Hanover FlipDot Display Arduino

flipdot.c

#include <Arduino.h>
#include <Wire.h>

#define COLS 96
#define ROWS 16
#define FRAME_SIZE ((ROWS * COLS) / 8)
#define COL_BYTES FRAME_SIZE / 8

#define FOOTER_CHAR 0x03

#define DATA_SIZE FRAME_SIZE * 2
#define BUFFER_SIZE 5 + DATA_SIZE + 3

#define MASTER_EN 9

uint8_t header[] =
{ 0x02,
  0x31,   // 0 = Text, 1 = Graphics
  0x38,   // Display Address (8 by default)
  0x00,   // Resolution Data
  0x00,   // Resolution Data
};

uint8_t data[DATA_SIZE] = {0x00};
uint8_t buffer[BUFFER_SIZE] = {0x00};

void byte_to_ascii(uint8_t b, uint8_t *twob) {
  uint8_t b1 = 0;
  uint8_t b2 = 0;

  b1 = b >> 4;

  if (b1 > 9)
      b1 += 0x37;
  else
      b1 += 0x30;

  b2 = b % 16;
  if (b2 > 9)
      b2 += 0x37;
  else
      b2 += 0x30;

  twob[0] = b1;
  twob[1] = b2;
}

uint8_t calc_crc(uint8_t *buffer, size_t len) {
  uint8_t sum = 0;

  for (int i = 0; i < len; i++) {
    sum += buffer[i];
  }

  return ((sum ^ 0xFF) + 1);
}

void setup() {
  pinMode(MASTER_EN, OUTPUT);

  Serial.begin(4800);
}

void loop() {
  uint8_t crc_b = 0;
  uint8_t resolution[2];
  uint8_t byte_ascii_buffer[2];

  byte_to_ascii(FRAME_SIZE & 0xFF, &header[3]);
  buffer[BUFFER_SIZE - 3] = FOOTER_CHAR;

  for (int j = 0; j <= 16; j++) {

    // calculate byte as two ascii values for address
    byte_to_ascii(j, byte_ascii_buffer);
    header[2] = byte_ascii_buffer[1];

    // copy into send buffer
    memcpy(buffer, header, 5);

    digitalWrite(MASTER_EN, HIGH);

    // set all to on
    memset(&buffer[5], 'F', DATA_SIZE);
    crc_b = calc_crc(buffer, BUFFER_SIZE - 2); // -2 for CRC bytes
    byte_to_ascii(crc_b, &buffer[BUFFER_SIZE - 2]); // set last two bytes to CRC
    Serial.write(buffer, sizeof(buffer));

    delay(500);

    // set all to off
    memset(&buffer[5], '0', DATA_SIZE);
    crc_b = calc_crc(buffer, BUFFER_SIZE - 2); // -2 for CRC bytes
    byte_to_ascii(crc_b, &buffer[BUFFER_SIZE - 2]);
    Serial.write(buffer, sizeof(buffer));

    delay(500);

    digitalWrite(MASTER_EN, LOW);
  }
}