htim1.Init.Period = ctc; // Count up to this value (how many 64uS ticks per symbol)

    htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;

    htim1.Init.RepetitionCounter = 0;

    HAL_TIM_Base_Init(&htim1);

    HAL_TIM_Base_Start_IT(&htim1);

    HAL_NVIC_SetPriority(TIM1_BRK_UP_TRG_COM_IRQn, 0, 0);

    HAL_NVIC_EnableIRQ(TIM1_BRK_UP_TRG_COM_IRQn);

    // TODO: Bring up TCXO sooner! Gotta let it warm up or something

    HAL_GPIO_WritePin(OSC_NOTEN, 0);

    HAL_GPIO_WritePin(TCXO_EN, 1);

    HAL_Delay(100);

    // Bring up the chip

    i2c_init();

    si5351_init(i2c_get(), SI5351_CRYSTAL_LOAD_8PF, 0);

    si5351_set_correction(0);

    //si5351_set_pll(SI5351_PLL_FIXED, SI5351_PLLA);

    //si5351_set_ms_source(SI5351_CLK0, SI5351_PLLA);

    si5351_set_freq(WSPR_DEFAULT_FREQ * 100, 0, SI5351_CLK0);

//    si5351_drive_strength(SI5351_CLK0, SI5351_DRIVE_8MA); // Set for max power if desired (8ma max)

    si5351_output_enable(SI5351_CLK0, 1);

    //si5351_pll_reset(SI5351_PLLA);

    // Make sure the other outputs of the SI5351 are disabled

    si5351_output_enable(SI5351_CLK1, 0); // Disable the clock initially

    si5351_output_enable(SI5351_CLK2, 0); // Disable the clock initially

    // disable clock powers

    si5351_set_clock_pwr(SI5351_CLK1, 0);

    si5351_set_clock_pwr(SI5351_CLK2, 0);

    // Encode message to transmit

    wspr_encode(call, loc, dbm, tx_buffer);

    // Key transmitter

    si5351_output_enable(SI5351_CLK0, 1);

    // Loop through and transmit symbols TODO: Do this from an ISR or ISR-triggered main loop function call (optimal)

    uint8_t i;

    for(i=0; i<symbol_count; i++)

    {

        uint32_t freq2 = (freq * 100) + (tx_buffer[i] * tone_spacing);

        si5351_set_freq(freq2, 0, SI5351_CLK0);