Monday, July 12, 2021

RPi Pico (Arduino framework) + 128x160 ST7735 SPI TFT, using TFT_eSPI library.


With Arduino Mbed OS RP2040 Boards on Arduino IDE, this post show how to connect 128x160 ST7735 SPI TFT to Raspberry Pi Pico, and control with TFT_eSPI library in Arduino framework.


The TFT Display:

The TFT display used here is a 1.8 inch 128x160 ST7735 SPI TFT. The product page is here: 1.8inch SPI Module ST7735S SKU:MSP1803.



Connection between Raspberry Pi Pico and 128x160 ST7735 SPI TFT:

The connection follow the default setup in TFT_eSPI library, Setup60_RP2040_ILI9341.h.


ST7735 TFT			Pico
Pin#	name				
1	VCC	5V/3.3V		3V3	(pin 36)
2	GND	Ground		GND	(pin 38)
3	CS	chip select	20	(pin 26)
4	RESET	reset		19	(pin 25)
5	A0	reg/data	18	(pin 24)
6	SDA	SPI data	3	(pin 5)
7	SCK	SPI clock	2	(pin 4)
8	LED	Backlight	3V3
Prepare Library, TFT_eSPI:

The library used is Bodmer/TFT_eSPI, a Arduino and PlatformIO IDE compatible TFT library optimised for the Raspberry Pi Pico (RP2040), STM32, ESP8266 and ESP32 that supports different driver chips.

To install TFT_eSPI in Arduino IDE, simple open Library Manager, search and install TFT_eSPI by Bodmer.

Take a note on the Tips section in the TFT_eSPI Library page: 
 If you load a new copy of TFT_eSPI then it will overwrite your setups if they are kept within the TFT_eSPI folder. One way around this is to create a new folder in your Arduino library folder called "TFT_eSPI_Setups". You then place your custom setup.h files in there. After an upgrade simply edit the User_Setup_Select.h file to point to your custom setup file.


Here is how I practice it:
- create a new folder in your Arduino library folder called "TFT_eSPI_Setups".
- copy TFT_eSPI/User_Setups/Setup60_RP2040_ILI9341.h to new created "TFT_eSPI_Setups" folder, rename as Setup60_RP2040_ST7735.h.


- Edit Setup60_RP2040_ST7735.h for ST7735:
//                            USER DEFINED SETTINGS
//   Set driver type, fonts to be loaded, pins used and SPI control method etc
//
//   See the User_Setup_Select.h file if you wish to be able to define multiple
//   setups and then easily select which setup file is used by the compiler.
//
//   If this file is edited correctly then all the library example sketches should
//   run without the need to make any more changes for a particular hardware setup!
//   Note that some sketches are designed for a particular TFT pixel width/height


// ##################################################################################
//
// Section 1. Call up the right driver file and any options for it
//
// ##################################################################################

// Tell the library to use 8 bit parallel mode (otherwise SPI is assumed)
//#define TFT_PARALLEL_8_BIT

// Display type -  only define if RPi display
#define RPI_DISPLAY_TYPE // 20MHz maximum SPI

// Only define one driver, the other ones must be commented out
//#define ILI9341_DRIVER
#define ST7735_DRIVER      // Define additional parameters below for this display
//#define ILI9163_DRIVER     // Define additional parameters below for this display
//#define S6D02A1_DRIVER
//#define RPI_ILI9486_DRIVER // 20MHz maximum SPI
//#define HX8357D_DRIVER
//#define ILI9481_DRIVER
//#define ILI9486_DRIVER
//#define ILI9488_DRIVER     // WARNING: Do not connect ILI9488 display SDO to MISO if other devices share the SPI bus (TFT SDO does NOT tristate when CS is high)
//#define ST7789_DRIVER      // Full configuration option, define additional parameters below for this display
//#define ST7789_2_DRIVER    // Minimal configuration option, define additional parameters below for this display
//#define R61581_DRIVER
//#define RM68140_DRIVER
//#define ST7796_DRIVER
//#define SSD1963_480_DRIVER
//#define SSD1963_800_DRIVER
//#define SSD1963_800ALT_DRIVER
//#define ILI9225_DRIVER

// Some displays support SPI reads via the MISO pin, other displays have a single
// bi-directional SDA pin and the library will try to read this via the MOSI line.
// To use the SDA line for reading data from the TFT uncomment the following line:

// #define TFT_SDA_READ      // This option is for ESP32 ONLY, tested with ST7789 display only

// For ST7735, ST7789 and ILI9341 ONLY, define the colour order IF the blue and red are swapped on your display
// Try ONE option at a time to find the correct colour order for your display

