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undefined reference twi error

Hi,

I hope you can help me. I get an error while compiling. I merge "twi sensor" example from sdk to the "ble app uart" example from sdk. So I customize the sdk_config to enable twi. In addition to that, I add all missing nRF_Drivers to make it work. While compiling, I get the following output:

1> "C:/Program Files/SEGGER/SEGGER Embedded Studio for ARM 4.50/gcc/arm-none-eabi/bin/as" --traditional-format -I../../../config -I../../../../../../components -I../../../../../../components/ble/ble_advertising -I../../../../../../components/ble/ble_dtm -I../../../../../../components/ble/ble_link_ctx_manager -I../../../../../../components/ble/ble_racp -I../../../../../../components/ble/ble_services/ble_ancs_c -I../../../../../../components/ble/ble_services/ble_ans_c -I../../../../../../components/ble/ble_services/ble_bas -I../../../../../../components/ble/ble_services/ble_bas_c -I../../../../../../components/ble/ble_services/ble_cscs -I../../../../../../components/ble/ble_services/ble_cts_c -I../../../../../../components/ble/ble_services/ble_dfu -I../../../../../../components/ble/ble_services/ble_dis -I../../../../../../components/ble/ble_services/ble_gls -I../../../../../../components/ble/ble_services/ble_hids -I../../../../../../components/ble/ble_services/ble_hrs -I../../../../../../components/ble/ble_services/ble_hrs_c -I../../../../../../components/ble/ble_services/ble_hts -I../../../../../../components/ble/ble_services/ble_ias -I../../../../../../components/ble/ble_services/ble_ias_c -I../../../../../../components/ble/ble_services/ble_lbs -I../../../../../../components/ble/ble_services/ble_lbs_c -I../../../../../../components/ble/ble_services/ble_lls -I../../../../../../components/ble/ble_services/ble_nus -I../../../../../../components/ble/ble_services/ble_nus_c -I../../../../../../components/ble/ble_services/ble_rscs -I../../../../../../components/ble/ble_services/ble_rscs_c -I../../../../../../components/ble/ble_services/ble_tps -I../../../../../../components/ble/common -I../../../../../../components/ble/nrf_ble_gatt -I../../../../../../components/ble/nrf_ble_qwr -I../../../../../../components/ble/peer_manager -I../../../../../../components/boards -I../../../../../../components/libraries/atomic -I../../../../../../components/libraries/atomic_fifo -I../../../../../../components/libraries/atomic_flags -I../../../../../../components/libraries/balloc -I../../../../../../components/libraries/bootloader/ble_dfu -I../../../../../../components/libraries/bsp -I../../../../../../components/libraries/button -I../../../../../../components/libraries/cli -I../../../../../../components/libraries/crc16 -I../../../../../../components/libraries/crc32 -I../../../../../../components/libraries/crypto -I../../../../../../components/libraries/csense -I../../../../../../components/libraries/csense_drv -I../../../../../../components/libraries/delay -I../../../../../../components/libraries/ecc -I../../../../../../components/libraries/experimental_section_vars -I../../../../../../components/libraries/experimental_task_manager -I../../../../../../components/libraries/fds -I../../../../../../components/libraries/fifo -I../../../../../../components/libraries/fstorage -I../../../../../../components/libraries/gfx -I../../../../../../components/libraries/gpiote -I../../../../../../components/libraries/hardfault -I../../../../../../components/libraries/hci -I../../../../../../components/libraries/led_softblink -I../../../../../../components/libraries/log -I../../../../../../components/libraries/log/src -I../../../../../../components/libraries/low_power_pwm -I../../../../../../components/libraries/mem_manager -I../../../../../../components/libraries/memobj -I../../../../../../components/libraries/mpu -I../../../../../../components/libraries/mutex -I../../../../../../components/libraries/pwm -I../../../../../../components/libraries/pwr_mgmt -I../../../../../../components/libraries/queue -I../../../../../../components/libraries/ringbuf -I../../../../../../components/libraries/scheduler -I../../../../../../components/libraries/sdcard -I../../../../../../components/libraries/slip -I../../../../../../components/libraries/sortlist -I../../../../../../components/libraries/spi_mngr -I../../../../../../components/libraries/stack_guard -I../../../../../../components/libraries/strerror -I../../../../../../components/libraries/svc -I../../../../../../components/libraries/timer -I../../../../../../components/libraries/twi_mngr -I../../../../../../components/libraries/twi_sensor -I../../../../../../components/libraries/uart -I../../../../../../components/libraries/usbd -I../../../../../../components/libraries/usbd/class/audio -I../../../../../../components/libraries/usbd/class/cdc -I../../../../../../components/libraries/usbd/class/cdc/acm -I../../../../../../components/libraries/usbd/class/hid -I../../../../../../components/libraries/usbd/class/hid/generic -I../../../../../../components/libraries/usbd/class/hid/kbd -I../../../../../../components/libraries/usbd/class/hid/mouse -I../../../../../../components/libraries/usbd/class/msc -I../../../../../../components/libraries/util -I../../../../../../components/nfc/ndef/conn_hand_parser -I../../../../../../components/nfc/ndef/conn_hand_parser/ac_rec_parser -I../../../../../../components/nfc/ndef/conn_hand_parser/ble_oob_advdata_parser -I../../../../../../components/nfc/ndef/conn_hand_parser/le_oob_rec_parser -I../../../../../../components/nfc/ndef/connection_handover/ac_rec -I../../../../../../components/nfc/ndef/connection_handover/ble_oob_advdata -I../../../../../../components/nfc/ndef/connection_handover/ble_pair_lib -I../../../../../../components/nfc/ndef/connection_handover/ble_pair_msg -I../../../../../../components/nfc/ndef/connection_handover/common -I../../../../../../components/nfc/ndef/connection_handover/ep_oob_rec -I../../../../../../components/nfc/ndef/connection_handover/hs_rec -I../../../../../../components/nfc/ndef/connection_handover/le_oob_rec -I../../../../../../components/nfc/ndef/generic/message -I../../../../../../components/nfc/ndef/generic/record -I../../../../../../components/nfc/ndef/launchapp -I../../../../../../components/nfc/ndef/parser/message -I../../../../../../components/nfc/ndef/parser/record -I../../../../../../components/nfc/ndef/text -I../../../../../../components/nfc/ndef/uri -I../../../../../../components/nfc/platform -I../../../../../../components/nfc/t2t_lib -I../../../../../../components/nfc/t2t_parser -I../../../../../../components/nfc/t4t_lib -I../../../../../../components/nfc/t4t_parser/apdu -I../../../../../../components/nfc/t4t_parser/cc_file -I../../../../../../components/nfc/t4t_parser/hl_detection_procedure -I../../../../../../components/nfc/t4t_parser/tlv -I../../../../../../components/softdevice/common -I../../../../../../components/softdevice/s140/headers -I../../../../../../components/softdevice/s140/headers/nrf52 -I../../../../../../components/toolchain/cmsis/include -I../../../../../../external/fprintf -I../../../../../../external/segger_rtt -I../../../../../../external/utf_converter -I../../../../../../integration/nrfx -I../../../../../../integration/nrfx/legacy -I../../../../../../modules/nrfx -I../../../../../../modules/nrfx/drivers/include -I../../../../../../modules/nrfx/hal -I../../../../../../modules/nrfx/mdk -I../config -mcpu=cortex-m4 -mlittle-endian -mfloat-abi=hard -mfpu=fpv4-sp-d16 -mthumb "C:/Users/hp/Desktop/Firmware Entwicklung/nRF5SDK160098a08e2.zip/examples/ble_peripheral/ble_app_uart/pca10100/s140/ses/Output/ble_app_uart_pca10100_s140 Debug/Obj/main.asm" -o "Output/ble_app_uart_pca10100_s140 Debug/Obj/main.o"
1> rm "C:/Users/hp/Desktop/Firmware Entwicklung/nRF5SDK160098a08e2.zip/examples/ble_peripheral/ble_app_uart/pca10100/s140/ses/Output/ble_app_uart_pca10100_s140 Debug/Obj/main.asm"
1> Output/ble_app_uart_pca10100_s140 Debug/Obj/main.o (28.06.2020 20:58:16) is newer than Output/Debug/Exe/ble_app_uart_pca10100_s140.elf (28.06.2020 20:57:32).
1> Linking ble_app_uart_pca10100_s140.elf
1> "C:/Program Files/SEGGER/SEGGER Embedded Studio for ARM 4.50/gcc/arm-none-eabi/bin/ld" -X --omagic -eReset_Handler --defsym=__vfprintf=__vfprintf_long --defsym=__vfscanf=__vfscanf_long -EL --gc-sections "-TC:/Users/hp/Desktop/Firmware Entwicklung/nRF5SDK160098a08e2.zip/examples/ble_peripheral/ble_app_uart/pca10100/s140/ses/Output/ble_app_uart_pca10100_s140 Debug/Obj/ble_app_uart_pca10100_s140.ld" -Map Output/Debug/Exe/ble_app_uart_pca10100_s140.map -u_vectors -o Output/Debug/Exe/ble_app_uart_pca10100_s140.elf --emit-relocs --start-group "@C:/Users/hp/Desktop/Firmware Entwicklung/nRF5SDK160098a08e2.zip/examples/ble_peripheral/ble_app_uart/pca10100/s140/ses/Output/ble_app_uart_pca10100_s140 Debug/Obj/ble_app_uart_pca10100_s140.ind" --end-group
1> C:/Program Files/SEGGER/SEGGER Embedded Studio for ARM 4.50/gcc/arm-none-eabi/bin/ld: Output/ble_app_uart_pca10100_s140 Debug/Obj/nrf_drv_twi.o: in function `nrf_drv_twi_init':
1> C:\Users\hp\Desktop\Firmware Entwicklung\nRF5SDK160098a08e2.zip\integration\nrfx\legacy/nrf_drv_twi.c:186: undefined reference to `nrfx_twi_init'
1> C:/Program Files/SEGGER/SEGGER Embedded Studio for ARM 4.50/gcc/arm-none-eabi/bin/ld: Output/ble_app_uart_pca10100_s140 Debug/Obj/main.o: in function `nrf_drv_twi_enable':
1> C:\Users\hp\Desktop\Firmware Entwicklung\nRF5SDK160098a08e2.zip\examples\ble_peripheral\ble_app_uart\pca10100\s140\ses/../../../../../../integration/nrfx/legacy/nrf_drv_twi.h:513: undefined reference to `nrfx_twim_enable'
1> C:/Program Files/SEGGER/SEGGER Embedded Studio for ARM 4.50/gcc/arm-none-eabi/bin/ld: Output/ble_app_uart_pca10100_s140 Debug/Obj/main.o: in function `nrf_drv_twi_tx':
1> C:\Users\hp\Desktop\Firmware Entwicklung\nRF5SDK160098a08e2.zip\examples\ble_peripheral\ble_app_uart\pca10100\s140\ses/../../../../../../integration/nrfx/legacy/nrf_drv_twi.h:544: undefined reference to `nrfx_twim_tx'
Build failed

But I don´t know what I´m making wrong.

Could you help me with that?

