Hi
I'm trying to build an installation with seven 5"-TFT's by adafruit (5.0 40-pin 800x480 TFT Display without Touchscreen : ID 1680 : $27.50 : Adafruit Industries, Unique & fun DIY electronics and kits), connected to an Arduino Yun. The TFT's themselves are driven by RA8875 boards (RA8875 Driver Board for 40-pin TFT Touch Displays - 800x480 Max : ID 1590 : $39.95 : Adafruit Industries, Unique & fun DIY electronics and kits), that are able to talk over SPI to the Arduino.
As long as I only connect 1 RA8875 to the 32u4 of the Arduino Yun, all works well.
As soon as I connect a second RA8875, SPI gets hung up - the displays cannot initialize.
I discussed it quite a while with adafruit's support guy rick under Driving 2X RA8875 off of one microcontroller, can it be done - Page 1 - adafruit industries.
There we found out, that it is actually possible to drive more than one RA8875 - but only from Arduino UNO (Aka Atmega 328P). With other microprocessors I tried (Arduino Yun (Atmel 32u4), Teensy++ 2.0 (Atmel AT90USB1286), Teensy 3.1 (MK20DX256)), only one RA8875 can be connected.
Now I suspect that the SPI library has something to do with this problem. Has anyone an idea in what way the SPI differs in between these processors?
Thank you very much, Dani