No Comunication with a 40x2

Hello.

I made a specific board with a Picaxe 40x2 surface micro.
It is not possible comunicate with Pic 40x2, give the error: Hardware not found on COM3!

The first time and the second time I turned on the card, I was able to download the program for Pic 40x2, but then I was never able to communicate again.

I ready test with 2 different cables (AXE027), the chip is AXE014X2SM (surface mount)

I someone can help, I am very grateful.

In attach the schema and the image of the board.
Regards
Manuel
 

Attachments

grim_reaper

Senior Member
Manuel,

Please post your code (the version that was last successfully downloaded to the PICAXE), so that folks can help.
 
Hello,
The version is: 6.0.9.2

The code is a simple code just to test the board:
==================================
#picaxe 40x2
main:
pwm C.4,150,20
pause 20
goto main
=========================
Regards
Manuel
 
Hello,

I ready make a "Hard Reset", because this board have this
function too. But i make with down power and up power.

Regards
Manuel
 
Manuel,

Please post your code (the version that was last successfully downloaded to the PICAXE), so that folks can help.
Hello,
The version is: 6.0.9.2

The code is a simple code just to test the board:
==================================
#picaxe 40x2
main:
pwm C.4,150,20
pause 20
goto main
=========================
Regards
Manuel
 

hippy

Technical Support
Staff member
Now give me a diffrent error!
View attachment 21387
Verification errors are normally an issue of power supply. It may be there is a short or circuit issue relating to the download circuit. As it was working and now isn't it is possible the PICAXE has been damaged.

Perhaps disconnect all external hardware from the board, check the supply voltage, and try again.
 

darb1972

Senior Member
You could also try powering it off 3 x AA batteries (in series - 4.5V) to completely remove all potentially external issues (such as a noisy SMPS). Do you have a Lab PSU?
 

Goeytex

Senior Member
As Hippy indicated, verification errors are almost always related to the Picaxe power supply.

Measure the supply voltage directly across the Picaxe +V and 0V pins. Do this with the programmer connected and with it disconnected. Is the voltage the same?

With the programmer connected, measure the voltage between J3-3 and V+, Is it 5V? If not then look for a bad ground or a short circuit. In most cases I have tracked down verification errors to be related to bad grounding... specifically when the AXE027 and Picaxe grounds are not tied together properly.

If the Picaxe is damaged it will generally (but not always) draw excessive current. Disconnect everything from the circuit except the Power supply and measure the current. The Picaxe should only draw about 2 - 3 milliamps with nothing connected. This may require you to desolder the LED from your board to make the measurement.
 
You could also try powering it off 3 x AA batteries (in series - 4.5V) to completely remove all potentially external issues (such as a noisy SMPS). Do you have a Lab PSU?
Yes i have a PSU. My PSU os in attach. I will try with 3 AA batteries and post here the result. Do you see my schema?123.png
 
As Hippy indicated, verification errors are almost always related to the Picaxe power supply.

Measure the supply voltage directly across the Picaxe +V and 0V pins. Do this with the programmer connected and with it disconnected. Is the voltage the same?

With the programmer connected, measure the voltage between J3-3 and V+, Is it 5V? If not then look for a bad ground or a short circuit. In most cases I have tracked down verification errors to be related to bad grounding... specifically when the AXE027 and Picaxe grounds are not tied together properly.

If the Picaxe is damaged it will generally (but not always) draw excessive current. Disconnect everything from the circuit except the Power supply and measure the current. The Picaxe should only draw about 2 - 3 milliamps with nothing connected. This may require you to desolder the LED from your board to make the measurement.
I will check only with picaxe 40x2 on board, and i come back.
 

darb1972

Senior Member
Yes i have a PSU. My PSU os in attach. I will try with 3 AA batteries and post here the result. Do you see my schema?
Hello Manuel

That PSU looks fine. I have heard of the brand but not used it. I am sure that being a Lab PSU it would have a clean output. I was just concerned that you might have been using a crappy SMPS plug pack or something of that nature.

I hadn't looked at your schematic until now. I noticed that on the Serial In connection, the 10k to Ground doesn't "look" quite right in terms of my experience with schematic capture software. As it is pictured, it doesn't look centered on the node. With my experience that can (sometimes) mean that although it looks connected, it isn't actually correctly connected to that node and could even be "floating". Depending on your PCB layout software, if it has DRC (Design Rule Check) and you didn't carry out a DRC, then something like this could be missed and carry over to the layout.

I looked at your layout, and although I think it looks right, if I were you, I would carry out the following steps (with POWER OFF to your project);

* Use a good quality DMM (Digital Multi Meter) and on the ohms scale (not continuity) put one probe on the Ground of your PSU (at the PSU end) and then probe around the Ground connection/s to the PICaxe and programming port. Obviously you are looking for near zero ohms.

* If you have a microscope, look at all of your SMD connections including ALL of the Pins on the PICaxe.