#define TFT_RGB_ORDER TFT_RGB  // Colour order Red-Green-Blue
//  #define TFT_RGB_ORDER TFT_BGR  // Colour order Blue-Green-Red

// For ST7789, ST7735 and ILI9163 ONLY, define the pixel width and height in portrait orientation
// #define TFT_WIDTH  80
#define TFT_WIDTH  128
// #define TFT_WIDTH  240 // ST7789 240 x 240 and 240 x 320
#define TFT_HEIGHT 160
// #define TFT_HEIGHT 128
// #define TFT_HEIGHT 240 // ST7789 240 x 240
// #define TFT_HEIGHT 320 // ST7789 240 x 320

// For ST7735 ONLY, define the type of display, originally this was based on the
// colour of the tab on the screen protector film but this is not always true, so try
// out the different options below if the screen does not display graphics correctly,
// e.g. colours wrong, mirror images, or tray pixels at the edges.
// Comment out ALL BUT ONE of these options for a ST7735 display driver, save this
// this User_Setup file, then rebuild and upload the sketch to the board again:

//#define ST7735_INITB
#define ST7735_GREENTAB
// #define ST7735_GREENTAB2
// #define ST7735_GREENTAB3
// #define ST7735_GREENTAB128    // For 128 x 128 display
// #define ST7735_GREENTAB160x80 // For 160 x 80 display (BGR, inverted, 26 offset)
// #define ST7735_REDTAB
// #define ST7735_BLACKTAB
// #define ST7735_REDTAB160x80   // For 160 x 80 display with 24 pixel offset

// If colours are inverted (white shows as black) then uncomment one of the next
// 2 lines try both options, one of the options should correct the inversion.

// #define TFT_INVERSION_ON
// #define TFT_INVERSION_OFF


// ##################################################################################
//
// Section 2. Define the pins that are used to interface with the display here
//
// ##################################################################################

// If a backlight control signal is available then define the TFT_BL pin in Section 2
// below. The backlight will be turned ON when tft.begin() is called, but the library
// needs to know if the LEDs are ON with the pin HIGH or LOW. If the LEDs are to be
// driven with a PWM signal or turned OFF/ON then this must be handled by the user
// sketch. e.g. with digitalWrite(TFT_BL, LOW);

// #define TFT_BL   32            // LED back-light control pin
// #define TFT_BACKLIGHT_ON HIGH  // Level to turn ON back-light (HIGH or LOW)

// We must use hardware SPI, a minimum of 3 GPIO pins is needed.
// Typical setup for the RP2040 is :
//
// Display SDO/MISO  to RP2040 pin D0 (or leave disconnected if not reading TFT)
// Display LED       to RP2040 pin 3V3 or 5V
// Display SCK       to RP2040 pin D2
// Display SDI/MOSI  to RP2040 pin D3
// Display DC (RS/AO)to RP2040 pin D18 (can use another pin if desired)
// Display RESET     to RP2040 pin D19 (can use another pin if desired)
// Display CS        to RP2040 pin D20 (can use another pin if desired, or GND, see below)
// Display GND       to RP2040 pin GND (0V)
// Display VCC       to RP2040 5V or 3.3V (5v if display has a 5V to 3.3V regulator fitted)
//
// The DC (Data Command) pin may be labelled AO or RS (Register Select)
//
// With some displays such as the ILI9341 the TFT CS pin can be connected to GND if no more
// SPI devices (e.g. an SD Card) are connected, in this case comment out the #define TFT_CS
// line below so it is NOT defined. Other displays such at the ST7735 require the TFT CS pin
// to be toggled during setup, so in these cases the TFT_CS line must be defined and connected.

// For the Pico use these #define lines
#define TFT_MISO  0
#define TFT_MOSI  3
#define TFT_SCLK  2
#define TFT_CS   20  // Chip select control pin
#define TFT_DC   18  // Data Command control pin
#define TFT_RST  19  // Reset pin (could connect to Arduino RESET pin)
//#define TFT_BL     // LED back-light

//#define TOUCH_CS 21     // Chip select pin (T_CS) of touch screen

// ##################################################################################
//
// Section 3. Define the fonts that are to be used here
//
// ##################################################################################

// Comment out the #defines below with // to stop that font being loaded
// The ESP8366 and ESP32 have plenty of memory so commenting out fonts is not
// normally necessary. If all fonts are loaded the extra FLASH space required is
// about 17Kbytes. To save FLASH space only enable the fonts you need!

