Liyou Zhou / NeoPixel WS2812 5x8 Shield Driver

driver for neopixel ws2812 shield for mbed-os

Keyestudio 2812 Shield Matrix 8x5 RGB LED

Introduction

The Keyestudio 2812 Shield Matrix 8x5 RGB LED is composed of 40 individually addressable 24-bit color LEDs. It adopts stackable design compatible with UNO board. It is an intelligent control LED light source that the control circuit and RGB chip are integrated in a 5050 SMD component. It includes intelligent digital port data latch and signal reshaping amplification drive circuit. Also includes a precision internal oscillator and a 12V programmable constant current control part, effectively ensuring the highly consistency of the pixel point light color.
The data transfer protocol uses single NZR communication mode. After the pixel
power-on reset, the DI port receives data from controller, the first pixel collect initial 24bit data then sent to the internal data latch.
LED with advantages of low driving voltage, environmental-friendly, energy saving high brightness, large scattering angle, good consistency, long life span etc.

LED Specification

• Data sending speed can reach 800Kbps
• When the refresh rate is 30fps, cascade number no less than 1024 points
• The color of the light is highly consistent, cost-effective
• Built-in power on reset circuit and power-down reset circuit
• Each pixel of the three primary color can achieve 256 brightness display, completed 16777216 color full color display, scan frequency no less than 400Hz/s
• Anti-reverse protection circuit, the reverse of power supply will not damage the internal IC of the LED
• Built-in signal reshaping circuit, signals received will be wave-reshaped first and then output to the next driver, ensuring wave-form distortion to not accumulate
• IC control circuit and LED point light source uses the same power supply
• Serial cascade interface, via a signal line to complete the reception and decoding of data
• When transmission distance between two arbitrary points is no more than five meters, no extra circuit needed
• Control circuit and the RGB chip are integrated in a 5050 SMD component, forming a complete control of pixel point

Example test

1. Import the following files into an online compiler
2. Create a main.cpp and paste the following code:

#include "mbed.h"
#include "BlinkyShield.h"
int main()
{
    BlinkyShield* blinky_shield;
    uint32_t BLINKY_COLOR = CYAN;
    uint8_t BLINKY_COLOR_INTENSITY = 10;
    #define BLINKY_PIN D13

    blinky_shield = new BlinkyShield(BLINKY_PIN);
    blinky_shield->setIntensity(10);

    blinky_shield->red();
    wait_ms(500);
    blinky_shield->green();
    wait_ms(500);
    blinky_shield->blue();
    wait_ms(500);
    blinky_shield->off();
    wait_ms(500);
    blinky_shield->wipeColor(BLINKY_COLOR);
    wait_ms(500);
    blinky_shield->clear();
    blinky_shield->setTextColor(BLINKY_COLOR);
    blinky_shield->putc('A');
    wait_ms(500);
    blinky_shield->clear();
    blinky_shield->setCursor(1, 1);
    blinky_shield->putc('B');
    wait_ms(500);
    blinky_shield->clear();
    blinky_shield->setCursor(2, 1);
    blinky_shield->putc('C');
    wait_ms(500);
    blinky_shield->clear();
    blinky_shield->setCursor(3, 1);
    blinky_shield->putc('D');

    int number = 1;
    wait_ms(500);
    blinky_shield->clear();
    blinky_shield->scroll("armMbed %i", number);
    /* code */
    return 0; 
    }

3. Compile the program
4. Connect the board via USB then use the following code in the terminal to communicate with the board:

sudo cu -l /dev/tty.usbmodem -s 9600

5. Place cursor at the end of ‘usbmodem’ and press tab
6. Use one of the given numbers as your port
7. Transfer the compiled program to the board

Shazman
@LiyouZhou