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Panelolu2 for Melzi and nopheads marlin

Posted by m237b 
Panelolu2 for Melzi and nopheads marlin
March 03, 2015 10:10AM
Hi guys,

Hope some of you have experience of running Octoprint (RaPi2) and Penelolu2. I have an issue of a very slow transfer
speed when I copy/load gcode file into SD card hosted on Penelolu2. For example 5MB file would take some 10-13 min
to get copied into SD. Any idea how that can be corrected ? or improved ?

Thanks in advance
Re: Panelolu2 for Melzi and nopheads marlin
March 03, 2015 03:30PM
The bottleneck is Marlin on the 8 bit 16 MHz AVR chip. There is no easy way to make it faster. Going via the P2 is no overhead.

My experience with OctoPrint on RPi is the USB is 100% reliable so I just upload to the RPi and print over USB.

To put files on the Melzi SD card I plug it into my PC unless it is a short file. If you don't have a PC nearby you could plug it into a USB port on the RPi and load it much faster.

I find with anything I design in OpenScad USB is fast enough as I limit segments to 0.5mm with $fs. Also I think Skeinforge merges short segments. The only time I found USB not fast enough is when printing Owls and Yoda sliced with Cura, which gave ridiculously short segments.

The other thing to be careful of is the RPi camera can use all the CPU if you don't limit its bandwidth.

Edited 2 time(s). Last edit at 03/03/2015 03:33PM by nophead.

Re: Panelolu2 for Melzi and nopheads marlin
March 03, 2015 03:44PM
Also it is slightly faster with a direct serial connection via the GPIO to the expansion connector running at 115KB than it is via USB at 250KB. A poor indictment of USB!

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