From your description, my understanding is you want to receive the parameters from the Client app on ther GATT Server (PSoC) end.
Actually, it largely depends on the method adopted on Client app. There are 2 methods of data from GATT Client to GATT Server - Write Request and Write Command. The GATT Server should handle the wirte request/command properly.
▪ Write Request: The GATT Client sends this request to the GATT Server to write an attribute value. The GATT Server responds to the GATT Client, indicating whether the value was written. A smartphone writing a value of 0x01 to the CCCD of a Battery Level characteristic to enable notifications is an example of a Write Request.
▪ Write Command: The GATT Client sends this command to the GATT Server to write an attribute value. The GATT Server does not send any response to this command. For example, the BLE Immediate Alert Service (IAS) uses a Write Command to trigger an alert (turn on an LED, ring a buzzer, drive a vibration motor, and so on) on an IAS Target device (for example, a BLE key fob) from an IAS locator (for example, a smartphone).
Let me know if I get you purpose correctly.
Thank you for you feedback.
Your explanation has been quite informative to me. This is very helpful.
I have an additional question though, What if I want to send a large file over bluetooth? Do I use the same approach but change the datatype for the required characteristic?
Lets say I will send a 3KB File from the GATT Client to the GATT Server to process. Do I use an array of uint8 of size 512? And use a buffer to write every 512bytes to an SD card?
It's less common to transmit a large amount of data from GATT Client to GATT Server, and currently there might not be proper demo to demonstrate this kind data flow.
However, you can do that using the two formats - write request / command to complete that. For the 2 actions, there should be target attribute on GATT Server side to receive the data.
I agree it is very uncommon to take this route. However, I was not able to find Object Transfer Protocol Service in the PSoC Creator 4.1. Can you shed some light on this?
Object Transfer Protocol Service looks not in the list of PSoC Creator BLE library yet.
In addition, PSoC Creator 4.1 is not the latestet version. You can get the updated v4.2/4.3 from - https://www.cypress.com/products/psoc-creator-integrated-design-environment-ide