#define LOAD_GLCD   // Font 1. Original Adafruit 8 pixel font needs ~1820 bytes in FLASH
#define LOAD_FONT2  // Font 2. Small 16 pixel high font, needs ~3534 bytes in FLASH, 96 characters
#define LOAD_FONT4  // Font 4. Medium 26 pixel high font, needs ~5848 bytes in FLASH, 96 characters
#define LOAD_FONT6  // Font 6. Large 48 pixel font, needs ~2666 bytes in FLASH, only characters 1234567890:-.apm
#define LOAD_FONT7  // Font 7. 7 segment 48 pixel font, needs ~2438 bytes in FLASH, only characters 1234567890:-.
#define LOAD_FONT8  // Font 8. Large 75 pixel font needs ~3256 bytes in FLASH, only characters 1234567890:-.
//#define LOAD_FONT8N // Font 8. Alternative to Font 8 above, slightly narrower, so 3 digits fit a 160 pixel TFT
#define LOAD_GFXFF  // FreeFonts. Include access to the 48 Adafruit_GFX free fonts FF1 to FF48 and custom fonts

// Comment out the #define below to stop the SPIFFS filing system and smooth font code being loaded
// this will save ~20kbytes of FLASH
#define SMOOTH_FONT


// ##################################################################################
//
// Section 4. Other options
//
// ##################################################################################

// Define the SPI clock frequency, this affects the graphics rendering speed. Too
// fast and the TFT driver will not keep up and display corruption appears.
// With an ILI9341 display 40MHz works OK, 80MHz sometimes fails
// With a ST7735 display more than 27MHz may not work (spurious pixels and lines)
// With an ILI9163 display 27 MHz works OK.

// #define SPI_FREQUENCY   1000000
// #define SPI_FREQUENCY   5000000
// #define SPI_FREQUENCY  10000000
// #define SPI_FREQUENCY  20000000
// #define SPI_FREQUENCY  32000000
 #define SPI_FREQUENCY  70000000

// Optional reduced SPI frequency for reading TFT
#define SPI_READ_FREQUENCY  20000000

// The XPT2046 requires a lower SPI clock rate of 2.5MHz so we define that here:
#define SPI_TOUCH_FREQUENCY  2500000


- Edit the User_Setup_Select.h file to point to the custom setup file, Setup60_RP2040_ST7735.h.


//#include <User_Setup.h>           // Default setup is root library folder
#include <../TFT_eSPI_Setups/Setup60_RP2040_ST7735.h>
After then, you can try examples installed with TFT_eSPI, or your own exercises.

My exercise: Pico_ST7735_SPI_128x160_.ino
/*
 * Test 128x160 ST7735 SPI TFT Display,
 * using TFT_eSPI library
 */

#include <TFT_eSPI.h>
#include <SPI.h>

TFT_eSPI tft = TFT_eSPI(); 

void setup() {
    tft.init();
    tft.setRotation(0);
    tft.setTextSize(1);
}

void loop() {
    tft.setRotation(0);
    tft.fillScreen(TFT_BLACK);

    tft.drawPixel(10, 10, TFT_WHITE);
    tft.drawPixel(10, 150, TFT_WHITE);
    tft.drawPixel(118, 150, TFT_WHITE);
    tft.drawPixel(118, 10, TFT_WHITE);
    delay(1000);
    
    int margin = 10;
    for(int x=margin; x<=TFT_WIDTH-margin; x++){
       tft.drawPixel(x, margin, TFT_WHITE);
       delay(10);
    }
    for(int y=margin; y<=TFT_HEIGHT-margin; y++){
       tft.drawPixel(TFT_WIDTH-margin, y, TFT_WHITE);
       delay(10);
    }
    for(int x=TFT_WIDTH-margin; x>=margin; x--){
       tft.drawPixel(x, TFT_HEIGHT-margin, TFT_WHITE);
       delay(10);
    }
    for(int y=TFT_HEIGHT-margin; y>=margin; y--){
       tft.drawPixel(margin, y, TFT_WHITE);
       delay(10);
    }
    delay(500);
    
    tft.setRotation(1);
    //tft.fillScreen(TFT_BLACK);
    tft.setTextColor(TFT_RED, TFT_BLACK);
    tft.drawString("RED", 10, 10, 4);
    delay(1000);

    tft.setRotation(2);
    //tft.fillScreen(TFT_BLACK);
    tft.setTextColor(TFT_GREEN, TFT_BLACK);
    tft.drawString("GREEN", 10, 10, 4);
    delay(1000);

    tft.setRotation(3);
    //tft.fillScreen(TFT_BLACK);
    tft.setTextColor(TFT_BLUE, TFT_BLACK);
    tft.drawString("BLUE", 10, 10, 4);
    delay(1000);

    
    
    delay(3000);
}


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