I just threw away a good Picaxe 14m

[alhoop]

I had two of the old Picaxe 14m chips - one operating in a circuit and one for a spare. I attempted to program the spare and got
the 255 error so I threw the chip away. Later I pulled the working 14m and got the same results.
I moved the programming station from a Dell Inspiron 600 to a Shuttle XPC computer and had no problems programming.
This was the first time I had attempted to program one of the old chips on the Dell PC, all my M2 (08,14,18,20 and a 20X2) chips program with no problems.
This tells me that the USP ports on my Dell PC supplies less power than the Shuttle PC. Do the old Picaxe chips require more power
to program(how much is enough?) than the new M2 devices or am I living on the hairy edge when using the Dell?
Al Hooper

 

[hippy]

I am guessing by "the 255 error" you mean a verification error; if so that's usually that the PICAXE chip itself getting insufficient power, usually battery powered with those batteries at the end of their lives.

All PC USB ports should be able to provide at least 100mA at 5V and support up to 500mA. The FT232RQ used in the AXE027 should only require 15mA and the current injected through the download interface is minimal, about 300uA.

Voltage can play a part if a signal is not high enough to convince the chip the input pin is taken high but a USB port should normally be 5V or very close. The 14M is not Schmitt triggered on the Serial In so any voltage over 2V on that pin would be expected to work.

Two things you could try with the Dell PC is running a cable test to check what the actual output voltage is, and perhaps try programming with the 14M powered by 4.5V, 3 x AA batteries. If running the AXE027 through a hub it may be worth trying it direct to the PC.

 

[nick12ab]

What circuit are you using?

Does it have a decoupling capacitor? No decoupling can often result in bizarre behaviour that makes no apparent sense, so they should always be included regardless of whether or not the circuit worked the first time without one.

 

[bpowell]

I've blown one up trying to run it from -5 VDC...it's the only one I've killed.

 

[manuka]

FWIW - I've been educationally PICAXEing ~13 years, mostly at senior high school & first year polytech/university level. Almost all setups (perhaps 1000's of them) have been 2 or 3 x AA battery powered.

Learning blunders however have predictably abounded, especially connecting a 9V battery to that just too tempting "snap", incorrect supply connections or even running from 12V. Best forgotten are soldering botch-ups & even attempts to supply from an AC plug pak! Decoupling caps. have been used when justified, but left out for simpler work (433 MHz etc) .

AFAIK (& in contrast to classic woes associated with discretes, TTL logic ICs, 555s, 741s, BASIC Stamps, wireless modules, "other" micros, audio ICs etc), not a single PICAXE has gone belly up.

These little darlings have shown themselves to be near bullet proof! Old chalkie Stan.

 

[alhoop]

I also threw away a Picaxe 08m for the same reason. I now have a Picaxe 18x that acts the same way - gives the 255 error when I try to program
on a Dell PC and programs fine on a Shuttle XPC. Evidently it is not low USB power as I suspected. I have a TopWin 2000 programmer that warns when
USB power is low(depending on type chip being programmed) so I built a 5 volt Booster for the USB line and it made no difference here.
I do have a bypass capacitor directly across the voltage and ground pins of the chip being programmed. I'm using a Heathkit Digital Equipment experimenter ET3200 to program the chips on the breadboard. I have tried it with the ET3200 internal 5 volt supply through a 1N4004 and also tried using a YH3050 power supply. I am not using the Picaxe AXE027 USB cable but if that is the problem why would it work on another PC? That's the only difference except Win 7 on the Dell and XP on the XPC.
Thanks to all who responded - I guess this is of limited interest to most as the legacy chips are probably almost gone - I only have four left.
Al

 

[premelec]

Al - I have been programming some legacy 08M chips on 3.6v Li battery with no problem - I've only had one chip failure - a 14M2 driving an AP102 LED string - I think something may have fed voltage back from one of the two signal lines - so I put 300 ohms in series with each and have had no further problem.

 

[techElder]

... I am not using the Picaxe AXE027 USB cable but ...

How can RevEd make it any easier to program a PICAXE? Do it the way they recommend and everything works fine.

How is what you are doing saving you anything?