Minimizing the power draw using System OFF and RAM retention

Question

Hi everyone, I'm having an issue with the power draw of my application (SDK 15.0.0, SD 132 v6, Sparkfun nRF52832 Breakout). The application does roughly the following: it sleeps until it receives an GPIO interrupt (there are two different GPIOs which can wake up the application), does some (non connectable) advertising and resumes sleeping. According to the data sheet of the nRF52832 0.7 µA are possible with full RAM retention and in system state System OFF. The power draw of my application exceeds this number (around ten times higher), however I'm not utilising the System OFF mode yet (currently using only the nrf_pwr_mgmt_run() function). I did some research and discovered the sd_power_off() function. When I add the sd_power_off() function to my code, the system "freezes" / 'hangs" and draws about 10mA. I did take a look at the example "ble_app_pwr_profiling" but it is rather complex - has anyone created / found a simpler solution (do some advertising, go to System OFF with RAM retention, wake up to an GPIO interrupt, repeat) yet? How can I differentiate the two different GPIO interrupt sources when using them to wake up? (I want to count the times my application has woken up to sources 1 and 2) Best, 
 lhochstetter

Håkon Alseth · Accepted Answer

Hi, I integrated the previous example into ble_app_beacon (quick and dirty, my apologies), here's the main file and linker file (SDK v15.2): ble_app_beacon_gcc_nrf52.ld Fullscreen main.c Download /** * Copyright (c) 2014 - 2018, Nordic Semiconductor ASA * * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * 2. Redistributions in binary form, except as embedded into a Nordic * Semiconductor ASA integrated circuit in a product or a software update for * such product, must reproduce the above copyright notice, this list of * conditions and the following disclaimer in the documentation and/or other * materials provided with the distribution. * * 3. Neither the name of Nordic Semiconductor ASA nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * 4. This software, with or without modification, must only be used with a * Nordic Semiconductor ASA integrated circuit. * * 5. Any software provided in binary form under this license must not be reverse * engineered, decompiled, modified and/or disassembled. * * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ /** @file * * @defgroup ble_sdk_app_beacon_main main.c * @{ * @ingroup ble_sdk_app_beacon * @brief Beacon Transmitter Sample Application main file. * * This file contains the source code for an Beacon transmitter sample application. */ #include #include #include "nordic_common.h" #include "bsp.h" #include "nrf_soc.h" #include "nrf_sdh.h" #include "nrf_sdh_ble.h" #include "ble_advdata.h" #include "app_timer.h" #include "nrf_pwr_mgmt.h" #include "nrf_log.h" #include "nrf_log_ctrl.h" #include "nrf_log_default_backends.h" #define APP_BLE_CONN_CFG_TAG 1 /**< A tag identifying the SoftDevice BLE configuration. */ #define NON_CONNECTABLE_ADV_INTERVAL MSEC_TO_UNITS(100, UNIT_0_625_MS) /**< The advertising interval for non-connectable advertisement (100 ms). This value can vary between 100ms to 10.24s). */ #define APP_BEACON_INFO_LENGTH 0x17 /**< Total length of information advertised by the Beacon. */ #define APP_ADV_DATA_LENGTH 0x15 /**< Length of manufacturer specific data in the advertisement. */ #define APP_DEVICE_TYPE 0x02 /**< 0x02 refers to Beacon. */ #define APP_MEASURED_RSSI 0xC3 /**< The Beacon's measured RSSI at 1 meter distance in dBm. */ #define APP_COMPANY_IDENTIFIER 0x0059 /**< Company identifier for Nordic Semiconductor ASA. as per www.bluetooth.org. */ #define APP_MAJOR_VALUE 0x01, 0x02 /**< Major value used to identify Beacons. */ #define APP_MINOR_VALUE 0x03, 0x04 /**< Minor value used to identify Beacons. */ #define APP_BEACON_UUID 0x01, 0x12, 0x23, 0x34, \ 