Calling sd_ble_gatts_hvx() from within Timer ISR causes HardFault

[anealca]

I am using S132 in the Segger IDE on an nrf52832.

I am using SDK version 17.0.0_9d13099.

When I call sd_ble_gatts_hvx() from within a GPIOE ISR (externally pin triggered), at 100Hz, I can successfully send a packet.

But calling this ftn with the same parameters from within a Timer ISR, at the same rate, I get a Hard Fault.

Even sending a known packet crashes into a Hard Fault.

I have searched the Zone for similar issues but cannot seem to see a fix.

What could be the cause of this type of fault?

*
 * Send a BLE Pkt to the selected connection
 *
 * Using SDK 17.0.0_9d13099
 *
 * Note: Called on a peripheral device
 *			p_cls 		points to the local structure with a connected BLE master
 *			p_data 		points to a static uint8_t buffer with a known data string
 *			p_length 	is correct for the TX pkt
 *			conn_handle is correct
 */
send_ble_pkt(ble_cls_t * p_cls,
             uint8_t   * p_data,
             uint16_t  * p_length,
             uint16_t    conn_handle)
{
    ret_code_t                 		err_code;
    static ble_gatts_hvx_params_t   hvx_params;
    ble_cls_client_context_t * 		p_client;

    VERIFY_PARAM_NOT_NULL(p_cls);

    if ((p_cls->conn_handle == BLE_CONN_HANDLE_INVALID) 
        || (p_cls->strm_handles.value_handle == BLE_GATT_HANDLE_INVALID)
        || !p_cls->trns_enable){
        return NRF_ERROR_INVALID_STATE;
    }
    if (*p_length > BLE_CLS_MAX_DATA_LEN){
        return NRF_ERROR_INVALID_PARAM;
    }

    memset(&hvx_params, 0, sizeof(hvx_params));

    hvx_params.handle = p_cls->strm_handles.value_handle;
    hvx_params.p_data = p_data;
    hvx_params.p_len  = p_length;
    hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;

    return sd_ble_gatts_hvx(conn_handle, &hvx_params);
}

[anealca]

Somehow I cut off the "ret_code_t" return code from the included code segment.

[Vidar Berg]

Hello,

What is the interrupt priority of the timer interrupt? The CPU will raise a hardfault exception if the program makes a SD API call from an interrupt priority that is higher than the SVC interrupt itself (i.e. interrupt with pri. below 4 - lower numerical value equals higher priority).

Best regards,

Vidar

Edit: here is some general information about how the SD APIs work if you are new to the softdevice architecture: https://infocenter.nordicsemi.com/topic/sds_s140/SDS/s1xx/overview/api_overview.html and some about interrupt priorities: https://infocenter.nordicsemi.com/topic/sds_s140/SDS/s1xx/processor_avail_interrupt_latency/exception_mgmt_sd.html

[anealca]

Vicar...

Thanks for this thought...

I'm using HIGH (2) for my SAADC so I can get a 1k Ain data collection rate...

I've set the timer level to HIGH (2) as well but at 250Hz I shouldn't need it that high...

I'll lower it and see if that solves the issue.

Adrian 

[anealca]

Vidar Berg

Excellent...

Lowering the timer IRQ level to 5 solved the Hard Fault and now the code functions exactly as written...

thanks...

Problem Resolved.