Thanks in advance

Parents
  • Hello,

    Which SDK are you using?
    If you are using the newer versions in which nrf_drv_* is legacy, you will notice that they are forwarding macros to the new nrfx_ drivers.
    Therefore, you will need to also add the nrfx_ drivers to your project for the TWI functionality to work. Namely, it seems you are missing nrfx_twim.c. You can see from the error codes that the problem is nrf_drv_twi_* making calls to undefined "nrfx_twim_*" functions.
    I would also recommend you that you work directly with the nrfx_ drivers, instead of using the legacy layers - this will decrease future work in which you will have to port your code to the nrfx_ drivers, since nrf_drv is already legacy.

    For future reference, it would be beneficial if you were specific when saying that you have added "all missing nRF_drivers to make it work" - which drivers have you added, and which changes have you made to sdk_config?

    Please let me know if this does not resolve your problem, or if anything regarding the nrfx_* vs. nrf_drv_* drivers should be unclear.

    Best regards,
    Karl

  • Hi,

    I´m using SDK 16.

    Namely, it seems you are missing nrfx_twim.c.

    I don´t think so. I added it in the folder "nRF_Drivers as shown in screenshot attached.

    I have added the twi drivers in the BLE Uart example, to make TWI work (the same drivers are used in TWI Sensor example of SDK):

    - nrfx_twim.c

    - nrf_drv_twi.c

    In addition to that, I customized sdk_config. In general I enabled all TWI options. Nothing special I think. I attached the sdk_config if it would help you for analyzing.

    53234.sdk_config.h

    Another thing is, that the application is compiling well in "release" build configuration, but not in "debug" configuration. But when I compile in "release", the BLE application doesn´t work.

    Because of nrfx_twim.c is already in my driver folder the problem exists furthermore. Is there something else I could try? Thanks in advance.

    Simon

  • Hello Simon,

    Are you attempting to use nrfx_twim, nrfx_twi or nrf_drv_twi?
    I would recommend that you only use the nrfx_ drivers directly, and I would therefore recommend using the TWIM module since it has easyDMA.

    From the looks of it, you are not actually enabling any TWI(M) instances in your sdk_config. Furthermore, you are enabling all the three different TWI drivers - nrf_twi, nrfx_twi, and nrfx_twim.
    In essence: only add the nrfx_twim.c source file to your project, and remember to #include its header file in your main.
    Then, you will need to setup the correct defines in sdk_config - you may not leave the enabling of the legacy layer in place, only the NRFX_TWIM_ENABLED should exist as a "TWI_ENABLED" in your sdk_config. For more information on why you can not leave a legacy " *_ENABLED " please see this ticket.
    Since the ble_uart example's UART is using instance 0, your TWIM will have to use instance 1, as per the Shared Resources documentation.

    I have merged the TWI sensor example functionality into the ble_uart peripheral example, please see the attached .zip folder.
    Unfortunately I have not had the opportunity to test this code with a TWI sensor, so I can not guarantee that it works as provided.
    Furthermore, it is worth noting that I have only make the necessary configurations and porting of functions from the TWI Sensor example - but no TWI functions is being scheduled / executed in the provided example. My intent is primarily to show you how you could go about adding an nrfx_ driver to your project.
    If any of my previous comments were unclear, please have a look at how it is done in the included example.

    Hope this is helpful, please let me know if your issue persists!

    Best regards,
    Karl


    ble_app_uart_with_twim.zip

  • Hi Karl,

    when I try to compile your example I get an error.

    Do I have to modify anything? I have attached the error message as screenshot.

    In config_sdk I see that "NRFX_TWIM_ENABLED" is 0 and "NRFX_TWIM1_ENABLED" is 0 too. how could this work? When I change this to 1, it diesn´t work nevertheless.

    How can I make it run?

    Thanks in advance

    Simon

  • Hello Simon,

    I see that I have made the example for the nRF52840 DK, instead of the nRF52833 DK - my apologies.
    The configuration will be the same in the PCA10100 project though, so you may just have a look at how it is done in the PCA10056 project and then make the same changes to the PCA10100 project.

    Best regards,
    Karl

  • Hi Karl,

    thanks for your help. Your example is working fine now. I decided to work with your example, because I just had to include my specifif sensor part - not really complicated. For the moment there aren´t special questions from working with twim and I have a project which is compiling without any errors or warnings.

    Thanks a lot!

    regards

    Simon

  • Hello Simon,

    I am happy to hear that the example I provided is working fine for you now, and that you found it useful.

    Please do not hesitate to open a new ticket if you should encounter any issues or questions in the future.

    Good luck with your development!

    Best regards,
    Karl

Reply Children
  • Hi Karl,

    unfortunaly, I´m getting a error while trying to make my sensor work with TWIM. Maybe you could help me. I think I can reach the sensor correctly, because if I change the sensor I2C adress the application doesn´t work - so I think I2C connection works fine and the sensor is reachable.

    I´m not sure, how to work with this TWIM functions. I looked at your example, but I have one or two questions:

    1.: I wrote a function ICM20948_set_mode:

    void ICM20948_set_mode(void)
    {
    
        ret_code_t err_code;
    
    
        /* Sensor en */
        uint8_t reg[2] = {0x06, 0x01};
        nrfx_twim_xfer_desc_t normal_mode_config = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, reg, sizeof(reg));
        err_code = nrfx_twim_xfer(&m_twim, &normal_mode_config, NULL);
        while (m_xfer_done == false);
    
    
            /*Select User Bank 0 */
        reg[0] = 0x7F;
        reg[1] = 0x00;
        m_xfer_done = false;
        nrfx_twim_xfer_desc_t sensor_on = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, reg, sizeof(reg));
        err_code = nrfx_twim_xfer(&m_twim, &normal_mode_config, NULL);    APP_ERROR_CHECK(err_code);
        while (m_xfer_done == false);
    
          
    
    }

    I´m not sure, when to use "m_xfer_done = false;" In the first lines it is included, in the second lines not. I copied this from your example. It is my aim, to write to two registers:

