I get soft reset when MTU is bigger than 65

[Stefan]

Hello!

I am trying to increase the MTU size to get higher speeds. When I increase the MTU above 65 the application locks/software reset when doing transfer. Up to 65 it works. I have increased RAM memory for SoftDevice a lot. No difference. I check the return value of softdevice_enable(). Always zero. I have not enabled DLE.

65 sounds awfully close to 64, but it is still a bit strange value.

Any hints or tips would be appreciated

[Stefan]

Hi Sigurd,

I use SDK 12.2 (SD132).

I do not test on any particular example, I do test it on our application directly. I try to speed up transfers and currently increasing the MTU seems to be the only viable way.

I set MTU by:

#if (NRF_SD_BLE_API_VERSION == 3)
    ble_enable_params.gatt_enable_params.att_mtu = NRF_BLE_MAX_MTU_SIZE;
#endif
    // Enable BLE stack.
    ble_enable_params.gatts_enable_params.service_changed = IS_SRVC_CHANGED_CHARACT_PRESENT;
    err_code = softdevice_enable(&ble_enable_params);
    APP_ERROR_CHECK(err_code);

I hope this is the way to do it in 12.*.

I will check out the debugging post you refer to, thanks!