CYW20706 : In hci_serial_gatt_service(BSG), Problem of continuous data transmission.

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JaLe_1578121
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Hi, I'm testing hci_serial_gatt_service for the BLE Serial Service.

- Unidirectional data transmission is not a problem.

  • Client_Control.exe ===> CYW20706(Peripheral) ===> LE BSG Client(Central) : OK
  • LE BSG Client(Central) ===> CYW20706(Peripheral) ===> Client_Control.exe : OK

- But, When continuous data is sent in both directions, there is a problem that data can not be transmitted or received.

  • Client_Control.exe <===> CYW20706(Peripheral) <===> LE BSG Client(Central)

<Test Environment>

  • Chipset : CYW20706
  • WICED Version : WICED-Studio-6.1
  • Example : hci_serial_gatt_service
  • Test Program : Client_Control.exe & LE BSG Client(apk)

<Test Procedure>

  1. "hci_serial_gatt_service" Build & Download
  2. RUN the Client_Control.exe
  3. Start Advertise
  4. RUN the LE BSG Client
  5. Search and Connect
  6. Continuous data transmission from Client_Control.exe to LE BSG Client.
  7. Continuous data transmission from LE BSG Client to Client_Control.exe.

How can I solve this problem.

Please, Help me.

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1 Solution
SheetalJ
Moderator
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First comment on KBA 750 replies posted 500 likes received

Hi jmlee_1578121​,

As per my understanding, you want simultaneous transmission of data over GATT.

Simultaneous data transmission using GATT profile is not possible according to spec. So I don't think you will be able to achieve Client_Control.exe <===> CYW20706(Peripheral) <===> LE BSG Client(Central) this purpose here.

Please explain more about your query to make it more clear.

View solution in original post

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5 Replies
SheetalJ
Moderator
Moderator
Moderator
First comment on KBA 750 replies posted 500 likes received

Hi jmlee_1578121​,

As per my understanding, you want simultaneous transmission of data over GATT.

Simultaneous data transmission using GATT profile is not possible according to spec. So I don't think you will be able to achieve Client_Control.exe <===> CYW20706(Peripheral) <===> LE BSG Client(Central) this purpose here.

Please explain more about your query to make it more clear.

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Hi shjl

Is it impossible to send and receive data in both directions at the same time using  Serial over GATT?

Is this not supported by the Bluetooth SPEC?

In more detail, I want to implement the following.

a. Periodically, data is sent from CYW20706 to BSG Client(Android Phone APP).

b. At the same time, data is sent from BSG Client(Android Phone APP) to CYW20706.

Hi jmlee_1578121​,

Please check Bluetooth spec section 6 BLUETOOTH APPLICATION ARCHITECTURE -> 6.4 GENERIC ATTRIBUTE PROFILE (Spec version 5.0): https://www.bluetooth.com/specifications/bluetooth-core-specification

This will give you detailed info of GATT profile.

I don't think the simultaneous transmission of data is possible. You have to send data one after another.

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Hi shjl

I can not understand your explanation.

Although I may misunderstand,

There seems to be no point in the BLUETOOTH SPEC that continuous two-way communication is not possible.

After all, does WICED's BSG Solution (BLE Serial Service) not support full_duplex?

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Hi jmlee_1578121​,

GATT server and client works on request-response manner.

This may give you an insight on the data exchange process: https://learn.adafruit.com/introduction-to-bluetooth-low-energy/gatt

We do not support full duplex transmission over GATT in WICED.