdata PIC-ICD has variable Vdd)
Uncheck the "Power target from ICD2" checkbox in MPLAB.
Connect Debug+Vdd pin to Target +V supply.
ICD2 will sense Target +V supply (RA0).
ICD2 will scale PGC and PGD to the sensed Target +V level (Target+V <buffers> Gnd).

Why should MPLAB say anything? This function is out of the hands of an IDIOT user. If the IDIOT user selects the wrong device and ignores the MPLAB warning [ICDWarn0020] THEY deserve to fry - not the chip!

What else do you not understand?

best regards ... Polymath

szlovak

Joined: 24 Jan 2005
Posts: 22

07 Jul 2006 16:26 74ahc125 74ahct125

None of the things you were explaining in yout last post were necessary, sorry. Very Happy

So Vpp isn't mentioned in pdf. And state HIGH for MCLR is 3.3 and 5V for programming. EOT

Looking in to the schematic of original ICD2 , and this let say "clone" ( http://www.edaboard.com/download.php?id=88929 ), one cut in pcb and one wire will fix the problem. I can't test it. RC1 controls in case of pic24 3.3V, RC2 will turn on 5V for programming mode. So cutting off the path to emitter of T2, connecting it to Vdd in ICSP might work.

states for MCLR pin in original ICD2 are:

hold in reset : RC1=H, RC2=L
ICSP Vdd on MCLR : RC1=L, RC2=H
5V on MCLR : RC1=H, RC2=H

Last edited by szlovak on 08 Jul 2006 15:38; edited 1 time in total

potyo

Joined: 16 Apr 2006
Posts: 181
Helped: 10
Location: Ada, Vajdaság

07 Jul 2006 16:57 icd2 pic24f

szlovak, these connections are already mentioned before here: http://www.edaboard.com/viewtopic.php?p=644867#644867

And the logic signals for the certain output levels:
hold in reset: RC0=H, RC1=H, RC2=L
ICSP Vdd on MCLR: RC0=H, RC1=L, RC2=H
Vpp on MCLR: RC0=L, RC1=H, RC2=H
MCLR in HiZ: RC0=H, RC1=H, RC2=H

stuart83

Joined: 18 Jul 2006
Posts: 1

19 Jul 2006 21:49 microcontroller cheat sheet pic24f

Hi guys,
I came accross a similar problem a little while back on a uni project. I was using a WARP13 programmer and needed to program a PIC at 3.3V so I knocked up an adaptor board to place between the programmer and the target system. I used a MAX3378, which is basically a tri-statable bi-directional level translator. You feed two supply voltages into it and it translated bi-directionally between the two. I added a switch to select between 13V (from the WARP13) and the target Vdd to go onto the MCLR pin of the target PIC. This switch could probably quite easily be implemented electronically. The warp13 only supplied the 13V Vpp while programming, and removed it when finished (or set it to 5V - I can't remember now - I will double check if I can find the programmer), so this voltage was used to bring the MAX3378 out of tri-state during programming - This meant when programming was finished, the target system could run happily without disconnecting the programmer. You can probably still get the MAX3378 as a free sample from Maxim.
Note - I got this to work nicely for a few PIC16F and small 18F chips, but for some reason it wouldn't work reliably for a PIC18F8720 (80 pin TQFP jobbie) - I never really found out why?!?
Anyway - Heres the schematic - don't know if it will help or inspire any improvements - I hope so!
[/img]

Added after 7 minutes:

Whoops - didn't attach the schematic
Hopefully it worked this time!

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Alan69

Joined: 01 Apr 2005
Posts: 79
Helped: 4

19 Jul 2006 23:29 potyo icd2 clone

Gobol wrote:

LVC can be used to convert 5V levels to 3.3V, (but how to cope with data transmittion direction... )
maybe using simple 3.3V zeners and transistors would do the trick... ?

Just use a voltage divider, with only a couple I/O it's easy.

