Teensy 3.1/LC with Waveshare 1.54 inch e-paper display

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andydasmith

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Hi, I've seen on this forum that it is possible to get this display to work with the 3.1/3.2/LC using Ziggy's GxEPD library. I've had no luck so far after compiling the example code and uploading it to a Teensy 3.1. The software runs but always returns "BUSY TIMEOUT" with the pin configuration given in this forum by ANDYUK:
Working pin mapping as follows;
E-paper > Teensy 3.2
Busy > 7
RST > 9
DC > 8
CS > 10
CLK > 13
DIN > 11

This is different than given in the Waveshare documentation for the Arduino UNO:pin mapping as follows (RST and DC are reversed);
E-paper > Teensy 3.2
Busy > 7
RST > 8
DC > 9
CS > 10
CLK > 13
DIN > 11

I've tried both ways with and without the code changed in the example:
GxIO_Class io(SPI, /*CS=*/ 10, /*DC=*/ 8, /*RST=*/ 9);
GxEPD_Class display(io, /*RST=*/ 9, /*BUSY=*/ 7); I've also tried bridging both the 3-wire and 4-wire jumper on the display, it was supplied set to 4-wire SPI.

I've tried swapping the pin assignments both ways with no success.
The display arrived with nothing displayed, others report it is supplied with the demo screen still written. This, together with the fact that I always get Busy Timeout makes me suspect that the display is defective. (I've tried disconnecting the Busy line and the software reports that is drawing the pictures on the display but nothing is shown.....so the display is holding the Busy pin high.
Before I send the display back for a replacement I thought I'd ask if anyone has had similar problems.
 
To finally check the display I connected it to an Arduino nano and loaded the Waveshare demo. It worked perfectly.
I suspect there may be something wrong with the pin connections I'm using to the Teensy boards that I've tried (3.1, 3.2, LC) that are given in my first post. I got these from a post on this forum by ANDYUK.
I've been reduced to trying random pin connections but have not managed to get any change to the data left on it from the Waveshare data demo.
Once again, I'm using the GxEPD library and running the GxEPD_Example.ino, and powering the display from the Teensy 3.3v.
If anyone sees this who has managed to get the display working with a Teensy I'd really appreciate some help.
 
Hi Andy, saw your question on the other thread also.
Did you try to run the Waveshare demo ino, which you ran successfully on the Nano, on the Teensy also? From your posts above, I can't tell for sure if you did.
One other thing: the Nano operates with 5V I/O pins, the Teensy on 3V3 I/O pins. Did you hookup the VCC pin of the display to the 3V3 pin of the Teensy?

Regards,
Paul
 
In cases like this it always helps to see things like photos of your setup and maybe pointers to what display you have, hopefully with documentation
And which library and example sketch you are trying.

Otherwise it is sort of hard to guess what is going on.

For example I would assume that you have also hooked up some form of power pin and ground. What voltages does this display require?
What Voltages does it need and output on IO pins? If 5V than T-LC might have problems as it's pins are not 5v tolerant. But also if the display requires +5v on IO pins, the Teensy boards output 3.3v signals, so potentially might require some level shifters...

Note: My quick goggle of: Ziggy's GxEPD library
Did not give me anything.
 
Andy needs to confirm but I assume this is the display and this is the library he is referring to.
The display however comes in 2 versions which are not code compatible...
From the Waveshare product page:
"The 1.54inch e-Paper is updated to 1.54inch e-Paper V2 version. Codes of the two version are not compatible with each other. Except for the controller and codes, the new V2 version is exactly the same as the old one. If you are users of the old version, you need to update your codes as well for your new order".
 
Thanks very much for the replies.
I did try running the Waveshare demo (epd1in54_V2.ino for ARDUINO UNO) on the Teensy and it works without modification. So that proves I have the correct pin connections....PROGRESS!
For the GxEPD preferred library at https://github.com/ZinggJM/GxEPD I am using latest ver 3.0.9. I was using this old version because I saw posts on this forum that the new GxEPD2 version didn't compile for Teensy
It could be that as I have V2 of the display it is no longer compatible with the 3.0.9 code which has been replaced by the GxEPD2 version.
I'm trying now to make sense of the Waveshare C++ library to see how I can display numbers......that's all I wanted to do before I ran into this problem
 
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