TWI hard faulting

[[email protected]]

Been working to get the TWI communicating to a LIS331HH and been having tons of trouble getting it functioning.

I do an init like the example

void twi_init (void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = SCL_PORT,
       .sda                = SDA_PORT,
       .frequency          = NRF_DRV_TWI_FREQ_100K,
       .interrupt_priority = APP_IRQ_PRIORITY_MID,
       .clear_bus_init     = false
    };

    err_code = nrf_drv_twi_init(&m_twi, &twi_config, twi_handler, NULL);
    APP_ERROR_CHECK(err_code);

    nrf_drv_twi_enable(&m_twi);
}

then when i try to do any tx/rx

    ret_code_t err_code;
    uint8_t twidat = 0;
    err_code = nrf_drv_twi_rx(&m_twi,0x18,&twidat,sizeof(twidat));
    APP_ERROR_CHECK(err_code);

following the code by stepping in it goes to this function and hardfaults

__STATIC_INLINE void nrf_twi_int_enable(NRF_TWI_Type * p_reg,
                                        uint32_t       mask)
{
    p_reg->INTENSET = mask;
}

thanks,

Kevin

[Jørgen Holmefjord]

Hi,

How is m_twi defined in your application?

Are you triggering the TX/RX operations from main or interrupt context?

Do you use a SoftDevice in your application? 

Which SDK version are you using?

Best regards,
Jørgen

[[email protected]]

Hi Jørgen, thank you for taking the time to look into this.

1) it's defined globally at the top of one of our .h files;

which is included at the bottom of our main includes section;

2) we've tried several methods, i'm currently down to a simple example to try to get something working and hoping to built from there-this is currently called in main after are setup;

3) S112, i think we originally copied this project from the PCA10040e S112 blinky example

4) nRF5_SDK_17.1.0_ddde560

we have a git repo if that helps.

[Jørgen Holmefjord]

[email protected] said:

2) we've tried several methods, i'm currently down to a simple example to try to get something working and hoping to built from there-this is currently called in main after are setup;

It looks to me like you in this example are calling nrf_drv_twi_rx, without first initializing the TWI driver, is that correct?

Since you have declared m_twi as static in a header file, you should not access it from multiple .c files (e.g. main.c and salt_lick_accel.c), as each file will have its own copy of the object. This means that if you initialize m_twi using a function in salt_lick_accel.c, the m_twi object in main.c will still be uninitialized.

If you can upload a .zip file of your project here, that would make it easier for us to reproduce/debug the issue.

Best regards,
Jørgen

[[email protected]]

salt_lick_firmware.zip

The code *hopefully* initializes it in twi_init() is called in main. I didn't know that static variables shouldn't be accessed by multiple files. there's probably other things being done wrong here, so we appreciate you looking at it!

[Jørgen Holmefjord]

The hardfault seems to be caused by modifications in the file "salt_lick_firmware\modules\nrfx\mdk\nrf52810_peripherals.h". Reverting this file back to the original from nRF5 SDK v17.1.0 seems to fix the issue.

Setting TWIM_COUNT to 0 will create an empty array of m_handlers in nrf_drv_twi.c, which makes the TWI interrupt handler trying to call an invalid address. The MDK files should normally not be modified, as this can cause issues like this.