Failed picaxe 18A

[HAZELEB]

Hi technical

I have three picaxe 18A`s which will not respond to the program editor they will not respond to a download or a firmware check it just returns error hardware not found on COM 5, And they will not respond to a hard reset, The first one failed after a planed clear hardware memory, using anther 18A in its place worked fine. The second one failed after a accidental clear hardware memory I always check syntax before downloading code and clicked clear hardware instead of syntax by mistake using another 18A in its place and that worked fine and the last one failed in the same manner. The three failed 18A`s have been tested in other boards with no response it seem strange to me that they have all failed using clear hardware memory when its only supposed to over right the code. Any comments will be appreciated.

Regards Hazeleb.

 

[hippy]

Clear Hardware Memory simply downloads a program consisting of just END, so it should do nothing different to downloading any other program.

To ensure you are getting a hard reset; turn the power to your PICAXE off, wait a few seconds, start a download, wait until the Pop-Up shows "Connecting to hardware ..." in the top bar and then turn the power back on. Check that you have the PICAXE-18A and 4MHz selected through View->Options.

Which version of the Programming Editor are you using ?

 

[HAZELEB]

Hi Hippy
Thanks for the response. I am using the latest program editor version 4.1.10. I am at a complete loss as I have downloaded a lot of code to the 18A`s on this board which is an experimental LCD board powered with a 5v regulated supply with no problems until I used the clear hardware memory, as I said before replacing the 18A with a good one it worked fine for a week until I accidentally pressed the clear hardware and lost it again. I have tried the hard reset with all three 18A`s on different boards with no success. Thanks again for your response.

Regards Hazeleb.

 

[BD]

Myself and another poster have had the same problem with an 18a in recent times. The reply from technical to both of us was that it was impossible for the clear hardware memory function to effect the firmware in the chip, neverthless I will never use that function again. I would not be surprised if there is a bug in the software causing this.
The only things certain in life are death and taxes.
BD
________
BMW K1200S

 

[BD]

Myself and another poster have had the same problem with an 18a in recent times. The reply from technical to both of us was that it was impossible for the clear hardware memory function to effect the firmware in the chip, neverthless I will never use that function again. I would not be surprised if there is a bug in the software causing this.
The only things certain in life are death and taxes.
BD
________
buy silversurfer vaporizer

 

[hippy]

If it is the poster I'm thinking of, they did get their 18X working again using the power-off-on reset.

Clicking on Clear Hardware Memory is the same as deleting the contents of the Editing Form and downloading that.

When the 18A receives the data sent by the Programming Editor after Clear Hardware Memory is initiated, the 18A cannot distinguish that from any other program downloaded. From the 18A's perspective it is 'just another program'.

It is hard to see how any corruption of the PICAXE Firmware would be localised to just one particular program, with corruption not being caused by the download of other programs. It is also hard to see what failure mode under normal use could cause the PICAXE to erase or corrupt itself.

 

[Immaculan]

Hi Guys,

I sometimes get no response from my picaxes and have found it is because I use big capacitors on the supply rails (A habit from PA amplifier design), if the picaxe is in a sleep or whatever it needs a real power-up on the "searching for hardware" prompt. One way to make sure htis happens is to put a led and a 330 resistor on the supply rails to the picaxe to make sure the cap discharges on power off. This may or may not be your problem, but it is food for thought.

Best Regards

Jamie

 

[brucebolt]

I have exactly the same problem - chip won't download program!

 

[HAZELEB]

Hi Hippy
Losing an 18A after downloading clear hardware memory then replacing it with a good one and that one takes a download program ok what conclusion do I come to? And after trying numerous hard resets to no avail were do I start looking for the cause of the problem? This is so frustrating.

Hazeleb.

 

[BD]

To Hippy
Re your post 19/10/2.29
The poster with the 18x was able to recover it but was not able to recover his 18a which had failed on the clear memory command. The 18x was a replacement for the 18a as I recall. That makes 3 independent reports of the same thing happening on a clear memory command. This present thread the poster said it happened twice with two seperate chips. Whatever the cause, something seems to be happening around this command and 4.1.9 and winxp
In my own case, I had the chip running with a program flashing leds. On doing the clear memory download with the freshly installed 4.1.9, the leds stopped and I had a message on the screen "error on com1 object variable not set". Subsequent download attempts were met with "hardware not found"
error message. My replacement 18a has had several successful downloads and is running ok. I have not used the clear memory command again.
Coincidence ? who knows, but with software I wouldn't rule anything out. Bugs in software have caused planes to crash. Probably the programmers involved couldn't see how that could happen either.
BD
________
buy silversurfer vaporizer

 

[manuka]

FWIW the last Picaxe failure I had was also a (pre 18X) 18A in 2003. I don't recall the command or circuit etc, but it however was running under a W98 driven editor. It's a harsh workaround, but the most viable solution may be to cease using 18As & concentrate on the firebreathing 18X instead...

 

[hippy]

I don't want to get into a tit-for-tat argument, but the facts are not as clear-cut as you are representing them here.

The poster who had the problem with the 18A said, "I might have killed that unplugging the 3.5mm jack while power was applied (I didn't know any better at the time)", so it's by no means certain that all the problems are related to the same cause or are siftware or firmware related.

You too said, "I am thinking now that my first 18a expired because there may have been an interruption to the power supply (broken cable) during a memory clear. I also had an initial problem with the new 18a getting the same "hardware not connected message". It was fixed by simply untwisting the serial cable where it was soldered directly to the c/board", so that could have been a hardware fault; shorting the Serial Out to 0V can destroy that port pin and effectively render the PICAXE useless.

 

[BD]

The facts are EXACTLY as I represented them. There may have been a power failure but I dont know this for sure therefore it is not a fact. I do know
that the 18a failed on downloading a clear memory. That is the fact. All the rest is speculation.
I also no that two others have reported the same situation. That is a fact and that is simply what I am reporting.
People can draw their own conclusions.
________
vapormatic vaporizer

 

[BeanieBots]

Things do sometimes simply just fail. That is why PICAXES should not be used in safety critical devices. This forum has ~20,000 members which would suggest that there is a large user base of PICAXES. There are only a few reports of failure and many of those have been "user error". If there was a genuine failure rate of around 1 in 50,000, we would be getting roughly what we are seeing here. The 18A does seem to have a higher failure rate than any of the other devices. This fits my own observations as well as the collective dat on this forum.

 

[NiTrO]

I have the same problem with "Clear Hardware Memory".... If you do that you will ERASED the firmware, so It's IMPOSSIBLE to donwload any soft again. Some partners of my Work have the Same problem.
There's any conclusion for this. NEVER USE "CLEAR HARDWARE MEMORY"... I spect to delete this Option of the program...

 

[ylp88]

Are you sure NiTrO? This should not be the case. Check for other reasons that the PIC may have been wiped. Are you sure that they have been wiped, or are they just not working altogether (ie. a "fried" chip - not the potato one, mind you...).

"Clear Hardware Memory" is supposed to download a PICAXE program to the chip equivalent to:
<code><pre><font size=2>END </font></pre></code> <i>Exciting </i> , huh?

As for 18As having a &quot;high&quot; failure rate, I would gather that 18As are one of the more common chips in use as they allow the use of a directly connected LCD and have plenty of I/O options. They have also been around for a lot longer and short of the &quot;X&quot; part series for their i2c capabilities, they are very flexable and cheap! At around the price of the common plain 16F84 or 16F628, they are certainly an attactive migratory option!

<b><i>ylp88 </b> </i>

Edited by - ylp88 on 11/7/2005 11:29:06 AM