ESP32, RA8875 and Arduino IDE

Hi all,

just a general question about the above. I few years ago I was using uno's and megas with the RA8875 display. For my latest project I will be using an ESP32. I will be using the SPI bus to communicate with the display. It appears that the Library that I had used is not compatible with the ESP32. My rather basic question is why? As I'm using the SPI bus I would assume that any device be it uno, mega or ESP32 is sending the same data to the RA8875? I'm assuming it isn't anything as simple as pin designations?

Thanks

How do you know this ?

Does the library perhaps access registers that are different between the AVR and ESP architectures ? Have you also taken into account that the AVRs are 5V devices whilst the ESP32 is a 3V3 device ?

Please post a link to the actual RA8875 display that you have bought.
Please post a link to the library you are using. (or quote the name if it is available via the IDE Library Manager)

Any conventional SPI library should work on AVR, ARM, ESP32, ...
However "elderly" libraries that assumes AVR hardware was probably written before ESP32 was invented.

The simple rules for ANY Displays question:

  1. post link to display
  2. quote library, quote library example sketch by name.

David.

Well the compiler tells me when I try to verify the sketch as in

D:\Documents\Arduino\libraries\RA8875-0.70b11/_settings/RA8875_CPU_commons.h:204:3: error: #error "your board it's not supported yet!"

and when I looked in RA8875_CPU_commons.h, as far as I can see, that error message is being generated because I'm using a ESP32 board, there is no SPI pin definition for my board, hence the question.

I will say, I've not actually hooked up the display yet, I just ran an old sketch that worked with a Mega and RA8875 just to see what would happen, I have installed the relevant ESP32 library.

Here is the link TFT 5 inch LCD Display Module w/Controller Board,Serial,I2C,RA8875 (buydisplay.com) The Library I'm using is RA8875-0.70b11.
But as I have just said I've not actually hooked the display up yet. I'm purely looking at whether this library will work with an ESP32, I have no trouble getting these display to work with UNO's and Mega's, one of the reasons is because I'm using the SPI bus as it makes it a lot easier to get things working. As for what sketch I've used, I have not use any of the RA8875 example sketches because there isn't one for the ESP32. I've used one of my own sketches that works with the Mega, it's way too big to upload here though although I could write a quick test sketch but it's not going to compile because the IDE knows I've got a ESP32 plugged in. I think you have confirmed my thoughts is that this library should work with the ESP32 via SPI if it has a SPI pin definition, almost sure it would stop the error message being generated.

Please post a link to where you got the library

Further, yes I am aware of the difference in voltages, when using the UNO and Mega I was using line shifters, the ESP32 I don't need too. As to architectures, I'm not sure it will make a lot of difference if your using SPI, but then again this is why I'm asking the experts :slightly_smiling_face:

It think it was recommended by East Rising, the displays manufacturer, GitHub - sumotoy/RA8875: A library for RAiO RA8875 display driver for Teensy3.x or LC/Arduino's/Energia/Spark

Ok, so you have the regular BuyDisplay RA8875. We only need to know Touch, Font chips, connectors etc when you attempt these items.

I am guessing that you are using https://github.com/sumotoy/RA8875

It is fairly old history. Hence it does not know ESP32
Sumotoy does not seem to have supported this for over 6 years. But there are many Forks that originated from Sumotoy's original project.

Some of these Forks might be in working order.

Otherwise I suggest that you try Adafruit_RA8875 which is also on GitHub. At least they are active.

David.

Thanks David, yes I actually have three of them, great display, yes that is the library I was using however I have just found a modified sumo library that the author claims works with the ESP32, I did not know about the Adafruit library but will definitely have a look at it, the fact that it's still active/supported is a plus.

It will if the library depends on the chip architecture

Ok, I have tried the Adafruit library and straight out of the box it does not work with the ESP32, so I tried the modified Sumotoy Library which works a treat! Happy days! Maybe the Adafruit would work if I spent a bit of time with it but as the modified Sumotoy works I'll go with that for the time being. If anyone else wants do try this it's on GitHub ESP32 and ESP8266 · Issue #136 · Sumotoy/RA8875 · GitHub When I get time I'll have a look and see what has been changed or added, just out of curiosity. Thanks, both of you, for your insight, time and patience.