Eratic characters on serial LCD

[stockley]

I'm using the serial LCD module with a picaxe 18 to write messages etc.
All works fine with standard picaxe18.
When the same program is used with an 18A it sort of works but strange characters appear at random.
If the download cable is plugged in the 18A works fine but not on it's own. I've tried other 18A's and 18x's but same fault.

Any suggestions?

 

[inglewoodpete]

Are the PICAXE18 and 18A run from the same board or different boards? Ie are you substituting just the chip on the same board?

The problem sounds like they are being run from different boards where:
* There is an earthing problem (0v rail)
or
* There is a power stability problem. Are there smoothing caps across the supply to, and mounted close to, the PICAXE.

 

[hippy]

<i>When the same program is used with an 18A it sort of works but strange characters appear at random. </i>

That sounds like a baud rate problem. The 18A has a less tightly controlled oscillator than other PICAXE's. Have a read of the AXE033.PDF on details for adjusting the baud rate.

 

[atharvai]

also check any connects on ur LCD. iut might actually be as simple as that.