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**majenko** · 21st February 2015, 10:26 AM

The display is based around the Himax HX8357 chip (http://www.crystalfontz.com/controll...nuary_2010.pdf). It is directly connected to the Parallel Master Port of the PIC32 (see the Picadillo manual for a schematic).

If you can craft a driver for the HX8357 suitable for the Microchip Graphics Library then there is no reason why you couldn't continue to use that. I have no knowledge of the internals of the Microchip Graphics Library, nor its more modern replacement, Harmony, both of which I shy away from due to licensing issues.

The initialization sequence and command codes can be lifted direct from the TFT library and used to replace the equivalent parts of an existing driver for a similar screen - the TFT library is licensed under the BSD 3-clause license - so creating a driver shouldn't be too much work.

However, you would not be allowed to distribute that driver. They only way you could do that would be if you wrote it completely from scratch and didn't include any Microchip code whatsoever.

Hence we recommend using the TFT library. You can also use 4D Workshop to create GCI/DAT based layouts and use the gciWidget library to render them - though that is limited only to simple widgets like buttons and knobs at the moment.

**dcarrington** · 22nd February 2015, 01:17 AM

Thank you Majenko for your prompt reply.

Originally posted by majenko View Post

...the TFT library is licensed under the BSD 3-clause license - so creating a driver shouldn't be too much work.
However, you would not be allowed to distribute that driver. The only way you could do that would be if you wrote it completely from scratch and didn't include any Microchip code whatsoever.

I understand and agree that lifting the driver from the TFT lib, compiling and linking it into our own application would in violation of the TFT license. However, I'm confused by the sentence about writing the driver from scratch and NOT including any Microchip code.

The Microchip Library for Applications (MLA) license allows source code modifications/additions/deletions and permits its use as long as it's used with a Microchip product. It is open source except for that restriction. Our usage would be only in the form of machine code embedded into our final product (a railroad related electronic device).

In reference to your recommendation of using the TFT lib with GCI/DAT, I will investigate to see if that is a viable solution for us. Would really be nice if that yields the best path to a solution.

Again, thank you for your help.
Don

**majenko** · 22nd February 2015, 02:23 AM

MLA is more open than Harmony, actually. With Harmony the license has this:

(b) Software License Grant. Subject to the terms of this Agreement, Microchip grants strictly to Licensee a personal, worldwide, non-exclusive,
non-transferable limited license to use, modify (except as limited by Section 1(f) below), copy and distribute the Software only when the Software is
embedded on a Microchip Product that is integrated into Licensee Product or Third Party Product pursuant to Section 2(d) below.
Any portion of the Software (including derivatives or modifications thereof) may not be:
(i) embedded on a non-Microchip microcontroller or digital signal controller;
(ii) distributed (in Source Code or Object Code), except as described in Section 2(d) below.

Lifting code from the TFT library and using it for your own ends is perfectly legitimate. You can take what you want from it and do what you want with it

**jtzeng** · 28th January 2016, 04:34 AM

Did this go any farther. Is there a driver for Harmony that can be shared?

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Use Picadillo 35T with Microchip's Graphics Library

Use Picadillo 35T with Microchip's Graphics Library

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