    - Enable Sensor

    - Selecting the correct User Bank / Registertable

    2.: I wrote a function "read_sensor_data":

    static void read_sensor_data()
    {
    
        ret_code_t err_code1;
    
        /* register 0 */
        uint8_t reg1 = 0x00;
        nrfx_twim_xfer_desc_t normal_mode_config = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, &reg1, 1);
    
    
    
     m_xfer_done = false;
        
        nrfx_twim_xfer_desc_t lm75b_reading = NRFX_TWIM_XFER_DESC_RX(ICM20948_ADDR, &m_sample, 1);
    
        /* Read 1 byte from the specified address  */
        ret_code_t err_code = nrfx_twim_xfer(&m_twim, &lm75b_reading, NULL);
        APP_ERROR_CHECK(err_code);
    
    
    
    }

    So I first write the correct register - the register I want to read from (0).

    Then I read 1 byte of this register.

    The register 0 is a "test-register" from the sensor (ICM20948), and the standard value stored in this register is "0xEA". So i should read this value.

    But if I watch the value from "m_sample", there I can see different values in it...I update this variable twice a second...sometimes I can see the correct value "0xEA". But not always.  Something I´m making wrong...

    In general, for I2C communiction I need to write to a register, before I can read it. Is that correct?

    I also attached my main.c, if you need this for analyzing.

    /**
     * Copyright (c) 2014 - 2019, 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
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     * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
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     * 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_uart_over_ble_main main.c
     * @{
     * @ingroup  ble_sdk_app_nus_eval
     * @brief    UART over BLE application main file.
     *
     * This file contains the source code for a sample application that uses the Nordic UART service.
     * This application uses the @ref srvlib_conn_params module.
     */
    
    
    #include <stdint.h>
    #include <string.h>
    #include "nordic_common.h"
    #include "nrf.h"
    #include "ble_hci.h"
    #include "ble_advdata.h"
    #include "ble_advertising.h"
    #include "ble_conn_params.h"
    #include "nrf_sdh.h"
    #include "nrf_sdh_soc.h"
    #include "nrf_sdh_ble.h"
    #include "nrf_ble_gatt.h"
    #include "nrf_ble_qwr.h"
    #include "app_timer.h"
    #include "ble_nus.h"
    #include "app_uart.h"
    #include "app_util_platform.h"
    #include "bsp_btn_ble.h"
    #include "nrf_pwr_mgmt.h"
    
    #if defined (UART_PRESENT)
    #include "nrf_uart.h"
    #endif
    #if defined (UARTE_PRESENT)
    #include "nrf_uarte.h"
    #endif
    
    #include "nrfx_twim.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 DEVICE_NAME                     "TRAINIO"                               /**< Name of device. Will be included in the advertising data. */
    #define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN                  /**< UUID type for the Nordic UART Service (vendor specific). */
    
    #define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */
    
    #define APP_ADV_INTERVAL                64                                          /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */
    
    #define APP_ADV_DURATION                18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */
    
    #define MIN_CONN_INTERVAL               MSEC_TO_UNITS(20, UNIT_1_25_MS)             /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
    #define MAX_CONN_INTERVAL               MSEC_TO_UNITS(75, UNIT_1_25_MS)             /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
    #define SLAVE_LATENCY                   0                                           /**< Slave latency. */
    #define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
    #define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
    #define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
    #define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */
    
    #define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */
    
    #define UART_TX_BUF_SIZE                256                                         /**< UART TX buffer size. */
    #define UART_RX_BUF_SIZE                256                                         /**< UART RX buffer size. */
    
    // TWIM SENSOR EXAMPLE MERGE START
    
    #define TWIM_INSTANCE_ID                1
    
    
    /* TWI ICM20948 Adresse. */
    #define ICM20948_ADDR    0x69
    
    /* ICM20948 Register * s. datasheet*/
    #define USER_BANK        0x7F
    #define ACCEL_X_H        0x2D
    #define ACCEL_X_L        0x2E
    
    #define b_Battery_Pin 33
    
    
    static volatile bool m_xfer_done = false;
    
    static const nrfx_twim_t m_twim = NRFX_TWIM_INSTANCE(TWIM_INSTANCE_ID);
    
    /* Buffer for samples read from sensor. */
    static uint8_t m_sample;
    
    
    // ICM20948 Daten
    uint8_t ACCEL_X_High = 0x2D;
    uint8_t ACCEL_X_Low;
    
    // TWIM SENSOR EXAMPLE MERGE STOP
    
    BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */
    NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
    NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
    BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */
    
    static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
    static uint16_t   m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - 3;            /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */
    static ble_uuid_t m_adv_uuids[]          =                                          /**< Universally unique service identifier. */
    {
        {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
    };
    
    
    /**@brief Function for assert macro callback.
     *
     * @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 analyse
     *          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] p_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 timer module.
     */
    static void timers_init(void)
    {
        ret_code_t err_code = app_timer_init();
        APP_ERROR_CHECK(err_code);
    }
    
    /**@brief Function for the GAP initialization.
     *
     * @details This function will set up all the necessary GAP (Generic Access Profile) parameters of
     *          the device. It also sets the permissions and appearance.
     */
    static void gap_params_init(void)
    {
        uint32_t                err_code;
        ble_gap_conn_params_t   gap_conn_params;
        ble_gap_conn_sec_mode_t sec_mode;
    
