Issues sending notifications when setting up the MCU as a central and peripheral.

RE: Issues sending notifications when setting up the MCU as a central and peripheral.

Vasav Shah — Thu, 03 Nov 2022 22:33:14 GMT

Hi Jared!

I looked at the connection handles, and it was the issue. I didn't realize that all events were triggered on all events. For anyone in the future, I used BLE_GAP_ROLE_CENTRAL and BLE_GAP_ROLE_PERIPH to differentiate between the types of connection events.

Vasav

RE: Issues sending notifications when setting up the MCU as a central and peripheral.

Jared — Wed, 02 Nov 2022 10:06:26 GMT

Hi,

What is the value of the connection handle when you get this error?

[quote user=""]The issue I'm facing is when I have a tablet connected to MCU1 and then MCU2 connects, the notifications being sent back from MCU2 do not work. I'm getting "NRF_ERROR_INVALID_STATE" while calling "sd_ble_gatts_hvx." However, if I have MCU1 and MCU2 connected, and then connect on the tablet, the notifications work fine.[/quote]

If I understand you correctly, it works fine if you first connect MCU1 and MCU2 and then connect MCU 1 and the tablet. But it doesn't work if you first connect MCU1 and the tablet before you connect MCU2 and MCU1?

regards

Jared

RE: Issues sending notifications when setting up the MCU as a central and peripheral.

Vasav Shah — Tue, 01 Nov 2022 16:11:48 GMT

Hi Jared,

I have ensured the device is connected and the CCCD is enabled. I still am not able to get the notification to pass through.

Vasav

RE: Issues sending notifications when setting up the MCU as a central and peripheral.

Jared — Tue, 01 Nov 2022 09:48:27 GMT

Hi,

sd_ble_gatts_hvx() returns NRF_ERROR_INVALID_STATE when

"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"

You can start with checking if the device is already in a connection when you try to send the notification and if you have already enabled notifications in the CCCD.

regards

Jared