Library for ILI9341-based TFT displays on the Espressif ESP32 native build platform

Credits

Basis: https://github.com/adafruit/Adafruit_ILI9341 This is a library for the Adafruit ILI9341 display products

This library works with the Adafruit 2.8" Touch Shield V2 (SPI)
  ----> http://www.adafruit.com/products/1651
 
Check out the links above for our tutorials and wiring diagrams.
These displays use SPI to communicate, 4 or 5 pins are required
to interface (RST is optional).

Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!

Written by Limor Fried/Ladyada for Adafruit Industries.
MIT license, all text above must be included in any redistribution

As modified by Sermus for the ESP8266: https://github.com/Sermus/ESP8266_Adafruit_ILI9341

And further modified by Rudi, et. al. for the ESP32: http://esp32.com/viewtopic.php?f=18&t=636#p2907

Extended with text rendering routines from: http://www.instructables.com/id/Arduino-TFT-display-and-font-library/?ALLSTEPS

Original hspi code: https://github.com/Perfer/esp8266_ili9341

Setup

The sample project is to be built with Espressif IDF as configured for the ESP32: https://github.com/espressif/esp-idf

ILI9341 driver

The driver itself and needed dependencies are in /driver and /include/driver. The driver is written in C++ which is not well supported by ESP8266 toolchain and sdk, so some dirty hack is needed to properly contstruct C++ objects. The code for this is in user/routines.cpp.

SPI stuff

In spite of the fact that according to the datasheet max ILI9341's clock speed is 10MHz mine robustly works at up to 40MHz so I added SPI speed prescaler macro at the beginning of hspi.c. Defining it to 1 means HSPI will be clocked at 40MHz, 4 means 10 MHz.

Sample code

*** Note: HVAC display demo is the only part being migrated from ESP8266 at this point ***

The sample code consists of two parts:

1. Rotating cube https://youtu.be/kEWThKicO0Q

2. Sample HVAC controller UI (for the extended version of this: http://habrahabr.ru/post/214257/) https://youtu.be/VraLl8XK1CI

What to demonstrate is controlled by macro UIDEMO defined at the beginning of user_main.cpp. If it's defined then the sample HVAC controller UI is shown, else, the rotating cube is rendered.

*** Note: For HVAC display demo we are using the ESP-WROVER-KIT ***

Wiring

The code uses hardware HSPI with hardware controlled CS, so the wiring shall be as follows:

ILI9341 pin --> ESP32 GPIO pin of choice
MOSI        --> GPIO13
MISO        --> n/c
CLK         --> GPIO14
CS          --> GPIO15
DC          --> GPIO2
Reset       --> pull up to 3.3V
GND         --> ground