Getting By

Getting By

Getting By

A simple repository of largely nonsensical wittering. It may (or may not) be to do with what the Batsocks lot are currently using their Idle cycles for.

XMega128A4U in hi-res

ElectronicsPosted by condemned Mon, July 02, 2012 22:33:50
I've just taken delivery of some XMega128A4U chips.
These are pin-identical to the lovely XMega32A4U chips, only with 128kb flash (up from 32kb) and 8kb SRAM (up from 4kb).

The increase in SRAM is important for me, as it allows me to use a higher resolution bitmap when I'm generating video.

So... I soldered myself a special version of an BreadMate AV XMega PDI board with one of the 128s...

The 4kb in the X32A4 is enough to handle a black and white bitmap of 160 x 120:

whereas the the 8kb in the '128 will manage 320 x 180 comfortably.


I had to resort to a little subterfuge to get it working though...
Not all components of my toolchain know about the XMega128A4:

The programmer, avrdude, knows about the 128A4 smiley
The compiler, avr-gcc, doesn't smiley

Fortunately, XMegas are really impressively orthogonal. With a little care, binaries compiled for one chip will run happily on another chip. Two main things to watch out for:
a) Chips with more than 128kb flash compile slightly differently to those with less.
b) Don't use peripherals that aren't there!

I therefore compiled the XTV bitmap demo for an XMega128A3.
Avrdude was happy to upload this to an XMega128A4.

[edit: 11th Nov 2012. Atmel now have an AVR Toolchain for windows and an AVR Toolchain for Linux that supports the XMega128A4U]


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