SatclockRS41/radio.c

//
// Created by SQ5RWU on 2016-12-24.
//

#include "radio.h"


uint8_t _spi_sendrecv(const uint16_t data_word)
{
  GPIO_ResetBits(GPIOC, radioNSELpin);
  // wait for tx buffer
  while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET) continue;
  SPI_I2S_SendData(SPI2, data_word);

  // wait for data in rx buffer
  while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET) continue;
  GPIO_SetBits(GPIOC, radioNSELpin);
  return (uint8_t) SPI_I2S_ReceiveData(SPI2);
}


inline uint8_t radio_rw_register (const uint8_t register_addr, uint8_t value, uint8_t write)
{
  return _spi_sendrecv(((write ? register_addr | WR : register_addr) << 8) | value);
}


#if 0
void radio_set_tx_frequency_int (long freq)
{
  if ((freq < 240000000) || (freq >= 960000000))
    return;

  long hz = (30L*freq) / SI4032_CLOCK; /* off-spec 26MHz xtal in the RS */
  int hbsel, freqband, off, f;

  hbsel = (hz >= 480000000) ? 32 : 0;

  if (hbsel)
    {				/* high band select 480-959.9 */
      freqband = (hz - 480000000) / 20000000;
      off = hz - (freqband * 20000000);
      f = (off * 32000) / 20000000;
    }
  else
    {				/* low band 240-479.9 */
      int a = hz - 240000000;
      int b = a % 10000000;
      int c = a / 10000000;
      int d = (32000 * b) / 10000000;

      freqband = (hz - 240000000) / 10000000;
      off = hz - (freqband * 10000000);
      f = (off * 32000) / 10000000;
    }

  radio_rw_register(0x75, (uint8_t) (0b01000000 | (fb & 0b11111) | hbsel), 1);
  radio_rw_register(0x76, (uint8_t) (((uint16_t)fc >> 8) & 0xff), 1);
  radio_rw_register(0x77, (uint8_t) ((uint16_t)fc & 0xff), 1);
}
#endif


void radio_set_tx_frequency (float freq_in_mhz)
{
  uint8_t hbsel = (uint8_t) ((freq_in_mhz * (30.0f / SI4032_CLOCK)) >= 480.0f ? 1 : 0);
  uint8_t fb = (uint8_t) ((((uint8_t)((freq_in_mhz * (30.0f / SI4032_CLOCK)) / 10) - 24) - (24 * hbsel)) / (1 + hbsel));
  uint8_t gen_div  =  3;  // constant - not possible to change!
  uint16_t fc = (uint16_t) (((freq_in_mhz / ((SI4032_CLOCK / gen_div) * (hbsel + 1))) - fb - 24) * 64000);

  radio_rw_register(0x75, (uint8_t) (0b01000000 | (fb & 0b11111) | ((hbsel & 1) << 5)), 1);
  radio_rw_register(0x76, (uint8_t) (((uint16_t)fc >> 8) & 0xff), 1);
  radio_rw_register(0x77, (uint8_t) ((uint16_t)fc & 0xff), 1);
}


void radio_disable_tx (void)
{
  radio_rw_register(0x07, 0x40, 1);
}


void radio_soft_reset (void)
{
  radio_rw_register(0x07, 0x80, 1);
}


void radio_enable_tx (void)
{
  radio_rw_register(0x07, 0x4B, 1); // was 0x48 ???
}


int8_t radio_read_temperature (void)
{
  uint8_t temp;
  // Read ADC Value.
  // Temp (degC) = -64 + ADC Value * 0.5
  temp = radio_rw_register(0x11, 0xff, 0);
  int16_t temp_2 = -64 + ((int16_t)temp * 5) / 10; // Convert ADC value to signed temperature value.
  radio_rw_register(0x0f, 0x80, 1); // Trigger ADC to capture another measurement.
  return (int8_t)temp_2; // Cast temperature value to int8_t and return.
}