PC to Picaxe download error

[Rich36]

I am using the Picaxe Programming Editor to download programs to the AXE090 Experimenter Board with a 08M Picaxe chip. The program will download on the first attempt without any problem. Any further downloads usually will fail with an "ERROR - Memory verification failed. (Byte 255)" message. See attachment.

I have:
reset the 08M chip by momentarily disconnecting the power.
used a Picaxe - 18X chip.
used two different versions of the Picaxe Programming Editor.
checked the continuity of the AXE026 serial cable.
checked the placement, solder connections, shorts, etc. of the AXE090.
used two different com ports on my computer.
used different baud rates for these ports.
used a 9v ac wall transformer plugged into the jack on the AXE090.
used the battery pack for power.

Now I have run out of ideas. Does anyone know why I keep getting the error message?

The Program Editor greys out the Com1 port even though I have no programs using it. I would like to try using Com1 for downloading. How can I get the Program Editor to allow me to use Com1?

Thanks,
Rich

 

[Rich36]

After doing a search for "Memory verification failed", it was suggested that I try an AXE027 USB cable. I'll order one and give it a try.

 

[BeanieBots]

Well you've done most of the obvious checks.
When you say you've tried an 18X, are you saying that the 18X also gives the problem? If yes, then that strongly suggests a serial or power problem.
If no, then you need to suspect the 08M.

The most common cause of verification error is power supply problems.
The AXE090 has an on-board regulator. Are you using the regulator or powering direct.
What voltage is ACTUALLY being applied to the chip?
Try with 3 X 1.5v direct to the power terminals on the board.

 

[Rich36]

BeanieBots,

Thanks for responding to my request for help.

Both the 08M and 18X chips give the same memory error.

I used the AXE090 on board regularor. The measured (Multi-meter) voltage was 5v. I used a scope and looked at the V+ voltage which showed a very slight ripple. I doubt it was enough to cause any problems.

I also used the 3 X 1.5v battey pack connected directly to the AXE090. The memory error was the same.

Rich

 

[moxhamj]

This is a strange error if it works first time on a chip and then the chip can't reprogram again. Does this mean you have a whole lot of 08Ms and 18X chips lying around that you can't program any more?

If so, is it the program? Sending a program that has a Serin in it, or a very long pause or sleep loop can result in a chip appearing dead. Can you post the code?

 

[inglewoodpete]

Dr_Acula is asking what code is currently running in the chip. Some commands (not many) keep the PICAXE so busy that it is unable to check the download circuit for a new programme.

The best way to force the download to occur is to power up the PICAXE just after pressing the PE's 'Download' button.

 

[Rich36]

The AXE027 USB Download Cable works!

When I stated that programs would download to the 08M chip only on the first try, I meant first try per session. If I shutdown the computer and came back later to work on programming, the new or same program would download again on the first try. I have only one 08M chip at this time.

I am now using an AXE027 USB programming cable and have no problems downloading.