5V i/o ----330--+--3.3V i/o
|
660
|
gnd

LOL of course the no leading spaces messed that up. The lower resistor connects at the + .

Out from 5V the divider gives 3.3 the other side. In to the 5V input sees 3.3V as still a high, the 3.3V ouput just has the extra 660 resistor to ground. Use 2 330 ohms for the 660..

May need to double or triple these values etc for lower powered i/o pins..

That's all the 5V to 3.3V interfacing most things really need. After a few pins though the IC's still make sense..

szlovak

Joined: 24 Jan 2005
Posts: 22

21 Jul 2006 6:19 potyo icd2 klÃ³n

[quote="Alan69"]

Gobol wrote:

5V i/o ----330--+--3.3V i/o
|
660
|
gnd

LOL of course the no leading spaces messed that up. The lower resistor connects at the + .

Out from 5V the divider gives 3.3 the other side. In to the 5V input sees 3.3V as still a high, the 3.3V ouput just has the extra 660 resistor to ground. Use 2 330 ohms for the 660..

May need to double or triple these values etc for lower powered i/o pins..

That's all the 5V to 3.3V interfacing most things really need. After a few pins though the IC's still make sense..

it's not so easy. PORTC in 16f877(A) is Schmitt triggered, and it doesn't see anything below 3.58V .

polymath

Joined: 02 May 2006
Posts: 236
Helped: 23
Location: England

21 Jul 2006 9:41 pic 3.3v

Hi szlovak
I do not think Alan69 has tried his own suggestion.

The 877A Data Sheet give 0.3Vdd and 0.8Vdd as schmitt levels for all Vdd.

A Vdd of 5v =>> 1v5 and 4v0 input trigger levels.

Alan96, as svlovak says - it will not work.

regards ... Polymath

Alan69

Joined: 01 Apr 2005
Posts: 79
Helped: 4

22 Jul 2006 1:21 3v3 pic

polymath wrote:

Hi szlovak
I do not think Alan69 has tried his own suggestion.

I use it all the time, but of course on normal inputs not schmitt trigger.

I don't use PIC24, but assuming it's inputs are schmitt trigger too, I would try dropping ICD to 4.1V and inserting just series resistors into the lines. 4*.8 = 3.28, and backwards 5*.8 = 4, so you should be able to talk to both 3.3V and 5V targets without changing, let the resistors and input diodes take care of the rest. Have the ICD and targets right in front of me, I'll try it in just a little and make sure it's good, could be handy and almost no extra parts..

polymath

Joined: 02 May 2006
Posts: 236
Helped: 23
Location: England

22 Jul 2006 12:02 2v level shift

Alan69 wrote:

polymath wrote:

Hi szlovak
I do not think Alan69 has tried his own suggestion.

Hi Alan96
Yes a nice turn of phrase

Quote:

lame crap

... from you removed post.

So I was right - you have NOT tried it on 3v3 devices - re: thread name.
Having to change resistor values for each Vdd is NOT an acceptable design.

As you do not have a PIC24 device - try with 877A externally powered at 3v3 or even go to 2v0 - still within programming spec. ICD2 can do all serial PICs at all voltages.

9 res + 6 trans = 36 holes = high production cost + mega error opportunities.

regards ... Polymath

Alan69

Joined: 01 Apr 2005
Posts: 79
Helped: 4

22 Jul 2006 13:55 mplab icd2 datasheet mclr

polymath wrote:

Alan69 wrote:

polymath wrote:

Hi szlovak
I do not think Alan69 has tried his own suggestion.

Hi Alan96
So I was right - you have NOT tried it on 3v3 devices - re: thread name.
Having to change resistor values for each Vdd is NOT an acceptable design.

As you do not have a PIC24 device - try with 877A externally powered at 3v3 or even go to 2v0 - still within programming spec. ICD2 can do all serial PICs at all voltages.

