ePaper display on Photon (4.3inch e-Paper UART Module)

Hello everybody,

I played for a while with the photon and now trying to get it working with the Waveshare 4.3inch e-Paper (http://www.waveshare.com/wiki/4.3inch_e-Paper). I am struggeling with the serial communication between the photon and the display. It is working fine with my arduino. Since you have to use the serial1 ports for external communication on the Photon I had to adapt the library. But it is hard to monitor or even to debug if this is working as it should…

Has anyone experience with this kind of display? Or do you have a suggestion how to debug the serial communication on serial1 at the photon?

Thanks in advance!


I think what might be the problem is that serial1 is 3.3v. Whereas your arduino is probably 5v.
So you would need some level converting if that is the case.

@mikemoy, the wiki for the device shows that it can work with a NUCLEO-F103RB board with is an STM32F103 (like the old Spark Core) so it should work.

@nat389, you need to make sure the RX/TX lines are correctly connected. For debugging you can add Serial.print() statements that will show on the USB virtual serial port that you can connect to with a PC. Can you share a picture of your setup?

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Your problem lies in two things:
The first is that the output voltage level of the serial communication pins do not have the necessary current. (This also implies the voltage, since many users are more fixed in the voltage than in the current). You would need to use an oscilloscope to compare the serial port signals on your Arduino and your other device.

On the other one your problem can lie in the clock synchrony as I read in the page that you gave reference, can work at 9600 and 115200 (clearly these are scales used for arduino, which you will have to look for equivalence in Hz)