gattc read in multi connect

[Siva Subrahmanyam]

I am using S120 Softdevice, with bunch of different type ble tags(peripherals). written a code to connect multiple tags at a time and doing a gattc read to fetch the battery level.

Each type of tag has different read handles for battery read.

I am getting invalid battery levels.

Verified with gatt tool & nrfconnect on each tag type and came to conclusion that read request are not going to specific tag. i.e after connecting to multiple tags doing a gattc read request to multiple tags are getting misplaced. I verified that i am sending appropriate read handle for sd_ble_gattc_read after connect event.

Is there issue with multi connect.

[Sigurd]

Hi,

What SDK version are you using? Make sure that sd_ble_gattc_read(...) uses both the correct connection handle and the correct attribute handle.

[Siva Subrahmanyam]

I am using nordic_sdk_7, with S120 Softdevice on PCA10001 board running ble_connectivity example program.

We are using appropriate reaad handle along with connection handle.

Here is the SetUp details: I am using beagle board as application board, PCA10001 as connectivity board. I had given a lot of debug prints to make sure that we are sending apropriate read handle.

[Sigurd]

Ok, what do you mean by "I am getting invalid battery levels." ? Are you getting garbage values? or are you getting the value from a different board that you intended?

Is the values you get consistent? or do they change significantly from each read with sd_ble_gattc_read(...)?

[Siva Subrahmanyam]

I am not getting garbage values, I am getting 2%,8% battery values. verified with nrf connect on each tag it was showing 91%.

Yes, I am getting values from different type of tag. there is cross talk happening with multi connect.

I got two type tags TagA, TagB each 15 quantity. Tag A battery read handle 0x09,Tag B battery read handle 0x12. when read request are going to other tags i am getting 2%,8% battery reads.

[Sigurd]

I am not getting garbage values, I am getting 2%,8% battery values. verified with nrf connect on each tag it was showing 91%.

• Are you using the BLE battery service for this?
• So none of the tags really have 2 %, 8% battery level?
• How are you measuring the battery level? Are you using the ADC for this?
• When does this bug happen? Only when you are reading different tags at once?