MAX7219.c

/*
 * MAX7219.c
 */


#include "max7219.h"

#define CS_SET() HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET)
#define CS_RESET() HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET)

static uint8_t decodeMode = 0x00;

static uint8_t SYMBOLS[] = {
    0x7E, // numeric 0
    0x30, // numeric 1
    0x6D, // numeric 2
    0x79, // numeric 3
    0x33, // numeric 4
    0x5B, // numeric 5
    0x5F, // numeric 6
    0x70, // numeric 7
    0x7F, // numeric 8
    0x7B, // numeric 9
    0x01, // minus
    0x00  // blank
};

static uint16_t getSymbol(uint8_t number);
static uint32_t lcdPow10(uint8_t n);

void max7219_Init_16SEG(uint8_t intensivity)
{
  max7219_Turn_On();
  max7219_SendData(REG_SCAN_LIMIT, NUMBER_OF_DIGITS - 1);
  max7219_SetIntensivity(intensivity);
  max7219_Clean();
}

void max7219_SetIntensivity(uint8_t intensivity)
{
  if (intensivity > 0x0F)
  {
    return;
  }

  max7219_SendData(REG_INTENSITY, intensivity);
}

void max7219_Clean()
{
  uint8_t clear = 0x00;

  if(decodeMode == 0xFF)
  {
    clear = BLANK;
  }

  for (int i = 0; i < 8; ++i)
  {
    max7219_SendData(i + 1, clear);
  }
}

void max7219_SendData(uint8_t addr, uint8_t data)
{
  CS_SET();
  HAL_SPI_Transmit(&hspi1, &addr, 1, HAL_MAX_DELAY);
  HAL_SPI_Transmit(&hspi1, &data, 1, HAL_MAX_DELAY);
  CS_RESET();
}

void max7219_Turn_On(void)
{
  max7219_SendData(REG_SHUTDOWN, 0x01);
}

void max7219_Turn_Off(void)
{
  max7219_SendData(REG_SHUTDOWN, 0x00);
}

void max7219_Decode_On(void)
{
  decodeMode = 0xFF;
  max7219_SendData(REG_DECODE_MODE, decodeMode);
}

void max7219_Decode_Off(void)
{
  decodeMode = 0x00;
  max7219_SendData(REG_DECODE_MODE, decodeMode);
}

void max7219_PrintDigit(MAX7219_Digits position, MAX7219_Numeric numeric, bool point)
{
  if(position > NUMBER_OF_DIGITS)
  {
    return;
  }

  if(point)
  {
    if(decodeMode == 0x00)
    {
      max7219_SendData(position, getSymbol(numeric) | (1 << 7));
    }
    else if(decodeMode == 0xFF)
    {
      max7219_SendData(position, numeric | (1 << 7));
    }
  }
  else
  {
    if(decodeMode == 0x00)
    {
      max7219_SendData(position, getSymbol(numeric) & (~(1 << 7)));
    }
    else if(decodeMode == 0xFF)
    {
      max7219_SendData(position, numeric & (~(1 << 7)));
    }
  }
}

MAX7219_Digits max7219_PrintItos(MAX7219_Digits position, int value)
{
  max7219_SendData(REG_DECODE_MODE, 0xFF);

  int32_t i;

  if (value < 0)
  {
    if(position > 0)
    {
      max7219_SendData(position, MINUS);
      position--;
    }
    value = -value;
  }

  i = 1;

  while ((value / i) > 9)
  {
    i *= 10;
  }

  if(position > 0)
  {
    max7219_SendData(position, value/i);
    position--;
  }

  i /= 10;

  while (i > 0)
  {
    if(position > 0)
    {
      max7219_SendData(position, (value % (i * 10)) / i);
      position--;
    }

    i /= 10;
  }

  max7219_SendData(REG_DECODE_MODE, decodeMode);

  return position;
}

MAX7219_Digits max7219_PrintNtos(MAX7219_Digits position, uint32_t value, uint8_t n)
{
  max7219_SendData(REG_DECODE_MODE, 0xFF);

  if (n > 0u)
  {
    uint32_t i = lcdPow10(n - 1u);

    while (i > 0u)  /* Display at least one symbol */
    {
      if(position > 0u)
      {
        max7219_SendData(position, (value / i) % 10u);
        position--;
      }

      i /= 10u;
    }
  }

  max7219_SendData(REG_DECODE_MODE, decodeMode);

  return position;
}

MAX7219_Digits max7219_PrintFtos(MAX7219_Digits position, float value, uint8_t n)
{
  if(n > 4)
  {
    n = 4;
  }

  max7219_SendData(REG_DECODE_MODE, 0xFF);

  if (value < 0.0)
  {
    if(position > 0)
    {
      max7219_SendData(position, MINUS);
      position--;
    }

    value = -value;
  }

  position = max7219_PrintItos(position, (int32_t) value);

  if (n > 0u)
  {
    max7219_PrintDigit(position + 1, ((int32_t) value) % 10, true);

    position = max7219_PrintNtos(position, (uint32_t) (value * (float) lcdPow10(n)), n);
  }

  max7219_SendData(REG_DECODE_MODE, decodeMode);

  return position;
}

static uint16_t getSymbol(uint8_t number)
{
  return SYMBOLS[number];
}

static uint32_t lcdPow10(uint8_t n)
{
  uint32_t retval = 1u;

  while (n > 0u)
  {
    retval *= 10u;
    n--;
  }

  return retval;
}