        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
    
        err_code = sd_ble_gap_device_name_set(&sec_mode,
                                              (const uint8_t *) DEVICE_NAME,
                                              strlen(DEVICE_NAME));
        APP_ERROR_CHECK(err_code);
    
        memset(&gap_conn_params, 0, sizeof(gap_conn_params));
    
        gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
        gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
        gap_conn_params.slave_latency     = SLAVE_LATENCY;
        gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;
    
        err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling Queued Write Module errors.
     *
     * @details A pointer to this function will be passed to each service which may need to inform the
     *          application about an error.
     *
     * @param[in]   nrf_error   Error code containing information about what went wrong.
     */
    static void nrf_qwr_error_handler(uint32_t nrf_error)
    {
        APP_ERROR_HANDLER(nrf_error);
    }
    
    
    /**@brief Function for handling the data from the Nordic UART Service.
     *
     * @details This function will process the data received from the Nordic UART BLE Service and send
     *          it to the UART module.
     *
     * @param[in] p_evt       Nordic UART Service event.
     */
    /**@snippet [Handling the data received over BLE] */
    static void nus_data_handler(ble_nus_evt_t * p_evt)
    {
    
        if (p_evt->type == BLE_NUS_EVT_RX_DATA)
        {
            uint32_t err_code;
    
            NRF_LOG_DEBUG("Received data from BLE NUS. Writing data on UART.");
            NRF_LOG_HEXDUMP_DEBUG(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);
    
            for (uint32_t i = 0; i < p_evt->params.rx_data.length; i++)
            {
                do
                {
                    err_code = app_uart_put(p_evt->params.rx_data.p_data[i]);
                    if ((err_code != NRF_SUCCESS) && (err_code != NRF_ERROR_BUSY))
                    {
                        NRF_LOG_ERROR("Failed receiving NUS message. Error 0x%x. ", err_code);
                        APP_ERROR_CHECK(err_code);
                    }
                } while (err_code == NRF_ERROR_BUSY);
            }
            if (p_evt->params.rx_data.p_data[p_evt->params.rx_data.length - 1] == '\r')
            {
                while (app_uart_put('\n') == NRF_ERROR_BUSY);
            }
        }
    
    }
    /**@snippet [Handling the data received over BLE] */
    
    
    /**@brief Function for initializing services that will be used by the application.
     */
    static void services_init(void)
    {
        uint32_t           err_code;
        ble_nus_init_t     nus_init;
        nrf_ble_qwr_init_t qwr_init = {0};
    
        // Initialize Queued Write Module.
        qwr_init.error_handler = nrf_qwr_error_handler;
    
        err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
        APP_ERROR_CHECK(err_code);
    
        // Initialize NUS.
        memset(&nus_init, 0, sizeof(nus_init));
    
        nus_init.data_handler = nus_data_handler;
    
        err_code = ble_nus_init(&m_nus, &nus_init);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling an event from the Connection Parameters Module.
     *
     * @details This function will be called for all events in the Connection Parameters Module
     *          which are passed to the application.
     *
     * @note All this function does is to disconnect. This could have been done by simply setting
     *       the disconnect_on_fail config parameter, but instead we use the event handler
     *       mechanism to demonstrate its use.
     *
     * @param[in] p_evt  Event received from the Connection Parameters Module.
     */
    static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
    {
        uint32_t err_code;
    
        if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
        {
            err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
            APP_ERROR_CHECK(err_code);
        }
    }
    
    
    /**@brief Function for handling errors from the Connection Parameters module.
     *
     * @param[in] nrf_error  Error code containing information about what went wrong.
     */
    static void conn_params_error_handler(uint32_t nrf_error)
    {
        APP_ERROR_HANDLER(nrf_error);
    }
    
    
    /**@brief Function for initializing the Connection Parameters module.
     */
    static void conn_params_init(void)
    {
        uint32_t               err_code;
        ble_conn_params_init_t cp_init;
    
        memset(&cp_init, 0, sizeof(cp_init));
    
        cp_init.p_conn_params                  = NULL;
        cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
        cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
        cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
        cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
        cp_init.disconnect_on_fail             = false;
        cp_init.evt_handler                    = on_conn_params_evt;
        cp_init.error_handler                  = conn_params_error_handler;
    
        err_code = ble_conn_params_init(&cp_init);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for putting the chip into sleep mode.
     *
     * @note This function will not return.
     */
    static void sleep_mode_enter(void)
    {
        uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);
        APP_ERROR_CHECK(err_code);
    
        // Prepare wakeup buttons.
        err_code = bsp_btn_ble_sleep_mode_prepare();
        APP_ERROR_CHECK(err_code);
    
        // Go to system-off mode (this function will not return; wakeup will cause a reset).
        err_code = sd_power_system_off();
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling advertising events.
     *
     * @details This function will be called for advertising events which are passed to the application.
     *
     * @param[in] ble_adv_evt  Advertising event.
     */
    static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
    {
        uint32_t err_code;
    
        switch (ble_adv_evt)
        {
            case BLE_ADV_EVT_FAST:
                err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
                APP_ERROR_CHECK(err_code);
                break;
            case BLE_ADV_EVT_IDLE:
                sleep_mode_enter();
                break;
            default:
                break;
        }
    }
    
    
    /**@brief Function for handling BLE events.
     *
     * @param[in]   p_ble_evt   Bluetooth stack event.
     * @param[in]   p_context   Unused.
     */
    static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
    {
        uint32_t err_code;
    
        switch (p_ble_evt->header.evt_id)
        {
            case BLE_GAP_EVT_CONNECTED:
                NRF_LOG_INFO("Connected");
                err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
                APP_ERROR_CHECK(err_code);
                m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
                err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_GAP_EVT_DISCONNECTED:
                NRF_LOG_INFO("Disconnected");
                // LED indication will be changed when advertising starts.
                m_conn_handle = BLE_CONN_HANDLE_INVALID;
                break;
    
            case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
            {
                NRF_LOG_DEBUG("PHY update request.");
                ble_gap_phys_t const phys =
                {
                    .rx_phys = BLE_GAP_PHY_AUTO,
                    .tx_phys = BLE_GAP_PHY_AUTO,
                };
                err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
                APP_ERROR_CHECK(err_code);
            } break;
    
            case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
                // Pairing not supported
                err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_GATTS_EVT_SYS_ATTR_MISSING:
                // No system attributes have been stored.
                err_code = sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0, 0);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_GATTC_EVT_TIMEOUT:
                // Disconnect on GATT Client timeout event.
                err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
                                                 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_GATTS_EVT_TIMEOUT:
                // Disconnect on GATT Server timeout event.
                err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                                 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                APP_ERROR_CHECK(err_code);
                break;
    
            default:
                // No implementation needed.
                break;
        }
    }
    
