Characteristic - Multiple Fields

[Anonymous]

Up until now all my custom characteristics have had a single data field, e.g. one uint8.  When using multiple data fields, how are they individually managed?  Here is my code that updates a characteristic:

void Updatecharacteristic(uint8* Data, uint16 len, uint16 attrHandle)

{

/* 'Handle' stores data parameters */

    CYBLE_GATT_HANDLE_VALUE_PAIR_T Handle;

    /* Update handle with new values */

    Handle.attrHandle = attrHandle;

    Handle.value.val = Data;

    Handle.value.len = len;

    /* Update the attribute value. This will allow

    * Client device to read the existing values over

    *  characteristic */

    CyBle_GattsWriteAttributeValue(&Handle,

    FALSE,

    &cyBle_connHandle,

    CYBLE_GATT_DB_PEER_INITIATED);

    /* Send the response to the write request received. */

    CyBle_GattsWriteRsp(cyBle_connHandle);

}

Thanks

Rich

[Anonymous]

I am guessing that all the data fields are concatenated into one data/number depending on the types.  That the fields are not individually accessible. 

Is this correct?

Rich

[Anonymous · Accepted solution]

Hi,

Whatever be the datatype used, it should be converted into uint8 types. For example if you have to send an uint16 array[ ] of 4 elements, you need to separate each word into two uint8 bytes (high end and lower end). Thus this array is converted into a uint8 array of length 8 and sent.

Regards,

- Madhu Sudhan

[Anonymous]

Thanks Madhu.  So all characteristics are just a single string of bytes and the "fields" in the gui are just there for convenience?  Multiple fields of varying data types will presented as a string of bytes and it is up to the developer to parse the bytes.  Is that correct?

Rich

[Anonymous]

Yes. If you want the data to be easier to parse, you can clarify that by having the data split into multiple characteristics, as this allows using handles to differentiate data types/usage. The data bytes themselves will always be available/read/written as uint8 byte arrays to/from the database code.