increasing speed of Sanguinololu

Is it possible to run atmega644p at 20 MHZ with marlin firmware? In data sheet of atmega644p,maximum speed is 20 MHZ

Sure, if you replace the Resonator.
Then you need to set the CPU fuses for the correct frequency
And you need a 20mhz 644p profile for arduino..
Then recompile your sources (which may or may not work for the baud rates on the new freq... depends how it was written)

All for 4 more mhz which will be used waiting for data over the slow serial lines...

@Dust
Thanks for replying. what changes are needed to be done in firmware?

Looking at the gen 7 board, which is a 20mhz 644p based [reprap.org] tells me that both marlin and sprinter should work fine on a 20mhz chip

Also useful info [reprap.org], seems like standard boot loaders also have issue with faster speed. So they have provided 20mhz versions.

Also in this archive here is a boards.txt for a 20mhz chip... looks like the fuses are the same. which is nice.

Tempted to try this myself.. but don’t have any 20mhz resonators handy

Let us know how it goes.

You don't need to change the fuses (all the documentation I find says freq higher than 5Mhz, so 16Mhz or 20Mhz should both use same fuse) however you do need to specify in boards.txt the CPU frequency. I've soldered up a sanguinololu with a 20Mhz crystal and a couple of caps in place of the resonator (we were having problems) and it works well (had to change the fuses going from a resonator to the crystal as they have different drive levels)

Edited 1 time(s). Last edit at 01/03/2014 04:42AM by majic79.