9 res + 6 trans = 36 holes = high production cost + mega error opportunities.

regards ... Polymath

Pullups maybe needing lowering from an estimated design value for higher speed doesn't suggest anything about then having to change them for every Vdd. Those are only pullups, that circuit would interface 3V and 5V and 3V and 10V without changing resistors.

Again, it ONLY needed testing to make sure ICD2 wasn't expecting 'not high' when nothing was driving. Passes data fine. I tried the passing data through it, and ICD2 does fine. That it can handle 5V-5V or 3V-5V is already known from the article and previous tests. I just did a quick test to test what needed proving, redundant info wasn't on the agenda. Clear from the circuit it'll do about anything, sometimes a rose is a rose.

Brilliantly simple how that circuit goes together plus takes out some of the other parts in the ICD2, and no need for buffer chips for anyone building it from parts. I've got two copies on two different breadboards and it's pretty much a zero chance for error, I take it you didn't build it before deciding it was too much.. Holes are free where I buy PCBs, not that much for 36 even if you pay. Plus no holes for a buffer chip, not like it's that many more.

It's absolutely too good since it will do more too, I took it out. I'll do it up fully and put up a complete design in the next few days.

Alan

polymath

Joined: 02 May 2006
Posts: 236
Helped: 23
Location: England

26 Jul 2006 13:31 eicd2 usb

Alan69 wrote:

Again, it ONLY needed testing to make sure.........

I think NASA may have said this just before the explosion!

Alan69 wrote:

Clear from the circuit it'll do about anything.........

Curious - anything? sounds like precision engineering!

Alan69 wrote:

Holes are free where I buy PCBs, not that much for 36 even if you pay. Plus no holes for a buffer chip, not like it's that many more

36 holes x 100k products - na not much .... NOT! A MAJOR cost of any PCB production is Holes - fact.

Alan69 wrote:

I take it you didn't build it before deciding it was too much..

I have built one using resistors and smt - You may have noticed that smt do NOT need holes.

You are obviously aware that MChip do not warrant chips programmed outside their spec.

regards ... Polymath

bcktang

Joined: 21 May 2006
Posts: 5

26 Jul 2006 17:16 icd2.5usb icdwarn0020

Hi all,
Anyone here modified lothar stolz's ICD 2 (serial port) to support 3.3V ?

I've seen so many ICD2, and I am starting to get confused, which works and which doesnt ? or buggy?

I've constructed stolz's ICD2 clone, and require 3.3V, can I just add output buffer and the appropriate pins to make it work, or do i have to program the 877A with a different firmware ?

togarha

Joined: 04 Sep 2006
Posts: 69
Helped: 1

05 Sep 2006 7:11 icd 3v3

Hi!

First of all, congratulations for your work, I think is an incredible work to clone ICD2. I have some questions (sorry if I don't ask with sense...)

Potyo:

I'm seeing your schematics and I have some doubts:

- You conect the power supply of 74HC4066 to Vpp, but seeing the datasheet of 4066, the max power supply supported is 10V, and Vpp can go up to 13V, then we have a little problem, isn't it?

- X4 is a jumper to select what? Because I see that central pin is target Vpp, isn't it? And the other pins are icd2 Vpp (one directly and the other by 4066), then I don't understand very well what is its function (sorry for my poor understanding...).

- What is X2 and X3 meaning? And isn't possible to reduce this jumpers to only one? If always put one or the other, we can have a 15k resistor in parallel with another 15k resistor with a jumper, then when the jumper is not placed, we have 15k resistor, and when the jumper is placed we have 15k resistor in parallel with 15k resistor, then 7k5 resistor. May be is a fool idea, because I don't know what's the meaning of this resistor (I don't see anything in the datasheet, may be I skip this part), but if it isn't so small resistor we can reduce one jumper. May be we can have no placed jumpers and the idea isn't so good...

- There is any limitation in tolerance on any component (1% or it's ok with 5%-10%)??

Sorry for all questions...

