16x32 RGB LED Matrix counter+cpu% display

16x32display.ino

#include <Adafruit_GFX.h>   // Core graphics library
#include <RGBmatrixPanel.h> // Hardware-specific library
#include <Fonts/Arial4pt7b.h>
#include <Fonts/Arial7pt7b.h>

#define CLK 8  // MUST be on PORTB! (Use pin 11 on Mega)
#define LAT A3
#define OE  9
#define A   A0
#define B   A1
#define C   A2
RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, true);

void setup() {
  Serial.begin(115200);
  
  matrix.begin();
  draw();
}

int level = 99;
uint16_t text_col = matrix.Color333(1,1,0);
char msg[32] = "ready";
int msg_len = -1;

void loop() {
  // do nothing
  if (Serial.available()) {
    int c = Serial.read();
    if (c == '\n') {
      msg_len = -1;
    }
    else if (c == '#') {
      while(!Serial.available());
      int r = Serial.read() - '0';
      while(!Serial.available());
      int g = Serial.read() - '0';
      while(!Serial.available());
      int b = Serial.read() - '0';
      text_col = matrix.Color333(r,g,b);
    }
    else if (c == '%') {
      while(!Serial.available());
      level = Serial.read() - '0';
      while(!Serial.available());
      level = level * 10 + Serial.read() - '0';
    }
    else if (c == '~') {
      memset(msg, 0, 32);
      msg_len = 0;
      do {
        while (!Serial.available());
        c = Serial.read();
        if (c == '\n')
          break;
        if (c == '\r')
          continue;
        msg[msg_len++] = c;
      } while (msg_len < 31);
      scrollMsg();
      memset(msg, 0, 32);
      msg_len = 0;
    }
    else if (msg_len < 32) {
      if (msg_len == -1) {
        memset(msg, 0, 32);
        msg_len = 0;
      }
      msg[msg_len++] = c;
    }
  }
  draw();
}

void draw()
{
  static int offset;
  
  matrix.fillScreen(0);

  matrix.setFont(&Arial_Narrow7pt7b);
  matrix.setCursor(0, 9);
  matrix.setTextSize(1);

  matrix.setTextColor(text_col);
  matrix.print(msg);

  uint16_t col = matrix.Color333(1, 1, 1);
  matrix.drawPixel(29, 0, col);
  matrix.drawPixel(29, 1, col);
  matrix.drawPixel(29, 2, col);
  matrix.drawPixel(30, 1, col);
  matrix.drawPixel(31, 0, col);

  matrix.drawPixel(29, 5, col);
  matrix.drawPixel(30, 4, col);
  matrix.drawPixel(31, 3, col);

  matrix.drawPixel(29, 7, col);
  matrix.drawPixel(29, 8, col);
  matrix.drawPixel(29, 9, col);
  matrix.drawPixel(30, 8, col);
  matrix.drawPixel(31, 7, col);
  matrix.drawPixel(31, 8, col);
  matrix.drawPixel(31, 9, col);

  int x;
  for (x = -1; x < 32*level/100; x++) {
    matrix.drawLine(x, 12, x+1, 15, matrix.ColorHSV(1536/96*x + offset/4, 255, 160, true));
  }
  matrix.drawLine(x, 12, x, 13, matrix.ColorHSV(1536/96*x + offset/4, 255, 160, true));
  offset = (offset + 1) % (1536*4);

  matrix.setFont(&Arial_Narrow4pt7b);
  matrix.setTextColor(matrix.ColorHSV(1536/96*50 + offset, 128, 160, true));
  matrix.setCursor(24, 15);
  matrix.print(level);

  matrix.swapBuffers(false);
}

void scrollMsg() {
  matrix.setFont(&Arial_Narrow7pt7b);
  matrix.setTextSize(1);
  matrix.setTextColor(text_col);
  matrix.setTextWrap(false);

  for (int x = 32; matrix.getCursorX() > 0; x--) {
    matrix.fillScreen(0);
    matrix.setCursor(x, 10);
    matrix.print(msg);
    matrix.swapBuffers(false);
    delay(100);
  }
}