    
    /**@brief Function for the SoftDevice initialization.
     *
     * @details This function 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);
    
        // Register a handler for BLE events.
        NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
    }
    
    
    /**@brief Function for handling events from the GATT library. */
    void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
    {
        if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
        {
            m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
            NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
        }
        NRF_LOG_DEBUG("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
                      p_gatt->att_mtu_desired_central,
                      p_gatt->att_mtu_desired_periph);
    }
    
    
    /**@brief Function for initializing the GATT library. */
    void gatt_init(void)
    {
        ret_code_t err_code;
    
        err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
        APP_ERROR_CHECK(err_code);
    
        err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling events from the BSP module.
     *
     * @param[in]   event   Event generated by button press.
     */
    void bsp_event_handler(bsp_event_t event)
    {
        uint32_t err_code;
        switch (event)
        {
            case BSP_EVENT_SLEEP:
                sleep_mode_enter();
                break;
    
            case BSP_EVENT_DISCONNECT:
                err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
                break;
    
            case BSP_EVENT_WHITELIST_OFF:
                if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
                {
                    err_code = ble_advertising_restart_without_whitelist(&m_advertising);
                    if (err_code != NRF_ERROR_INVALID_STATE)
                    {
                        APP_ERROR_CHECK(err_code);
                    }
                }
                break;
    
            default:
                break;
        }
    }
    
    /**@brief   Function for handling app_uart events.
     *
     * @details This function will receive a single character from the app_uart module and append it to
     *          a string. The string will be be sent over BLE when the last character received was a
     *          'new line' '\n' (hex 0x0A) or if the string has reached the maximum data length.
     */
    /**@snippet [Handling the data received over UART] */
    void uart_event_handle(app_uart_evt_t * p_event)
    {
        static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
        static uint8_t index = 0;
        uint32_t       err_code;
    
        switch (p_event->evt_type)
        {
            case APP_UART_DATA_READY:
                UNUSED_VARIABLE(app_uart_get(&data_array[index]));
                index++;
    
                if ((data_array[index - 1] == '\n') ||
                    (data_array[index - 1] == '\r') ||
                    (index >= 10))
                {
                    if (index > 1)
                    {
                        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
                        NRF_LOG_HEXDUMP_DEBUG(data_array, index);
    
                        do
                        {
                            uint16_t length = (uint16_t)index;
                            err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
                            if ((err_code != NRF_ERROR_INVALID_STATE) &&
                                (err_code != NRF_ERROR_RESOURCES) &&
                                (err_code != NRF_ERROR_NOT_FOUND))
                            {
                                APP_ERROR_CHECK(err_code);
                            }
                        } while (err_code == NRF_ERROR_RESOURCES);
                    }
    
                    index = 0;
                }
                break;
    
            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;
    
            default:
                break;
        }
    }
    /**@snippet [Handling the data received over UART] */
    
    
    /**@brief  Function for initializing the UART module.
     */
    /**@snippet [UART Initialization] */
    static void uart_init(void)
    {
        uint32_t                     err_code;
        app_uart_comm_params_t const comm_params =
        {
            .rx_pin_no    = RX_PIN_NUMBER,
            .tx_pin_no    = TX_PIN_NUMBER,
            .rts_pin_no   = RTS_PIN_NUMBER,
            .cts_pin_no   = CTS_PIN_NUMBER,
            .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
            .use_parity   = false,
    #if defined (UART_PRESENT)
            .baud_rate    = NRF_UART_BAUDRATE_115200
    #else
            .baud_rate    = NRF_UARTE_BAUDRATE_115200
    #endif
        };
    
        APP_UART_FIFO_INIT(&comm_params,
                           UART_RX_BUF_SIZE,
                           UART_TX_BUF_SIZE,
                           uart_event_handle,
                           APP_IRQ_PRIORITY_LOWEST,
                           err_code);
        APP_ERROR_CHECK(err_code);
    }
    /**@snippet [UART Initialization] */
    
    
    /**@brief Function for initializing the Advertising functionality.
     */
    static void advertising_init(void)
    {
        uint32_t               err_code;
        ble_advertising_init_t init;
    
        memset(&init, 0, sizeof(init));
    
        init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
        init.advdata.include_appearance = false;
        init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;
        
        init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
        init.srdata.uuids_complete.p_uuids  = m_adv_uuids;
    
        init.config.ble_adv_fast_enabled  = true;
        init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
        init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;
        init.evt_handler = on_adv_evt;
    
        err_code = ble_advertising_init(&m_advertising, &init);
        APP_ERROR_CHECK(err_code);
    
        ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
    }
    
    
    /**@brief Function for initializing buttons and leds.
     *
     * @param[out] p_erase_bonds  Will be true if the clear bonding button was pressed to wake the application up.
     */
    static void buttons_leds_init(bool * p_erase_bonds)
    {
        bsp_event_t startup_event;
    
        uint32_t err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, bsp_event_handler);
        APP_ERROR_CHECK(err_code);
    
        err_code = bsp_btn_ble_init(NULL, &startup_event);
        APP_ERROR_CHECK(err_code);
    