Thanks a lot

Regards

togarha

PS: Sorry for my poor english

mdelfede

Joined: 29 Jul 2006
Posts: 4

11 Oct 2006 0:00 usb icd clone

I think that should be an economical and effective solution for low voltage pic operation.

ICD2 USB clone - how to get it to work with 3.3V PIC24s ???

Level shift from 2.2-5 v from target to schmitt trigger levels (~4V) in programmer is done via an open collector buffer (here a single NL17SZ07 smd, but can be any lov voltage open collector buffer). The buffer used sees an high level from 2-2.2 volt, so it's adequate for low voltage pics, I guess up to 2.5 v.

On the other side, the foltage limiting from 5v programmer to low voltage target is done with 2 diodes on Vpp-tgt and the 330R resistors; cheap and safe.

I must admit I had not yet time to test all the thing, but I'll do it on next days.

Ciao

Max

mdelfede

Joined: 29 Jul 2006
Posts: 4

18 Oct 2006 10:20 usb 3.3v voltage divider

Tested and it does work with 3.3 v pics.
For non-SMD build, the NL17SZ07 single open drain buffer could be replaced with some equivalent hex buffer in PDIP package that can be run with low voltage and tolerates 5 v on output.... pity that I didn't find any. All 7407 variant are either 5v only or in smd package.
A 5V 7407 could also be used, if powered from 5V and not from target VCC; being TTL compatible, it could detect voltages from about 2.5V as logic '1', allowing programming of 3.3v pics; future lower voltage pics (maybe 2.5v ??) would not work.

Ciao

Max

potyo

Joined: 16 Apr 2006
Posts: 181
Helped: 10
Location: Ada, Vajdaság

18 Oct 2006 20:12 icd2 vpp volt

Hi
Please test it at 2V! The original icd2 works with 2V targets.

mdelfede

Joined: 29 Jul 2006
Posts: 4

19 Oct 2006 10:21 usb on the pic24

potyo wrote:

Hi
Please test it at 2V! The original icd2 works with 2V targets.

Well, I've got no 2v pics, but the NL17SZ07 buffer does work down to 1.65V, so it should be no problem.
The only problem is that it comes in SMD package only and I don't know any low voltage open collector buffer in DIP package.

If you use a TTL input compatible 5V buffer (74HCT07 ?), it senses logical '1' only from 2.2 - 2.5 Volt; it can be used only with pics starting from about 2.8-3 V.

I think the only viable solution to have it in through-hole would be to replace the buffer with a 2-transistor discrete equivalent, or, maybe better, to use a single voltage op-amp or even better a comparator with small hysteresis. That would allow sub-1V programming.

What does make my solution cheap and easy is to separate the 2 i/o lines from 16F877A chip and to buffer ONLY the input one. That avoids the use of three state buffers to select data direction.

I did the UP level translation with NL17SZ07, but it can be replaced with some other means. The DOWN level translation is done by resistors and clipping diodes; cheaper than that I thing it's impossible Smile

Ciao

Max

TESKAn

Joined: 02 Feb 2007
Posts: 8
Helped: 1

02 Feb 2007 22:16 pic24fj & mclr reset button

Hello!
My first post here:). Anyway, to fix 3v3 problem i used simple level translator made of two NPN transistors (i used some 2N3904) and four 10k resistors - schematic and description is here http://www.edn.com/archives/1996/110796/23DI_02.htm

It works, i used one bidirectional for PGD and a 'half' translator for PGC and MCLR. So it costed me four NPN transistors and eight 10k resistors. Result? It works, tested with pic 24h, and because i use voltage from pic for lower level side i can use it to program 5v and 3v3 pics without changing anything.
I don't think you can get any cheaper than this. And probabily most of us allready have all the components at home.

TESKAn

Joined: 02 Feb 2007
Posts: 8
Helped: 1

11 Mar 2007 12:30 mplab icd 2 24f

Ok, what to do to program 3v3 or lower devices.