Another thing, what PCB layout software did you use? I'm no Engineering Guru, but, I'm fairly certain that vias (through holes) are a bit of a "no no" when placed in the middle of an SMD pad. A DRC would have likely flagged this as an issue. It might look good and efficient, but when you install the SMD component, you might accidentally fry your connection from one layer to the next. So with that in mind, I would check for very low ohms along ALL of the tracks from the programming port to the Serial Out, and from the programming port to the first resister, then from the other side of the 22k resistor to Serial In. From memory, you had at least one via in the middle of a pad on at least one of the resistors in the programming port arrangement. Basically check EVERYTHING (again if need be).

The only time I have ever come across vias in pads is when there were MANY put on a large pad and then they connected to another large pad on the other side. This was being used as a heatsink. Even if one of the vias got damaged, there were dozens involved so that ensured some degree of connection (albeit for heat as opposed to electronic connection).

Also, depending on who manufactured your board, some manufacturers will do a "bare board electrical connection check" which verifies the integrity of the PCB, whereas other might not carry out this test, meaning that small breaks in tracks (either due to manufacturing issues or design errors) or vias that look o.k. but fail to conduct from one side to the other might actually exist on your PCB. I wouldn't assume your PCB is o.k. You really need to double check it.

Let us know how you go.

Regards
Brad
 
Hello Brad.
Thanks for the tips you gave me.
I use diptrace to make this pcb.
I will check all with care again, when I have answers and solutions I report here.
Best Regards
Manuel

Hello Manuel

That PSU looks fine. I have heard of the brand but not used it. I am sure that being a Lab PSU it would have a clean output. I was just concerned that you might have been using a crappy SMPS plug pack or something of that nature.

I hadn't looked at your schematic until now. I noticed that on the Serial In connection, the 10k to Ground doesn't "look" quite right in terms of my experience with schematic capture software. As it is pictured, it doesn't look centered on the node. With my experience that can (sometimes) mean that although it looks connected, it isn't actually correctly connected to that node and could even be "floating". Depending on your PCB layout software, if it has DRC (Design Rule Check) and you didn't carry out a DRC, then something like this could be missed and carry over to the layout.

I looked at your layout, and although I think it looks right, if I were you, I would carry out the following steps (with POWER OFF to your project);

* Use a good quality DMM (Digital Multi Meter) and on the ohms scale (not continuity) put one probe on the Ground of your PSU (at the PSU end) and then probe around the Ground connection/s to the PICaxe and programming port. Obviously you are looking for near zero ohms.

* If you have a microscope, look at all of your SMD connections including ALL of the Pins on the PICaxe.

Another thing, what PCB layout software did you use? I'm no Engineering Guru, but, I'm fairly certain that vias (through holes) are a bit of a "no no" when placed in the middle of an SMD pad. A DRC would have likely flagged this as an issue. It might look good and efficient, but when you install the SMD component, you might accidentally fry your connection from one layer to the next. So with that in mind, I would check for very low ohms along ALL of the tracks from the programming port to the Serial Out, and from the programming port to the first resister, then from the other side of the 22k resistor to Serial In. From memory, you had at least one via in the middle of a pad on at least one of the resistors in the programming port arrangement. Basically check EVERYTHING (again if need be).

The only time I have ever come across vias in pads is when there were MANY put on a large pad and then they connected to another large pad on the other side. This was being used as a heatsink. Even if one of the vias got damaged, there were dozens involved so that ensured some degree of connection (albeit for heat as opposed to electronic connection).

Also, depending on who manufactured your board, some manufacturers will do a "bare board electrical connection check" which verifies the integrity of the PCB, whereas other might not carry out this test, meaning that small breaks in tracks (either due to manufacturing issues or design errors) or vias that look o.k. but fail to conduct from one side to the other might actually exist on your PCB. I wouldn't assume your PCB is o.k. You really need to double check it.

Let us know how you go.

Regards
Brad
 

hippy

Technical Support
Staff member
That it previously worked but now does not, and a Hard Reset does not resolve the issue, it would seem there is either a fault on the board or the PICAXE chip is damaged.

Apart from suggesting checking continuity of the board, looking for shorts and broken tracks, I am not sure what the best way to proceed is.

Under normal circumstances one would suggest removing the chip and testing that on breadboard, replacing the PICAXE chip and seeing if the replacement works. Not so easy with a surface mount device.

Perhaps build another board and see what happens with that. If it works that is great. If it works but then also stops working that would indicate some systemic issue with the board, circuit, or program.
 

newplumber

Senior Member
Manuel Pinto said:
Now give me a diffrent error!
Hi

I had the same error when downloading a program and my power was disconnected (it then said pay late power bill jk)
so reading all the pros helping you ... it seems from my rookie view ...your circuit board power seems to be unstable when programming the 40x2
would adding more capacitors work? IMHO it is very unlikely you would damage a awesome 40x2 because it is almost bullet proof
(well not quite I have a few with holes in them :) ) but I brainlessly hooked up the power backwards to a few in short times and they keep working fine
I sure hope its a easy fix for you tho ....mine all have been (of course I never fix it...this forum does :) )
your friend without 2 cents Mark
 

hippy

Technical Support
Staff member
I ready change the chip PICAXE 40x2 (2 times), and the problem continue.
It may help if you can describe the full history and events. For example was it giving "Cannot find hard hardware" error, you replaced the chip, then started getting "verification" errors ?

