Sharp Memory display driver for Raspberry Pi Pico SDK

This repository provides a custom driver for interfacing Sharp Memory LCD displays with the RP2040 using the Pico SDK, specifically designed to maximize performance and minimize power consumption.

The Sharp Memory Display shines with its ultra-low power consumption, and this driver is optimized to maintain that efficiency, making it well-suited for energy-sensitive applications.

• Key methods: DrawLineOfText() and DrawHorizontalLine() are crafted for speed and low power
• Additional functions: SetPixel(), ResetPixel() and DrawVerticalLine() - enable more complex rendering at a higher power and performance cost.

The driver also manages the toggling of the VCOM signal, which is required to prevent screen degradation.

Usage

Creating the Display Object

To start using the display, create an instance of the SharpMipDisplay class:

#include "sharp_mip_display.h"

SharpMipDisplay* display = new SharpMipDisplay(DISPLAY_WIDTH, DISPLAY_HEIGHT, spi1, SPI_CS_PIN);

Writing Text to the Display

You can display text using the DrawLineOfText() method of the SharpMipDisplay class. The method parameters allow you to specify the position and behavior of the text:

#include "font_16x20.h"

display->DrawLineOfText(x, y, "HELLO", kFont_16_20);

• x: The horizontal starting position of the text, specified in bytes (1 byte = 8 pixels).
• y: The vertical starting position of the text, specified in pixels.
• string: The text string you want to display on the screen.
• font: table of font which should be use
• join_with_existing_text: If set to TRUE, the new text will be added to any existing content on the same lines. If set to FALSE, the existing content within the text area will be erased and replaced with the new text. This does not affect content outside the area where the new text is placed.

VCOM Management

The VCOM signal must be toggled at least once per second to avoid display degradation. The driver automatically toggles VCOM during any draw operation. If no drawing occurs within a second, you must call the ToggleVCOM() method manually to toggle the VCOM.

display->ToggleVCOM();

Example Code

Here’s a simple example of how to create the display object and write text:

#include <stdio.h>
#include <stdlib.h>
#include <string>
#include "pico/stdlib.h"
#include "hardware/spi.h"

#include "display.h"
#include "sharp_mip_display.h"
#include "font_24x30.h"
#include "font_16x20.h"

// SPI pins
#define SPI_SCK_PIN     26U         // SCLK / SCK
#define SPI_MOSI_PIN    27U         // MOSI / COPI
#define SPI_CS_PIN      28U         // SS / CS
// Display resolution in pixels
#define DISPLAY_WIDTH   144U
#define DISPLAY_HEIGHT   168U


int main() {

    stdio_init_all();
    sleep_ms(1000);

    // Initialize SPI
    spi_init(spi1, 2000000);
    spi_set_format( spi1, 8, SPI_CPOL_0, SPI_CPHA_0, SPI_MSB_FIRST);
    gpio_set_function(SPI_MOSI_PIN, GPIO_FUNC_SPI);
    gpio_set_function(SPI_SCK_PIN, GPIO_FUNC_SPI);

    // CS pin for Sharp MIP display
    gpio_init(SPI_CS_PIN);
    gpio_set_dir(SPI_CS_PIN, GPIO_OUT);
    gpio_put(SPI_CS_PIN, 0);  // this display is low on inactive
    sleep_ms(10);

    // Create a display object
    SharpMipDisplay* display = new SharpMipDisplay(DISPLAY_WIDTH, DISPLAY_HEIGHT, spi1, SPI_CS_PIN);
    sleep_ms(1000);

    // Draw text "HELLO"
    display->ClearScreen();
    display->DrawLineOfText(0, 0, "HELLO", kFont_24_30);
    display->RefreshScreen(0,30);

    int counter{20};
    while (true)
    {
        sleep_ms(1000);
        
        if(counter < 120)
        {
            display->ClearScreen();
            display->DrawLineOfText(0,counter, "CZE", kFont_16_20);
            display->RefreshScreen(20,140);
            ++counter;
        }
        else
        {
            // Sharp Memory in Pixel display requires to toglle VCOM at least once per second.
            // VCOM is toggled in Draw methods. If no draw method is called, then it is required to call ToggleVCOM()
            display->ToggleVCOM();
        }
    }
    
    return 0;
}

Fonts

The font set for the Sharp memory display driver includes 4 distinct sizes, providing flexibility for different display requirements. Each font is covering the full range of printable ASCII characters. These fonts can be easily selected and adjusted within the driver to suit various use cases.