- make a level translator from programmer voltage to device voltage. Bidirectional for PGD and PGC (reason for PGC - done some disassembling of 877A code and found BTFSC PORTC,3 lines - looks like in some cases ICD2 tests PGC line to see it's state - my guess is it's checking to see if the line rises fast enough)

- wire programmer so the output stage gets power from target board. So MCLR has levels 0, target Vdd and module Vpp.

- ICD2 doesn't connect 13v to target, if the target doesn't support 13v on the MCLR. So there's no worry that ICD2 would fry the chip.

ADRENALIN2003

Joined: 16 Jan 2007
Posts: 24

20 May 2007 15:56 mclr vpp :low

Ok can we summ all this? Can anyone post link to sch of original ICD2, and to clone which can work with all (3v3) PIC devices?

I want to try to build one of these and it would be great if someone do this please.

Best regards!!!

potyo

Joined: 16 Apr 2006
Posts: 181
Helped: 10
Location: Ada, Vajdaság

20 May 2007 23:06 www.ada-vajdasÃ¡g

ADRENALIN2003 wrote:

Ok can we summ all this? Can anyone post link to sch of original ICD2, and to clone which can work with all (3v3) PIC devices?

You can find it in this topic: http://www.edaboard.com/ftopic161641.html

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20 May 2007 23:06 Ads

nicolas888

Joined: 10 May 2007
Posts: 1

09 Jul 2007 18:19 icd2 clone level shift

Hello.

Thank you for all informations on this forum.It's so good

I'm not an expert in ICD2 so please be tolerant.

I finish to make a potyo2 ICD2 programmer.
I'm still confuse on the '24H programming way' and mostly what is good or not.

My programmer works very well with all 8bits controler ( that is easy )
It's works well with 24H series.

I don't use the digital pot ( I still don't know why we need it ).
Can you tell me why it's needed ?

I don't use the transistor level because I've got 74HCT125 and 74HCT126 ( error in the diagram ).
Is it the suitable gates ?

I don't use the MCLR disable feature. ( I don't know why that ? )

I use the only part with the blue flag ( red flag is not equiped ).

My Vpp seems HIGH for the 24H. What do you think about that ?

Is someone see somethink missing in the schema ?

Thank you.

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Segovia

Joined: 07 Oct 2007
Posts: 4

24 Jan 2008 18:16 icd2 scheme

Hi guys
I have an original ICD2, and I found that it used 74LVC1T45 to translate the logic level.
I have test it by oscillograph and found it works perfect! You guys can search the datasheet of 74LVC1T45 for more info.

Freddie Chopin

Joined: 08 Dec 2007
Posts: 103
Helped: 6
Location: Poland / Wroclaw

24 Jan 2008 20:01 icd2 18f46k20 vdd

HCT125 and HCT126 work the same way, so why bother?

Added after 1 hours 42 minutes:

i've just tried programming PIC16 with potyo2. the voltages were given by the target, and I tried: 2.1V, 2.3V, 2.5V and 3.3V - absolytely no problems at all, but the fact remains that there is a 2.5V on the VDD line when there is no target. anyway I don't think it is a problem. very soon I'm going to test potyo2 with PIC24H [; - maybe next week.

0x41 0x56 0x45!!

IamnotJunk

Joined: 29 Nov 2007
Posts: 39

26 Jan 2008 19:21 clone usb device id

Is it possible? Clones most likely doesn't have a voltage regulator outputs.

blueroomelectronics

Joined: 17 Sep 2006
Posts: 1681
Helped: 99
Location: Toronto, Canada

26 Jan 2008 19:32 icd2 clone downloading operating system

IamnotJunk wrote:

Is it possible? Clones most likely doesn't have a voltage regulator outputs.

True, it increases the cost and complexity. The clones are aimed at home users, students and hobbyists. The majority of PIC users they never leave the 8bit chips anyways. If you need high end there are 5V dsPICs, like the dsPIC30Fxxxx.
The 24F and 33F are 3.3V chips but definitely not aimed at the beginner.