1.44 inch TFT Display pins

Hi there,

I am using the following display and the SD module on it:

It says to use the following pins:
-3-5V Vin connects to the Arduino 5V pin
-GND connects to Arduino ground
-CLK connects to SPI clock. On Arduino Uno/Duemilanove/328-based, thats Digital 13. On Mega's, its Digital 52 and on Leonardo/Due its ICSP-3 (See SPI Connections for more details)
-MOSI connects to SPI MOSI. On Arduino Uno/Duemilanove/328-based, thats Digital 11. On Mega's, its ----Digital 51 and on Leonardo/Due its ICSP-4 (See SPI Connections for more details)
-CS connects to our SPI Chip Select pin. We'll be using Digital 10 but you can later change this to any pin
-RST connects to our TFT reset pin. We'll be using Digital 9 but you can later change this pin too.
-D/C connects to our SPI data/command select pin. We'll be using Digital 8 but you can later change this pin too.

Why does it require me to use D/C but not MISO instead. Also, do I need to use the reset pin?

Thanks

The Adafruit TFT board contains a level shifter chip. So it can safely use 5V logic from a Uno/Mega.

The Red ST7735 boards from Ebay do not contain level shifters. So you must use 3.3V logic with these boards.

The ST7735 has a single bidirectional SDA pin that you conect to MOSI on the Arduino.
Since Adafruit has a unidirectional buffer, you can't read the SDA pin on an Adafruit board.

You can read the SDA pin on a Red ST7735 board (with 3.3V logic)
And some ARM chips have hardware to read bidirectional SPI on a single SDA pin. The AVR can only do unidirectional SPI i.e. two pins: MOSI, MISO.

Note that bidirectional pin is called SDA but is different to the SDA pin used by I2C.

The ST7735 is capable of working without DC pin i.e. 9-bit SPI. I have never seen a screen configured for 9-bit SPI. 9-bit SPI is not supported by AVR hardware.

David.

p.s. I try to give an accurate reply. The Red board owners will ignore the information. Your board is made by Adafruit and should work fine.

Ok thanks for the clarification!