        *p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
    }
    
    
    /**@brief Function for initializing the nrf log module.
     */
    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 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();
        }
    }
    
    
    /**@brief Function for starting advertising.
     */
    static void advertising_start(void)
    {
        uint32_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
        APP_ERROR_CHECK(err_code);
    }
    
    
    
    
    // TWIM SENSOR EXAMPLE MERGE START
    
    
    void ICM20948_set_mode(void)
    {
    
        ret_code_t err_code;
    
        /* Sensor en */
        uint8_t reg[2] = {0x06, 0x01};
        nrfx_twim_xfer_desc_t normal_mode_config = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, reg, sizeof(reg));
        err_code = nrfx_twim_xfer(&m_twim, &normal_mode_config, NULL);
        while (m_xfer_done == false);
    
    
            /*Select User Bank 0 */
        reg[0] = 0x7F;
        reg[1] = 0x00;
        m_xfer_done = false;
        nrfx_twim_xfer_desc_t sensor_on = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, reg, sizeof(reg));
        err_code = nrfx_twim_xfer(&m_twim, &normal_mode_config, NULL);    APP_ERROR_CHECK(err_code);
        while (m_xfer_done == false);
    
          
    
    }
    
    /**
     * @brief Function for handling data from temperature sensor.
     *
     * @param[in] temp          Temperature in Celsius degrees read from sensor.
     */
    __STATIC_INLINE void data_handler(uint8_t temp)
    {
        NRF_LOG_INFO("%d", temp);
    }
    
    
    /**
     * @brief TWI events handler.
     */
    void twim_handler(nrfx_twim_evt_t const * p_event, void * p_context)
    {
        switch (p_event->type)
        {
            case NRFX_TWIM_EVT_DONE:
                if (p_event->xfer_desc.type == NRFX_TWIM_XFER_RX)
                {
                    data_handler(m_sample);
                }
                m_xfer_done = true;
                break;
            default:
                break;
        }
    }
    
    /**
     * @brief UART initialization.
     */
    void twim_init (void)
    {
        ret_code_t err_code;
    
        nrfx_twim_config_t twim_lm75b_config = NRFX_TWIM_DEFAULT_CONFIG;
    
        twim_lm75b_config.scl = 13;
        twim_lm75b_config.sda = 16;
    
        err_code = nrfx_twim_init(&m_twim, &twim_lm75b_config, twim_handler, NULL);
        APP_ERROR_CHECK(err_code);
    
        nrfx_twim_enable(&m_twim);
    }
    
    /**
     * @brief Function for reading data from temperature sensor.
     */
    static void read_sensor_data()
    {
    
        ret_code_t err_code1;
    
        /* register 0 */
        uint8_t reg1 = 0x00;
        nrfx_twim_xfer_desc_t normal_mode_config = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, &reg1, 1);
    
    
    
     m_xfer_done = false;
        
        nrfx_twim_xfer_desc_t lm75b_reading = NRFX_TWIM_XFER_DESC_RX(ICM20948_ADDR, &m_sample, 1);
    
        /* Read 1 byte from the specified address  */
        ret_code_t err_code = nrfx_twim_xfer(&m_twim, &lm75b_reading, NULL);
        APP_ERROR_CHECK(err_code);
    
    
    
    }
    
    
    
    
    
    // TWIM SENSOR EXAMPLE MERGE STOP
    
    
    
    
    /**@brief Application main function.
     */
    int main(void)
    {
        bool erase_bonds;
    
        // Initialize.
        uart_init();
        log_init();
        timers_init();
        buttons_leds_init(&erase_bonds);
        power_management_init();
        ble_stack_init();
        gap_params_init();
        gatt_init();
        services_init();
        advertising_init();
        conn_params_init();
    
        twim_init();
        ICM20948_set_mode();
    
        // Start execution.
        printf("\r\nUART started.\r\n");
        NRF_LOG_INFO("Debug logging for UART over RTT started.");
        advertising_start();
    
    
    while (true)
        {
           
            do
            {
                __WFE();
            }while (m_xfer_done == false);
         
            read_sensor_data();
         
    
    
    
           
        }
       
    }
    
    
    /**
     * @}
     */
    

    Thanks in advance!

    Simon

  • Hello Simon,

    I am terribly sorry for the long delay in answering - I have been out of office for some time now, and this ticket had the "verified answer" status, which made it slip through the cracks.
    Do you still require help with this issue?

    simon1516 said:
    I think I can reach the sensor correctly, because if I change the sensor I2C adress the application doesn´t work - so I think I2C connection works fine and the sensor is reachable.

    This is not a definitive way to confirm whether your TWI communication is succeeding or not.
    If you take a look at the TWI Scanner example you can see how you may detect the device's address, and thus ensure you are reaching the sensor correctly. I.e if you flash your device with the unmodified example, it should detect your sensor and write its device address to the log. 

    simon1516 said:
    I´m not sure, when to use "m_xfer_done = false;" In the first lines it is included, in the second lines not.

    m_xfer_done should be set true during the callback for the NRFX_TWIM_EVT_DONE event. This will ensure that the previous write / read has finished before proceeding to the next. If I remember correctly the initial value of this is false, but it would indeed be better practice to set it to false before any TWI operation is initiated.

    simon1516 said:

    Then I read 1 byte of this register.

    The register 0 is a "test-register" from the sensor (ICM20948), and the standard value stored in this register is "0xEA". So i should read this value.

    But if I watch the value from "m_sample", there I can see different values in it...I update this variable twice a second...sometimes I can see the correct value "0xEA". But not always.  Something I´m making wrong...

