Melzi MCU

I'm thinking of buying a Mendel90.
I've been very quickly poking around looking at Marlin firmware and got confused.

According to [www.hydraraptor.blogspot.co.uk] the Mendel90 Melzi MCU is an Atmega1284P.

However, the makefiles / configuration at
[github.com]
[github.com]

seem to be setting up for a 664P.

And, somewhere else (cannot remember where), I got the impression that a Atmega2560 was used.

Any clarification gratefully received.

The ones I supply have Atmega1284P. I don't use the makefile. The target is set in the Arduino IDE.

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[www.hydraraptor.blogspot.com]

The common microcontroller in Sanguino boards and their derivatives like the Melzi Ardentissimo is the 1284P which has been the case for the last 12 months or so. Whilst MARLIN will run using the 644P chip, it has to have a number of functions disabled from the code in order that it will have enough RAM to operate. Swapping the chips, (and they are pin for pin compatible), in a bog-standard SANGUINO board is relatively easy as it uses a 40 pin DIP package, normally in a socket. The MELZI on the other hand uses a surface mount chip which can make things a wee bit more difficult but not impossible. As said though, the 1284P is pretty much the defacto standard at the moment.

The Arduino Mega controller board uses an ATMEGA 2560 chip and will require a RAMPS add-on board in order to function as a RepRap controller.

MARLIN will run on both a RAMPS and a Sanguino/Melzi controller, you need to make sure that your Arduino programming software is set to the right board when compiling and uploading it.

The Nophead Dibond kits come with a MELZI board carrying a 1284P chip loaded with Nophead's variant of MARLIN as found on his GITHUB repo.

Hope this helps,

Alan

Edited 1 time(s). Last edit at 05/30/2013 10:02AM by Alzibiff.

@nophead
@Alzibiff
Thanks very much for that info. - all is clear now.

Can I ask a stupid question?
It seems to me (a very old electronics and software engineer) that most reprap controllers revolve around Arduino. I have built several NXP arm and Atmel based systems from scratch, but never investigated the Arduino world at all. What is the big benefit? Are we just using standardisation of pinouts, clock frequencies etc. Are the Arduino libraries particularly appropriate? Or is it just a legacy thing perhaps?

(I'm only asking because I have a drawer full of ARM MCU's, touch screens and wifi chippery that I was thinking about cobbling together with good old C and Eclipse as an eventual replacement for Melzi.)

It is simply because Arduino has traction in the Opensource world. The IDE is terrible and the libraries pretty amateurish. I haven't used 8 bit micros in my professional life since first 16 bit and then 32 bit got cheaper, before RepRap was born.

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[www.hydraraptor.blogspot.com]

@nophead
Ahhh! Thank you for that, I was slowly coming to that conclusion. Shame really, I have no beef against 8 bit hardware for small applications as it's so easy to code in C whilst taking full advantage of the hardware; I felt that the Arduino environment would just get in the way. For 3D printing I suspect a 32bit MCU (maybe with a lightweight RTOS) would be so much more flexible. I did see someone was working on a NXP 172X reprap controller but, alas, it wasn't available to buy.
I'm feeling a session with Kicad coming on!

The Arduino Due is 32 bit and may be of interest [arduino.cc] .