used MCLK with GPIO for external compenant clock

Question

Hi, 
 I would like to use MCK as a clock for adc CLK 4Mhz. 
 Could i enable & configure all registers without I2S or PDM peripheral activation? 
 Is there a sample code for MCLK configuration?

user113284 · Accepted Answer

Thank you for your feedback. i did it with I2S activation, without nominate LRCK,SCLK,DATA, juste MCLK. Here is the code #include #include #include #include #include #include #include static void i2s_clk_init(void); // a modifier #define I2S_MCK_PIN 15 // MCLK pin is GPIO2 #define I2S_DATA_BLOCK_WORDS 512 //How many numbers do we want. time reorded = DATA_BLOCK_WORDS / freq static uint32_t m_buffer_rx32u[I2S_DATA_BLOCK_WORDS]; static nrfx_i2s_buffers_t i2s_initial_buffers; // I2S ISR handler ISR_DIRECT_DECLARE(i2s_isr_handler) { nrfx_i2s_irq_handler(); ISR_DIRECT_PM(); // PM done after servicing interrupt for best latency return 1; // We should check if scheduling decision should be made } // I2S event handler static void i2s_data_handler(nrfx_i2s_buffers_t const *p_released, uint32_t status) { if (NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED == status) { nrfx_i2s_next_buffers_set(&i2s_initial_buffers); } } /***************************************************************************** * Function: i2s_clk_init * * Description: provide 2.1333333 MHz. reference clock to audio ADC * * Parameters: none * * Returns: nothing *****************************************************************************/ static void i2s_clk_init(void) { // the audio clock defaults to 12.288MHz, so we don't need to adjust it // configure I2S IRQ_DIRECT_CONNECT(I2S0_IRQn, 0, i2s_isr_handler, 0); i2s_initial_buffers.p_rx_buffer = m_buffer_rx32u; nrfx_i2s_config_t i2s_cfg = NRFX_I2S_DEFAULT_CONFIG(NRFX_I2S_PIN_NOT_USED, NRFX_I2S_PIN_NOT_USED, I2S_MCK_PIN, NRFX_I2S_PIN_NOT_USED, NRFX_I2S_PIN_NOT_USED); i2s_cfg.clksrc = NRF_I2S_CLKSRC_PCLK32M ; // audio clock i2s_cfg.mck_setup = NRF_I2S_MCK_32MDIV15; i2s_cfg.enable_bypass = false; // bypass division, so we get the raw audio clock nrfx_err_t err_code = nrfx_i2s_init(&i2s_cfg, i2s_data_handler); if(err_code != NRFX_SUCCESS) { printk("Error initializing I2S "); return; } } void MCLK_Start(void) { nrfx_err_t err_code; i2s_clk_init(); // start i2s err_code = nrfx_i2s_start(&i2s_initial_buffers, I2S_DATA_BLOCK_WORDS, 0); if (err_code != NRFX_SUCCESS) { printk("I2S start error "); } } void MCLK_stop(void) { // stop i2s nrfx_i2s_stop(); } juste be carful to add the necessary in CMakeLists file

used MCLK with GPIO for external compenant clock

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