Per the dialog here: Re: Characteristic of variable-length write
I changed the 5th parameter as " LEGATTDB_PERM_WRITE_CMD | LEGATTDB_PERM_VARIABLE_LENGTH" then I could get the actual length information of the data.
But there is another problem.
When I send 15 bytes data, it's OK. But when I sent the 16bytes data or more, nothing happened. The write call-back doesn't fire at all.
BLE pdu packet can send 22byte or someting, but the BCM90737 hardware buffer is 16. So I think the maximum data length is up to 16 bytes. Not 15bytes.
And some sample program set 20byte as the write characteristic size. What is the correct size of the data length for one packet?
It's 20 byte.
Anyway, for different question creating new thread is recommended.