sd_ble_gatts_hvx returns NRF_ERROR_INVALID_STATE after sending many notifications.

RE: sd_ble_gatts_hvx returns NRF_ERROR_INVALID_STATE after sending many notifications.

Kenneth — Mon, 01 Feb 2021 13:16:29 GMT

I recommend to check out chapter 36:
https://developer.apple.com/accessories/Accessory-Design-Guidelines.pdf

I am not aware of such document for Android, but if it works with iOS, it will work with Android is the general impression I have.

RE: sd_ble_gatts_hvx returns NRF_ERROR_INVALID_STATE after sending many notifications.

karanbakshi — Fri, 29 Jan 2021 06:36:37 GMT

Hi Kenneth,

After some research on devezon, I found similar problem as below.

https://devzone.nordicsemi.com/f/nordic-q-a/11837/automatically-disconnection-ios/44800#44800

So I have tried a sniffer trace and found that there is a "LL_TERMINATE_IND" about 95 seconds after the "CONNECT_REQ". This error code means "Unacceptable connection parameter". My issue was with iOS only. With android, it works well.

So with change in min and max connection interval, it is resolved now but my concern is that what min and mix connection interval should be kept in firmware to make it compatible with all kind of iOS and android devices?

Regards,

Bipin Patel

RE: sd_ble_gatts_hvx returns NRF_ERROR_INVALID_STATE after sending many notifications.

Kenneth — Wed, 27 Jan 2021 14:29:53 GMT

I can't really think of anything else no, an nRF sniffer log may be helpful. If you ignore NRF_ERROR_INVALID_STATE, does it eventually work again later?

Kenneth

RE: sd_ble_gatts_hvx returns NRF_ERROR_INVALID_STATE after sending many notifications.

karanbakshi — Wed, 27 Jan 2021 07:50:24 GMT

Thanks Kenneth for reply.

For Invalid Connection State, I have tried to check any disconnection request from device or phone app side but there is no such request occur from any side.

For On going ATT MTU exchange, I think this happened initially after connection but I am getting NRF_ERROR_INVALID_STATE after a while, nearly 1 min. Do you think ATT MTU exchange may also happened after 1 mins?

Let me know if other things I needs to check.

Regards,

Bipin Patel

RE: sd_ble_gatts_hvx returns NRF_ERROR_INVALID_STATE after sending many notifications.

Kenneth — Mon, 25 Jan 2021 15:15:17 GMT

From the documentation I can find about NRF_ERROR_INVALID_STATE:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v7.2.0/group___b_l_e___g_a_t_t_s___f_u_n_c_t_i_o_n_s.html#ga313fe43c2e93267da668572e885945db

One or more of the following is true:

Invalid Connection State
Notifications and/or indications not enabled in the CCCD
An ATT_MTU exchange is ongoing

If this happens after a while I guess the most likely reasons are:

Invalid Connection State

An example would be if sd_ble_gatts_hvx is called when disconnected, for instance after sd_ble_gap_disconnect() but before the reception of the BLE_GAP_EVT_DISCONNECTED event.

On going ATT MTU exchange

The simplest solution would be to retry until the ATT MTU exchange is finished. Another solution would be to set a flag when a BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST is received, check this flag prior to calling sd_ble_gatts_hvx and then clear the flag when the NRF_BLE_GATT_EVT_ATT_MTU_UPDATED is generated by the NRF GATT module(nrf_ble_gatt.c).