0x45, 0x56, 0x67, 0x78, \ 0x89, 0x9a, 0xab, 0xbc, \ 0xcd, 0xde, 0xef, 0xf0 /**< Proprietary UUID for Beacon. */ #define DEAD_BEEF 0xDEADBEEF /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */ #if defined(USE_UICR_FOR_MAJ_MIN_VALUES) #define MAJ_VAL_OFFSET_IN_BEACON_INFO 18 /**< Position of the MSB of the Major Value in m_beacon_info array. */ #define UICR_ADDRESS 0x10001080 /**< Address of the UICR register used by this example. The major and minor versions to be encoded into the advertising data will be picked up from this location. */ #endif static ble_gap_adv_params_t m_adv_params; /**< Parameters to be passed to the stack when starting advertising. */ static uint8_t m_adv_handle = BLE_GAP_ADV_SET_HANDLE_NOT_SET; /**< Advertising handle used to identify an advertising set. */ static uint8_t m_enc_advdata[BLE_GAP_ADV_SET_DATA_SIZE_MAX]; /**< Buffer for storing an encoded advertising set. */ /**@brief Struct that contains pointers to the encoded advertising data. */ static ble_gap_adv_data_t m_adv_data = { .adv_data = { .p_data = m_enc_advdata, .len = BLE_GAP_ADV_SET_DATA_SIZE_MAX }, .scan_rsp_data = { .p_data = NULL, .len = 0 } }; static uint8_t m_beacon_info[APP_BEACON_INFO_LENGTH] = /**< Information advertised by the Beacon. */ { APP_DEVICE_TYPE, // Manufacturer specific information. Specifies the device type in this // implementation. APP_ADV_DATA_LENGTH, // Manufacturer specific information. Specifies the length of the // manufacturer specific data in this implementation. APP_BEACON_UUID, // 128 bit UUID value. APP_MAJOR_VALUE, // Major arbitrary value that can be used to distinguish between Beacons. APP_MINOR_VALUE, // Minor arbitrary value that can be used to distinguish between Beacons. APP_MEASURED_RSSI // Manufacturer specific information. The Beacon's measured TX power in // this implementation. }; /**@brief Callback function for asserts in the SoftDevice. * * @details This function will be called in case of an assert in the SoftDevice. * * @warning This handler is an example only and does not fit a final product. You need to analyze * how your product is supposed to react in case of Assert. * @warning On assert from the SoftDevice, the system can only recover on reset. * * @param[in] line_num Line number of the failing ASSERT call. * @param[in] file_name File name of the failing ASSERT call. */ void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name) { app_error_handler(DEAD_BEEF, line_num, p_file_name); } /**@brief Function for initializing the Advertising functionality. * * @details Encodes the required advertising data and passes it to the stack. * Also builds a structure to be passed to the stack when starting advertising. */ static void advertising_init(void) { uint32_t err_code; ble_advdata_t advdata; uint8_t flags = BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED; ble_advdata_manuf_data_t manuf_specific_data; manuf_specific_data.company_identifier = APP_COMPANY_IDENTIFIER; #if defined(USE_UICR_FOR_MAJ_MIN_VALUES) // If USE_UICR_FOR_MAJ_MIN_VALUES is defined, the major and minor values will be read from the // UICR instead of using the default values. The major and minor values obtained from the UICR // are encoded into advertising data in big endian order (MSB First). // To set the UICR used by this example to a desired value, write to the address 0x10001080 // using the nrfjprog tool. The command to be used is as follows. // nrfjprog --snr --memwr 0x10001080 --val // For example, for a major value and minor value of 0xabcd and 0x0102 respectively, the // the following command should be used. // nrfjprog --snr --memwr 0x10001080 --val 0xabcd0102 uint16_t major_value = ((*(uint32_t *)UICR_ADDRESS) & 0xFFFF0000) >> 16; uint16_t minor_value = ((*(uint32_t *)UICR_ADDRESS) & 0x0000FFFF); uint8_t index = MAJ_VAL_OFFSET_IN_BEACON_INFO; m_beacon_info[index++] = MSB_16(major_value); m_beacon_info[index++] = LSB_16(major_value); m_beacon_info[index++] = MSB_16(minor_value); m_beacon_info[index++] = LSB_16(minor_value); #endif manuf_specific_data.data.p_data = (uint8_t *) m_beacon_info; manuf_specific_data.data.size = APP_BEACON_INFO_LENGTH; // Build and set advertising data. memset(&advdata, 0, sizeof(advdata)); advdata.name_type = BLE_ADVDATA_NO_NAME; advdata.flags = flags; advdata.p_manuf_specific_data = &manuf_specific_data; // Initialize advertising parameters (used when starting advertising). memset(&m_adv_params, 0, sizeof(m_adv_params)); m_adv_params.properties.type = BLE_GAP_ADV_TYPE_NONCONNECTABLE_NONSCANNABLE_UNDIRECTED; m_adv_params.p_peer_addr = NULL; // Undirected advertisement. m_adv_params.filter_policy = BLE_GAP_ADV_FP_ANY; m_adv_params.interval = NON_CONNECTABLE_ADV_INTERVAL; m_adv_params.duration = 0; // Never time out. err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_data.len); APP_ERROR_CHECK(err_code); err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, &m_adv_params); APP_ERROR_CHECK(err_code); } /**@brief Function for starting advertising. */ static void advertising_start(void) { ret_code_t err_code; err_code = sd_ble_gap_adv_start(m_adv_handle, APP_BLE_CONN_CFG_TAG); APP_ERROR_CHECK(err_code); err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING); APP_ERROR_CHECK(err_code); } /**@brief Function for initializing the BLE stack. * * @details Initializes the SoftDevice and the BLE event interrupt. */ static void ble_stack_init(void) { ret_code_t err_code; err_code = nrf_sdh_enable_request(); APP_ERROR_CHECK(err_code); // Configure the BLE stack using the default settings. // Fetch the start address of the application RAM. uint32_t ram_start = 0; err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start); APP_ERROR_CHECK(err_code); // Enable BLE stack. err_code = nrf_sdh_ble_enable(&ram_start); APP_ERROR_CHECK(err_code); } /**@brief Function for initializing logging. */ static void log_init(void) { ret_code_t err_code = NRF_LOG_INIT(NULL); APP_ERROR_CHECK(err_code); NRF_LOG_DEFAULT_BACKENDS_INIT(); } /**@brief Function for initializing LEDs. */ static void leds_init(void) { ret_code_t err_code = bsp_init(BSP_INIT_LEDS, NULL); APP_ERROR_CHECK(err_code); } /**@brief Function for initializing timers. */ static void timers_init(void) { ret_code_t err_code = app_timer_init(); APP_ERROR_CHECK(err_code); } /**@brief Function for initializing power management. */ static void power_management_init(void) { ret_code_t err_code; err_code = nrf_pwr_mgmt_init(); APP_ERROR_CHECK(err_code); } /**@brief Function for handling the idle state (main loop). * * @details If there is no pending log operation, then sleep until next the next event occurs. */ static void idle_state_handle(void) { if (NRF_LOG_PROCESS() == false) { nrf_pwr_mgmt_run(); } } #include "nrf_delay.h" uint32_t test __attribute__((section(".no_init"))) __attribute__((used)); /** * @brief Function for application main entry. */ int main(void) { // Initialize. log_init(); timers_init(); leds_init(); power_management_init(); /*for (int i = 0; i < 8; i++) NRF_POWER->RAM[i].POWER = 0xFFFFFFFF; */ ble_stack_init(); advertising_init(); sd_power_ram_power_set(7, (POWER_RAM_POWER_S1RETENTION_On << POWER_RAM_POWER_S1RETENTION_Pos)); nrf_gpio_cfg_sense_input(13, NRF_GPIO_PIN_PULLUP,NRF_GPIO_PIN_SENSE_LOW); if (test > 0) { uint8_t led_state = test % 4; nrf_gpio_pin_toggle(BSP_LED_0 + led_state); nrf_delay_us(100*1000); } test++; sd_power_system_off(); // Start execution. NRF_LOG_INFO("Beacon example started."); advertising_start(); // Enter main loop. for (;; ) { idle_state_handle(); } } /** * @} */ I didn't have any problems running this code, it loops through the LEDs like it should. Could you try this and see if that works? Kind regards, Håkon

Minimizing the power draw using System OFF and RAM retention

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