BLE-TxPower spec to DBM

Question

The eddystone protocol defines the TxPower to follow the specification https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.characteristic.tx_power_level.xml&u=org.bluetooth.characteristic.tx_power_level.xml

But how do I convert a value of 0xDF to dbm using that range?

Also, I see no relation on 0x12 being +18 and 0xEE being -18.

Answer 1

There is a simple relation called Two's complement

0xDF = -33dbm

Hope it helps.

UPDATE: https://www.mathsisfun.com/binary-decimal-hexadecimal-flash.html