If so that would suggest the change occurred as a result of the replacement.
 

inglewoodpete

Senior Member
As several members have mentioned already, the likely cause of the problem is power related.

I note that you are using a laboratory power supply. Does it have current limiting? If so, is it adjusted to supply enough current for your project? If the power supply current has a current limit, the voltage may drop at times of high load, affecting the program downloads.
 
The power supply has current and voltage limiter! I'm just using the voltage limiter obviously, but I do not use a current limiter. Be it, the circuit eats the current need!

As several members have mentioned already, the likely cause of the problem is power related.

I note that you are using a laboratory power supply. Does it have current limiting? If so, is it adjusted to supply enough current for your project? If the power supply current has a current limit, the voltage may drop at times of high load, affecting the program downloads.
 

premelec

Senior Member
Looking at your board layout i think you have many possibilities of PCB defects... even small lead crack or or tiny whisker short etc... not much room for error. i suggest going over the PCB completely with continuity meter and visual with microscope. What is the maximum current you run on the PCB traces? and on the overall board?
 

kranenborg

Senior Member
I second Premelec's remark. The Picaxes are very reliable devices by themselves, and a battery power supply is a very stable source too. I had a very frustrating experience only once, and in the end it was a tiny solder blob that caused the trouble ...

BR, Jurjen
Http://www.kranenborg.org/electronics
 
Hello.
The maximum current consumed in the total at this time is 0.029Amp. At this time I do not have an individual consumption, as I am still analyzing the board. (my time is not much, unfortunately)

Looking at your board layout i think you have many possibilities of PCB defects... even small lead crack or or tiny whisker short etc... not much room for error. i suggest going over the PCB completely with continuity meter and visual with microscope. What is the maximum current you run on the PCB traces? and on the overall board?
 
Hello,
I believe! Well I've done several experiences with common component boards and the result was fantastic! Now it's my second experience with SMD components, and it does not work very well! I am seriously thinking of going back to the old school of common components.


I second Premelec's remark. The Picaxes are very reliable devices by themselves, and a battery power supply is a very stable source too. I had a very frustrating experience only once, and in the end it was a tiny solder blob that caused the trouble ...

BR, Jurjen
Http://www.kranenborg.org/electronics
 

premelec

Senior Member
best to figure out what happened - probably not due to SMD per se - but due to layout etc... In any case i hope you persist with your projects and learn in the process... we all make stuff that doesn't work at times... and figure out what went wrong... ;-0
 

newplumber

Senior Member
Hi
I'm with premelec ..."best to figure out what happened" ...
whats amazing about this forum is the pros here can fix things with out schematics, pictures and google search but it makes it soooo much harder for them
pictures are worth a 1000000 words

@ Manuel Pinto ... you have like (i'm guessing) many hours into this project which is cool
but wouldn't it be great to figure out what is wrong... maybe for you its to big of challenge but you have all the help you want here
I guess for me ...I never started a project and it worked flawlessly the first time (if it did I would be scared)
anyway my little thought
Mark
 
Hi,

I always learn from my mistakes. It's not the first time, and it should not be the last one I learn this way.
I discovered several errors in passing the schematic to the pcb!
I developed a new pcb, with the connections to components manually.
When I solve the whole process, I post it on the forum.
Thanks for the support,
Manuel
Hi
I'm with premelec ..."best to figure out what happened" ...
whats amazing about this forum is the pros here can fix things with out schematics, pictures and google search but it makes it soooo much harder for them
pictures are worth a 1000000 words

@ Manuel Pinto ... you have like (i'm guessing) many hours into this project which is cool
but wouldn't it be great to figure out what is wrong... maybe for you its to big of challenge but you have all the help you want here
I guess for me ...I never started a project and it worked flawlessly the first time (if it did I would be scared)
anyway my little thought
Mark
 

newplumber

Senior Member
Sweet good to hear Manuel ... yes if you can post some pictures and info
then maybe even I can learn something
 

darb1972

Senior Member
Hello Manual

Sorry for the delay in replying. I've been very busy and lost track of this tread.

Sounds like you might have found issues with the PCB as I suggested back in post #14. Did you run the DRC in Diptrace? Did you get errors on any of your track joins and/or where you had vias under SMD pads? The DRC will highlight these as errors and circle them in red.

If you are going to stick with SMD designs, I would strongly suggest you invest in a good quality microscope. Perfect for finding microscopic issues.

Regards
Brad
 
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