u8g_com_stm32duino_st7920_hw_spi.cpp

/*
  u8g_com_stm32duino_st7920_hw_spi.cpp

  communication interface for ST7920 4 wire SPI
*/

#if defined(STM32F1) || defined(STM32F1xx) || defined(STM32F4) || defined(STM32F4xx)

#include "u8g.h"
#include "SPI.h"

static SPISettings spiConfig;
static uint8_t msgInitCount = 2; // Ignore all messages until 2nd U8G_COM_MSG_INIT

static void u8g_stm32_st7920_hw_spi_shift_out(u8g_t *u8g, uint8_t val) U8G_NOINLINE;
static void u8g_stm32_st7920_hw_spi_shift_out(u8g_t *u8g, uint8_t val)
{
  /* send data */
  SPI.beginTransaction(spiConfig);
  SPI.send(val);
  SPI.endTransaction();
}

static void u8g_com_stm32_st7920_write_byte_hw_spi(u8g_t *u8g, uint8_t rs, uint8_t val) U8G_NOINLINE;
static void u8g_com_stm32_st7920_write_byte_hw_spi(u8g_t *u8g, uint8_t rs, uint8_t val)
{
  uint8_t i;

  if (rs == 0)
  {
    /* command */
    u8g_stm32_st7920_hw_spi_shift_out(u8g, 0x0f8);
  }
  else if (rs == 1)
  {
    /* data */
    u8g_stm32_st7920_hw_spi_shift_out(u8g, 0x0fa);
  }

  u8g_stm32_st7920_hw_spi_shift_out(u8g, val & 0x0f0);
  u8g_stm32_st7920_hw_spi_shift_out(u8g, val << 4);

  for (i = 0; i < 4; i++)
    u8g_10MicroDelay();
}

uint8_t u8g_com_stm32duino_st7920_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr)
{
  if (msgInitCount)
  {
    if (msg == U8G_COM_MSG_INIT)
      msgInitCount--;
    if (msgInitCount)
      return -1;
  }

  switch(msg)
  {
    case U8G_COM_MSG_STOP:
      break;
    case U8G_COM_MSG_INIT:
      u8g_SetPIOutput(u8g, U8G_PI_CS);
      //u8g_SetPIOutput(u8g, U8G_PI_A0);
      //u8g_SetPIOutput(u8g, U8G_PI_RESET);
      u8g_SetPILevel(u8g, U8G_PI_CS, 0);
      spiConfig = SPISettings(SPI_CLOCK_DIV128, MSBFIRST, SPI_MODE3, DATA_SIZE_8BIT); //modify for ST7920 display
      SPI.begin();

      u8g->pin_list[U8G_PI_A0_STATE] = 0; /* inital RS state: command mode */
      break;

    case U8G_COM_MSG_ADDRESS:           /* define cmd (arg_val = 0) or data mode (arg_val = 1) */
      u8g->pin_list[U8G_PI_A0_STATE] = arg_val;
      //u8g_SetPILevel(u8g, U8G_PI_A0, arg_val);
      break;

    case U8G_COM_MSG_CHIP_SELECT:       /* arg_val == 0 means HIGH level of U8G_PI_CS */
      if ( arg_val == 0 ) {
        /* disable */
        u8g_SetPILevel(u8g, U8G_PI_CS, 0);
      } else {
        /* enable */
        u8g_SetPILevel(u8g, U8G_PI_CS, 1); /* CS = 1 (high active) */
      }
      break;

    case U8G_COM_MSG_RESET:
      u8g_SetPILevel(u8g, U8G_PI_RESET, arg_val);
      break;

    case U8G_COM_MSG_WRITE_BYTE:
      u8g_com_stm32_st7920_write_byte_hw_spi(u8g, u8g->pin_list[U8G_PI_A0_STATE], arg_val);
      break;

    case U8G_COM_MSG_WRITE_SEQ:
      /*
      SPI.beginTransaction(spiConfig);
      SPI.send((uint8_t *)arg_ptr, arg_val);
      SPI.endTransaction();
      */
      register uint8_t *ptr = (uint8_t *)arg_ptr;
      while (arg_val > 0)
      {
        u8g_com_stm32_st7920_write_byte_hw_spi(u8g, u8g->pin_list[U8G_PI_A0_STATE], u8g_pgm_read(ptr));
        //u8g->pin_list[U8G_PI_A0_STATE] = 2;
        ptr++;
        arg_val--;
      }
      break;
  }
  return 1;
}

#endif // defined(STM32F1) || defined(STM32F1xx) || defined(STM32F4) || defined(STM32F4xx)