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Write to WriteWithoutResponse Characteristic | Cypress Semiconductor

Write to WriteWithoutResponse Characteristic

Summary: 2 Replies, Latest post by AlexSneedMiller on 15 Nov 2016 08:51 AM PST
Verified Answers: 0
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AlexSneedMiller's picture
17 posts

I have a custom BLE profile with a characteristic that has the WriteWithoutReponse box checked in the BLE component:


In my callback I was able to write code to handle a Write (with response) request.

I was surprised that this worked because I thought that the profile I had set up in the BLE component would have prevented this from happening. I was able to verify that I was able to Write (with response) to the device using a generic BLE app.

Is this supposed to happen? Does this mean that I can overwrite the configuration in the component in the schematic through the code? Is something else going on here?


Thank you!

Anjana Muralidharan's picture
Cypress Employee
131 posts


I am not sure how you have done the write operation. Any value can be written in to the GATT by locally (by same device itself) also using the same API CyBle_GattsWriteAttributeValue ().

When you will use write and write without response, you will get two separate events in the BLE  call back stack event handler:

CYBLE_EVT_GATTS_WRITE_REQ: if using 'write' (write with response)

CYBLE_EVT_GATTS_WRITE_CMD_REQ: if using 'write without response'

On getting the above events (depending upon which option has enabled),  call the CyBle_GattsWriteAttributeValue() API.



AlexSneedMiller's picture
17 posts

I did the write operation from my phone using the LightBlue Explorer App from my iPhone.

I have been calling CyBle_GattsWriteAttributeValue() in order to update the GATT database and that seems to work well. 

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