first I have to admit that I am a very new in terms of microcontrollers and Arduino and thus I hope my question is not too stupid and is placed at the correct place in this forum.
In my first steps I tried to realize a simple clock by getting time and temperature from a RTC (DS3231, connected via I2C) and display both on a TFT. It worked fine with my Nano and a 0.96 inch OLED-Display. Due to further development I wanted to use a larger display and bought an Arduino Uno and a 2.8 inch TouchScreen shield (Elegoo, ILI9341) which uses parallel communication. What I undestand is that parallel means I have to connect 8 pins for data transfer. But what are the LCD_CS, LCD_RS, LCD_WR and LCD_RD connections for? By googling this stuff I got the impression that this is a serial connerction (like CS, TXD, RXD) but it also have something to do with UART (which is a great mystery in my young µC carrer). If I am right, why is this display using serial AND parallel communication?
There is also a SPI interface at the display for the SDcard reader but I do not need it so far.
The example sketches work fine but now to my essential question:
I would like to connect the shield for the first try by jumper cables (and it works fine). Later I want to use a serial/parallel interface and I think that should be possible.
BUT when I start the RTC in the sketch setup by "clock.begin();" the display does not do anything anymore. I do not understand whats going up there. The RTC is connected via I2C to the I2c pins which are not used by the display. What interaction (software/hardware) inhibits the use of both devices at the same time?
Hope you will not blow me apart!
Many thanks in advance!