How to UnBreak my 08M..??

[besupreme]

How to UnBreak my 08M..?? *solved*

Hi,
I have a Picaxe 08M here. I didn't know if it was good so wrote the smallest program possible for a test. I think I should never have done that, though.. Picaxe runs but will never stop. - A VERY good idea, anyone?
So, please NEVER load a program like this:

  #terminal 4800
  #picaxe 08m
MAIN:
  do
    for b0=0 to 31
      pins = not pins
    next b0
  loop

I have no Idea how to stop this lousy 5kHz generator and load a new program... it always comes with eeprom error...

 

[manuka]

Simply remove the power supply (which is assumed battery in the range 3-5V), "reset" & program in something fresh! Suggest you start simply & flash a LED at pin 1 (using a suitable series dropping resistor of course!). The program below can be much refined, but is shown here in a basic form to help understanding.

LED:        'routine name
high 1      'LED on pin 1
wait 1      'wait 1 second
low 1       'LED off pin 1
wait 1      'wait 1 second
goto LED    'repeat routine

 

[srnet]

To write a new program, see the PICAXE hard reset procedure, Manual1 page 50.

 

[Erik van Gerven]

Just as easy as it is described in the manual:
- connect the picaxe to your PC and load the Picaxe Programming Editor.
- push a new programme to the picaxe but:
- switch on the '08 just after you started the download to the chip

Explanation: After a picaxe is powered up or reset it first 'listens' if the editor is connected and sending a programme. After a short period the programme on memory of the picaxe will start. This way you can break out of infinite loop programmes and re-use the Picaxe.

 

[besupreme]

Tried that about ten times now. I have a tiny piezo attached to the serout via op amp now, and I see an EEPROM test starting and quickly failing after something between 3 and 48 bytes tested. Then immediately the old program starts again..??

 

[manuka]

Is this actually a new PICAXE-08M? A tiny piezo will work OK on a PICAXE pin without an op amp! Suggest you provide a DETAILED outline (perhaps with pictures) of your layout,power supply & programming setup.

 

[besupreme]

It's just the 3 recommended resistors for programming, 220uF/100nF VSS to VDD. Nothing else. Supply 4.9-4.94V.
Added the op amp and piezo for I wanted to know if there is any communication. It doesn' change a bit if i remove this simple tester.

Always comes with failed eeprom test exactly when the old program starts. I even tried batteries and another supply now.

Test before programming said 08M Ver.2 - its not 'new' but never been used before.

Looks OK now. I grounded all other pins with a 10k resistor, and programmed programmed programmed programmed programmed . Each time the failed check was 1 to 8 bytes further down, until it finally did not restart any more. that was at about 172 bytes. Now my lil blinkenlights is loaded

 

[premelec]

Apparently you have it corrected - I'll mention that sometimes you have to wait a long time for your electrolytic capacitor to discharge or short it out to get the PICAXE to actually shut down completely when doing the hard reset.

 

[Technical]

Verification errors are always programming voltage related - check that the supply carefully and also that the 10k is on the correct side of the 22k.

 

[besupreme]

I have a 220uF and a 100nF capacitor on the supply pins, and the voltage is 4.9-5V. Checked again. The Picaxe today again is only programmable when all pins have a resistor to VDD or VSS, and I cycle power and discharge the caps. Any other approach leads to a verify error again. Once programmed, it runs. 10k, 22k, and 150R are in the right place.

I tried 3.3V, too. No change.

I'll leave this one for a project where I don't have to reprogram it.

 

[Technical]

There is still something not right with your circuit/power supply. This is not normal and so check all the soldering, particularly on the 0V ground connections - e.g. check the 0V on the download socket is connected to the 0V from the batteries There quite simply has to be a fault somewhere to give this behaviour.

 

[Goeytex]

Assuming you have the Picaxe correctly wired and no other devices attached, you could have a damaged chip but that is highly unlikely. Check the current drawn by the Picaxe. With the download cable disconnected and power applied, use your DVM to check the current drawn by the Picaxe. If it is more than about 2 ma then it probably has a blown I/O or a blown internal peripheral.

Another check which seems not to have been done is the serial port test. Select OPTIONS > Serial Port > Show Port Help Tools > Test Port. Follow the instructions in the window, but also check the voltage on the serout pin.