Custom Host software
June 22, 2010 12:32PM
Hi all,

i am trying to build a custom host software for the reprap motherboard with firmware version 1.6. Could somebody please point me to the exact communication protocol for the reprap. i know the host software sends the gcode to the motherboard but i am not sure of what the reprap sends back as confirmation for the line of gcode received. i am also not sure of what format the gcode is sent to the motherboard (does sending g1 x12 y12 z12 via a serial terminal move the tool head to the specefied co-ordinates).

thanks in advance.

Re: Custom Host software
June 22, 2010 01:24PM
The protocol (set of accepted GCode and what it does) changes over time and differs between firmware variants.

There are relevant wiki pages which may help, such as Mendel_User_Manual:_RepRapGCodes; reading the firmware source code for your firmware of choice is probably the more reliable way to determine exactly what it accepts and does.

Re: Custom Host software
June 23, 2010 01:27PM
Thanks for the link. that helps a lot but still there is no mention of the confirmation messages of reprap
Re: Custom Host software
June 23, 2010 01:36PM

i have found one more problem. the reprap motherboard i have seems to behave strangely. the green power led glows only when the reprap firmware is on the board with any other sanguino code like a blinky or something the power led does not come on. i am really not able to figure this out from the schematics. i am just using a normal atx supply

Re: Custom Host software
June 23, 2010 02:22PM
Reprap firmware consumes (a subset of) GCode similarly to other GCode-using CNC machines worldwide. What sort of confirmation messages from the microcontroller are you expecting or hoping will be there? For more general info on GCode, read its reference docs such as, although note that current RepRap firmware does not implement GCode fully according to these standards. Your most accurate reference for what your firmware does is the source code of that firmware smiling smiley

The assembled Makerbot electronics boards are built assuming an ATX power supply and soft PSU switching -- that is how the MakerBot Cupcake does things. This approach assumes you will also use the Makerbot firmware (I think). Did you read the wiki page about the Makerbot electronics and the modifications for use with Mendel? If you want "Mendel-style" electronics you can modify the boards. (BTW that page was apparently fairly radically edited 3 days ago, adding a lot of info on more-or-less staying with MakerBot style electronics instead... I have not read the updated version in detail yet).

Before even thinking about writing "custom host software", it will help to read as much of the wiki as you can, so you have enough background information for what you are hoping to do. You will also want to use (and probably read the source code of) existing host software and investigate what it does, and how it interacts with the microcontroller.

Re: Custom Host software
June 23, 2010 02:35PM
One more thought: You can easily test by using a serial terminal emulator, and see what happens. Something as simple as a screen /dev/ttyUSB0 command from a (Linux bash) shell window should be enough to get you communicating with your RepRap microcontroller. Then type GCode at it, and see how it responds.

Re: Custom Host software
June 24, 2010 04:16AM

Pin 14 controls the ATX power supply.

Add this code to any Sanguino code you write. And of course do not use pin 14 for anything else!

#define PS_ON_PIN 14

In setup() add

pinMode(PS_ON_PIN, OUTPUT); // add to run G3 as built by makerbot
digitalWrite(PS_ON_PIN, LOW); // ditto


Re: Custom Host software
June 24, 2010 02:34PM
Thanks ....that did the trick.
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