I went to visit an old colleague last night, taking my Raspberry Pi and OLED display. He has a lot of groovy kit in his house such as an oscilloscope and lab power sources. After a couple of hours of debugging we concluded that … I was right! The idle-high RPi UART appears not to dovetail too well with the Picaxe’s idle-low UART. Furthermore my inverting and converting from 3.3v to 5v seemed to be correct.
So I’m going to either get hold of a Picaxe cable or get a new display. Here is where said friend kindly gave me a Nokia 5110 LCD display. “Bought 10 of these for £10 on eBay.”
He gave me a nice demo of his solution with text flashing up on it pretty quickly. Oh yes, that will be a fun toy at Christmas time.
In the meantime he showed me his Pic programmer. I quite like the idea of being able to programme a tiny cheap micro controllers to do what I want – maybe even convert a RPi’s UART to an idle low one. So on eBay tonight I’ve bought the programmer. Should be here by Christmas.