Queued Write Service Halts when trying to write to characteristic

RE: Queued Write Service Halts when trying to write to characteristic

bjorn-spockeli — Thu, 06 Sep 2018 14:50:35 GMT

Writing less than 20bytes on the queued write characteristic is handled in this question:
https://devzone.nordicsemi.com/f/nordic-q-a/37970/write-queued-characteristic-with-less-than-20-bytes

RE: Queued Write Service Halts when trying to write to characteristic

jloliveira — Thu, 23 Aug 2018 19:33:59 GMT

Hi Bjørn,

Thank you for your reply.

Any news regarding writing less than 20bytes on the queued write characteristic?

Thank you,

João

RE: Queued Write Service Halts when trying to write to characteristic

bjorn-spockeli — Wed, 22 Aug 2018 13:07:49 GMT

Hi João,

You are right that something is not quite right qhen writing less than 20 bytes, i.e. BLE_QWRS_MAX_CHAR_LEN bytes, to the QWR characteristic. I will need to look into this by doing a sniffer trace and examine the on-air packets.

As for more thatn 510 bytes, as I stated in my previous reply the maximum size of a fixed length GATT Server Attribute( i.e. the size of a characteristic value) is restricted to BLE_GATTS_FIX_ATTR_LEN_MAX which is 510bytes. Hence this is the largest characteristic size you can set with the S132 v6.0.0 SoftDevice. So you will not be able to write more than 510 bytes to the QWR characteristic as this is the maximum size of a characteristic value.

Bjørn

RE: Queued Write Service Halts when trying to write to characteristic

jloliveira — Mon, 20 Aug 2018 11:53:33 GMT

Hi Bjørn,

Thank you for your reply.

The question is how to write data with less than 20bytes onto the same queued write characteristic, and if it would be possible to write more than 510bytes.

Thank you,

João

RE: Queued Write Service Halts when trying to write to characteristic

bjorn-spockeli — Thu, 16 Aug 2018 14:44:20 GMT

Hi Joao,

I sincerley apologize for the very late reply.

If you want to send more than 20bytes at the time then you need to increase the BLE_QWRS_MAX_CHAR_LEN.

The maximum size of a fixed length GATT Server Attribute( i.e. the size of a characteristic value) is restricted to BLE_GATTS_FIX_ATTR_LEN_MAX which is 510bytes. Hence this is the largest characteristic size you can set with the S132 v6.0.0 SoftDevice.

Best regards

Bjørn

RE: Queued Write Service Halts when trying to write to characteristic

jloliveira — Fri, 10 Aug 2018 11:25:00 GMT

Good afternoon,

Could anyone please look into the questions I made above?

Thank you,

João

RE: Queued Write Service Halts when trying to write to characteristic

jloliveira — Wed, 01 Aug 2018 16:54:26 GMT

Good afternoon,

Just discovered I was missing the nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle); line in the BLE_GAP_EVT_CONNECTED event which was causing the hanging, so now the problem is solved.

Yet, I still need to find a way to write data with <20bytes through the same characteristic. Is there any way to achieve this?

Also, I can only write a maximum of 510bytes of data with the Queued Write Service but I would need 1024bytes. How can I accomplish it?

Thank you,

João