f_write/f_close cause BLE disconnect

[snowfield]

Hardware: nrf52832

SDK: 16.0.0 with FreeRtos, 

Softdevice: S132 7.0

I set configMAX_PRIORITIES to 5 and modified nrf_sdh_freertos_init to set BLE task priority to 4.

My sd card maintain task priority is set to 2.

For BLE NUS service:

#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 time-out (4 seconds). */

The NUS service and SD card function works fine when test them separately. But if Operate SD card during NUS connection, I got disconnect with reason:0x8

I have tried to enlarge INTERVAL to 120ms/175ms, also tried to change SLAVE_LATENCY to 4. Problem still exist.

I searched internet and NRF Dev Zone, found some similar question, but none of them can resolve my problem. So I have to raise a new question here. 

 

[Simonr]

Hi

Yes, you're right. I mixed up the priorities. I'm really sorry about that, but it's been some time since I have looked at FreeRTOS. And I guess that rules out that the radio is interrupted by the SD card tasks due to priorities. One thing that's worth mentioning. The default SPI settings use standard drive for the SCK and MOSI pins, so it might be worth checking if these need to be set to high drive. Something like the configuration below should do the trick:

    nrf_gpio_cfg(SCK_PIN,
                 NRF_GPIO_PIN_DIR_OUTPUT,
                 NRF_GPIO_PIN_INPUT_DISCONNECT,
                 NRF_GPIO_PIN_NOPULL,
                 NRF_GPIO_PIN_H0H1,       // Require High Drive low/high level
                 NRF_GPIO_PIN_NOSENSE);

Best regards,

Simon

[snowfield]

Dear Simonr:

     Thank you very much for mention about SPI pin setting. I will check it. And does this pin setting can affect BLE connection?

Simonr said:

And I guess that rules out that the radio is interrupted by the SD card tasks due to priorities

 And for "SD card task" , do you mean my own task (which conduct sd card operation) or there is another system level tasks to handle SD card? For my own task, I have already checked. It's priority is lower than BLE task. 

Is there any demo code for using SD card with BLE connection together successfully?