strange behaviour of spi handler

[Jorge]

Hi,

I'm using the SDK11 and SD130 on a custom board which has a nrf51822. I connected via SPI to a DSP that sends and receive audio. My handler of the SPI is as it follows

/**********************************
 * @brief SPI user event handler  *
 * @param event										*
 **********************************/
 void spi_event_handler(nrf_drv_spi_evt_t const * p_event)
 {
	 nrf_gpio_pin_toggle(WAKEUP_PIN);
	 uint8_t i = 0;
	 
	 NRF_LOG_PRINTF("[MAIN : SPI] Transfered : %s\r\n", spi_tx_buf);
	 memset(spi_tx_buf, 0, spi_length);
	 NRF_LOG_PRINTF("[MAIN : SPI] Received: %s\r\n", spi_rx_buf);
	 memcpy(spi_tx_buf, spi_rx_buf, spi_length);
	 if(spi_counter < ble_length)
	 {
			while(i < spi_length)
			{
				buffer_send_ble[i+spi_counter] = spi_rx_buf[i];
				i++;
			}
			spi_counter = spi_counter + i;
	 }
	 if(spi_counter>=ble_length)	//if there is no more
	 {
		 spi_counter = 0;
			#ifdef OVERBLE
				BLE_flag = true;	
			#endif	 
	 }
		 
 }

So as you can see I'm copying the data from the spi_rx to spi_tx. and then do another spi transfer on the main. The problem is that I only have clear sound when I have the NRF_LOG_PRINTF, if I comment one or both the sound just get worse.

Is this a meant thing? does it need a delay or something? I can't understand why it only works if I have them.

Thank you for the help,

Jorge Costa

[Jorge]

It was a timing issue. The toggle of the WAKEUP_PIN was to update the sampling rate on the DSP, but it was wrongly configured there. And so only with the "delay" of the prints the sampling rate on both sides would match.

Now with that fixed I can delete the prints and the sound has good quality! Thank you all for the help