Verification error?

[picaxester]

Has anyone else had this happen to them?
I'm trying out a new USB to serial cable and it does seem to work.
I'm pretty sure I have everything hooked up right.
I'll take some pictures tomorrow after work if you need to see it.

Thank you.

 

[BeanieBots]

Could be several reasons for that error.
The most common is poor power supply but as you experimenting with a new USB cable I would suspect your serial voltage levels.
Check them with a 'scope.
If they are no greater than 5v, then try reducing the 10k in your download circuit to say 1k.

 

[picaxester]

Here's a pic of the setup.
5v power. 10k, 22k and a 100 ohm resistor. Running AXE pad on Ubuntu.
The weird thing is it works just fine when I have my logic analyser connected to it (USB).
At first I thought maybe it wasn't getting ground that's why it would work only when it was connected to the logic analyser, getting ground through the logic analyser.
The shielding wasn't connected on either end of the USB to serial converter so I ran a wire but still no go.
I've tried many different combination of resistors.
The setup works with a different converter cable. But I'd like to use these ones because I can get them for only $6.

 

[BeanieBots]

The setup works with a different converter cable. But I'd like to use these ones because I can get them for only $6.

As the saying goes:- "You get what you pay for".

If it works when your analyser is connected, it might be due to the capacitance.
Try adding 100pF to where you have the analyser connected.

 

[hippy]

What voltage is your USB to serial cable putting out on the signal line to the PICAXE ?

 

[picaxester]

@BeanieBots
I'll give that a shot after I get home from work.

@hippy
I don't have an oscilloscope. Do think it might be too low? Maybe I'll try a diode and a pull-up resistor. Do you think that might work?

Thanks guys.

 

[hippy]

Not sure how you're planning to use a diode and pull-up but I don't think it will solve the problem but post your proposed circuit so we can see how you mean.

An easy way to compensate if the USB interface signal voltage is too low for the PICAXE is to lower the PICAXE supply to 3V, 2 x AA batteries. At least for testing and getting to the bottom of the problem.

But I'd like to use these ones because I can get them for only $6.

But how much cost is incurred to yourself and others in trying to make things work, including the equivalent costs of time and effort ? One of the reasons we recommend using the AXE027 is that saving on cost can simply increase costs elsewhere.

Do you have a datasheet or a link to the module you are using ?

 

[picaxester]

The cap did the trick

Thanks!

 

[BeanieBots]

If that's the 100pF on the serial line cap, then that's enough proof that the download cable is a very bad design, shouldn't be used and explains why it's so cheap. (think about it).
Would be interesting to see whatever 'crud' it puts out on a 'scope.