    It seems weird that you can only see the correct value "sometimes" - what are you seeing when the value is incorrect? Is there any errors generated when this happens?

    simon1516 said:
    In general, for I2C communiction I need to write to a register, before I can read it. Is that correct?

    Yes, in TWI communication the master must initiate the read, by writing to the slave that it would like to read out the contents of a specific register.

    Again, my apologies for the late reply.

    Looking forward to resolving this issue together!

    Best regards,
    Karl

  • Hi Karl, thank you for your reply :-)

    I am terribly sorry for the long delay in answering - I have been out of office for some time now, and this ticket had the "verified answer" status, which made it slip through the cracks.
    Do you still require help with this issue?

    No problem, and yes, I would need a little bit help.

    ----------------------------------------------------------------

    This is not a definitive way to confirm whether your TWI communication is succeeding or not.
    If you take a look at the TWI Scanner example you can see how you may detect the device's address, and thus ensure you are reaching the sensor correctly. I.e if you flash your device with the unmodified example, it should detect your sensor and write its device address to the log. 

    Done. I can reach the sensor with the example.

    It seems weird that you can only see the correct value "sometimes" - what are you seeing when the value is incorrect? Is there any errors generated when this happens?

    I have analyzed this many times now - And what I can see is: It seems that the register I read increment every "read process". So I can read the correct value exactly every 64 times.Every 64 times, because the register map (user bank 0 has 64 registers; https://invensense.tdk.com/wp-content/uploads/2016/06/DS-000189-ICM-20948-v1.3.pdf chapter 7.1). And also the other values are repeating every 64 times...I would like to show you my actual function for reading from the sensor - no worry, just a few lines of code :-)

    The code is really simple:

    1. chose the correct register (write)

    2. read one byte from the sensor (read)

    static void read_sensor_data()
    {
    
            /* register "0" chose */
        uint8_t reg5 = {0x00};
        nrfx_twim_xfer_desc_t test = NRFX_TWIM_XFER_DESC_TX(ICM20948_ADDR, &reg5, sizeof(reg5));
    
        m_xfer_done = false;
        nrfx_twim_xfer_desc_t lm75b_reading = NRFX_TWIM_XFER_DESC_RX(ICM20948_ADDR, &m_sample, sizeof(m_sample));
    
        /* Read */
      ret_code_t err_code = nrfx_twim_xfer(&m_twim, &lm75b_reading, NULL);
       APP_ERROR_CHECK(err_code);
    
    
    
    }

    I think in this code is the fault, but I don´t know what I´m doing wrong. My aim is it, to read the same register every time.

    It would be great, if you can help me with that.

    Kind regards

    Simon

  • Hello Simon,

    simon1516 said:
    thank you for your reply :-)

    No problem at all, I am happy to help! :)

    simon1516 said:
    Done. I can reach the sensor with the example.

    Great, then we know the connection is working, and that the sensor is replying as expected.

    simon1516 said:
    I have analyzed this many times now - And what I can see is: It seems that the register I read increment every "read process". So I can read the correct value exactly every 64 times.Every 64 times, because the register map (user bank 0 has 64 registers; https://invensense.tdk.com/wp-content/uploads/2016/06/DS-000189-ICM-20948-v1.3.pdf chapter 7.1).

    Could you confirm for me what frequency you are using for your TWIM? - Judging by your main.c you shared some time ago, what is the value of your NRFX_TWIM_DEFAULT_CONFIG define in the sdk_config?

    simon1516 said:

    The code is really simple:

    1. chose the correct register (write)

    2. read one byte from the sensor (read)

    I am not sure I have understood you correctly, but you do nothing with your initial nrfx_twim_xfer_desc_t test struct here - you are not transferring it. with the code you share here.
    You will need to call nrfx_twim_xfer; the NRFX_TWIM_XFER_DESC_TX only creates a TX description structure.
    Especially, please see Section 6.3: Single-Byte Read Sequence in the datasheet you linked.
    Usually, you can think of even addresses as write-to addresses, and odd addresses as read-from addresses. wince the LSB of the 8-bit address determines the R/W bit.
    What does your log output when you run your program, btw?

    I highly recommend reading a this summary of the TWI protocol, to gain a better understanding of how the protocol is built.

    Looking forward to resolving this issue together!

    Best regards,
    Karl

  • Hi Karl,

    I hope you are fine.

    Could you confirm for me what frequency you are using for your TWIM? - Judging by your main.c you shared some time ago, what is the value of your NRFX_TWIM_DEFAULT_CONFIG define in the sdk_config?

    It was configured to 400k. I changed this to 100k but it doesn´t take affect. The result was the same.

    I am not sure I have understood you correctly, but you do nothing with your initial nrfx_twim_xfer_desc_t test struct here - you are not transferring it. with the code you share here.
    You will need to call nrfx_twim_xfer; the NRFX_TWIM_XFER_DESC_TX only creates a TX description structure.

    The problem is, if I add the line "err_code = nrfx_twim_xfer(&m_twim, &test, NULL);" directly behind the TX description structure the application aborts. In debug terminal I get the following messages:

    Especially, please see Section 6.3: Single-Byte Read Sequence in the datasheet you linked.
    Usually, you can think of even addresses as write-to addresses, and odd addresses as read-from addresses. wince the LSB of the 8-bit address determines the R/W bit.
    What does your log output when you run your program, btw?

    Yes, I tried to follow the insctructions from the manual:

    But in general: My understandness is, that if I call "nrfx_twim_xfer" after a "NRFX_TWIM_XFER_DESC_TX" then this "write procedure" works automatically (Start Signal, I2C Adress etc), isn´t that right?

    In addition to that, I attached my actual source code. I have just copied you example from above. The only change is, adding my sensor (ICM20948) to it instead of LM75b.

    ble_app_uart_with_twim v0.2.zip

    Thanks for help!

    Simon

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