Excessive read delays

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DaGa_4378306
Level 4
Level 4
10 replies posted 5 replies posted 5 questions asked

Hi,

I'm debugging an excessive delay in BTLE GATT server read packets, and write-response packets with PSOC4 BLE Module.   Here is the setup:

PSOC4 with a Gatt server (100ms connection interval).

Raspberry Pi 4 - using gatttool to issue the char-read-hnd command.

The problem if I read using the gatttool - I can see up to 800 ms of latency between the read command, and the response packet.   Is there anything in the PSOC GATT configuration that can create such long delays?  I'm not sure if it's the gatttool latency on the Pi, or the response time from the CYBLE-214015 module I'm using?

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4 Replies
SudheeshK
Moderator
Moderator
Moderator
250 sign-ins First question asked 750 replies posted

Hello,

None of the PSoC Creator configuration options will cause read delay from our BLE module. Did you test with any other BLE client devices? Are you observing the same delay using all of the client devices?

Thanks and Regards,

Sudheesh

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AlanH_86
Employee
Employee
100 replies posted 50 replies posted 25 solutions authored

Ill bet money that this is a problem with the PI side of this connection.

How did you measure the read time?  Is that a feature of GATT Tool?

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Thanks --  I've tried two methods:

  • first is using BluePy wrapper to connect to the device -- I see the long delays.
  • Directly calling bluez gatttool using a PIPE, and I still see approximately the same delays

Both delays are measured with time.time().

Are there any other clients for the Raspberry Pi that I can use to communicate with the device?  I'm working on a Python STEM library.  I haven't found many examples of directly programming the bluez library?

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Just a quick update, after lots of playing around, I switch the

pygatt.py -- I got much better latency out of the system (more like 100ms) for a write/notify.