adc clock in nrf51

[nordicbeginner]

what is minimum clock at which adc can operate in nrf51??. can anyone tell me?? how to change adc clock in nrf51??. i am using sdk11

[Sigurd]

You don't have any measurements?

[nordicbeginner]

/* Copyright (c) 2014 Nordic Semiconductor. All Rights Reserved. * * The information contained herein is property of Nordic Semiconductor ASA. * Terms and conditions of usage are described in detail in NORDIC * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT. * * Licensees are granted free, non-transferable use of the information. NO * WARRANTY of ANY KIND is provided. This heading must NOT be removed from * the file. * */

/** @file
 * @defgroup nrf_adc_example main.c
 * @{
 * @ingroup nrf_adc_example
 * @brief ADC Example Application main file.
 *
 * This file contains the source code for a sample application using ADC.
 *
 * @image html example_board_setup_a.jpg "Use board setup A for this example."
 */
 
#include "nrf.h"

#ifdef NRF51

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "nrf_adc.h"
#include "boards.h"
#include "app_uart.h"
#include "app_error.h"
#include "nrf_delay.h"

volatile int32_t adc_sample;

#define UART_TX_BUF_SIZE 256 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 1   /**< UART RX buffer size. */

#ifndef NRF_APP_PRIORITY_HIGH
#define NRF_APP_PRIORITY_HIGH 1
#endif

/**
 * @brief UART events handler.
 */
void uart_events_handler(app_uart_evt_t * p_event)
{
    switch (p_event->evt_type)
    {
        case APP_UART_COMMUNICATION_ERROR: APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:          APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        case APP_UART_TX_EMPTY:            
            break;

        default: break;
    }
}


/**
 * @brief ADC interrupt handler.
 */
void ADC_IRQHandler(void)
{
    nrf_adc_conversion_event_clean();

    adc_sample = nrf_adc_result_get();
}


/**
 * @brief UART initialization.
 */
void uart_config(void)
{
    uint32_t                     err_code;
    const app_uart_comm_params_t comm_params =
    {
        RX_PIN_NUMBER,
        TX_PIN_NUMBER,
        RTS_PIN_NUMBER,
        CTS_PIN_NUMBER,
        APP_UART_FLOW_CONTROL_DISABLED,
        false,
        UART_BAUDRATE_BAUDRATE_Baud38400
    };

    APP_UART_FIFO_INIT(&comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_events_handler,
                       APP_IRQ_PRIORITY_LOW,
                       err_code);

    APP_ERROR_CHECK(err_code);
}


/**
 * @brief ADC initialization.
 */
void adc_config(void)
{
    const nrf_adc_config_t nrf_adc_config = NRF_ADC_CONFIG_DEFAULT;

    // Initialize and configure ADC
    nrf_adc_configure( (nrf_adc_config_t *)&nrf_adc_config);
    nrf_adc_input_select(NRF_ADC_CONFIG_INPUT_2);
    nrf_adc_int_enable(ADC_INTENSET_END_Enabled << ADC_INTENSET_END_Pos);
    NVIC_SetPriority(ADC_IRQn, NRF_APP_PRIORITY_HIGH);
    NVIC_EnableIRQ(ADC_IRQn);
}


/**
 * @brief Function for main application entry.
 */
int main(void)
{
    adc_config();

    //uart_config();

    printf("\n\rADC HAL simple example\r\n");

    printf("Current sample value:\r\n");

    while (true)
    {
			  // trigger next ADC conversion
			  nrf_adc_start();
        // enter into sleep mode
        __SEV();
        __WFE();
        __WFE();
			
			  nrf_delay_ms(1000);
         float value = (float)((adc_sample*3.6)/1024);		
    int    adc_sample1;
    uint8_t b_percent;
      adc_sample1 =(int)adc_sample;		
       if(adc_sample1 > 835)
			 {
			   b_percent = 0x64;
			 }				 
			else if(adc_sample1 < 480)
			 {
			   b_percent =0x00;
				 
			 }
			 else
			 b_percent = ((adc_sample1-480)*100/355);
			//	printf("%d\r\n", (int)adc_sample); // out ADC result
		//	printf("%f\r\n", (float)value); // out ADC result
		//	printf("%d\r\n", adc_sample1); // out ADC result
			// printf("%x\r\n", b_percent);
    }
}

#endif /* NRF51 */

/** @} */

[nordicbeginner]

i use this code and then measure current and i am getting 11 mA

[Sigurd]

During the delay (nrf_delay_ms(..)) the CPU will be running and the current draw will large (several milliamps).

[nordicbeginner]

Hi I removed delay part and i get 4 ma current