Reading RSSI of SensorTag with BTool issues

Michael Robinson93

Prodigy 145 points

Other Parts Discussed in Thread: CC2541

Hello,

I am using the BTool to communicate with a cc2541 sensorTag using the HCI_ReadRSSI command.

However all values that I receive back from my device are greater than 100 (201, 203, 214, etc).

Is there an issue with the command or do I need to carry out a conversion to receive a dB value?

Many thanks,

Tom

over 10 years ago

0 YiKai Chen over 10 years ago

Guru 735695 points

It's 2's complement.

0 Michael Robinson93 over 10 years ago in reply to YiKai Chen

Prodigy 145 points

Please expand,

So if I receive a decimal value of 212, if it is two's complement, it will be equal to 43 in decimal.

Is this i mW?

I.E. for calculating RSSI it will be equal to 10log(43mW) = -137 dBm?

Or is the 43 value the dBm RSSI, i.e. -43 dBm?

Thanks

0 YiKai Chen over 10 years ago in reply to Michael Robinson93

Guru 735695 points

The binary of decimal 212 is 11010100. You would get -44 if you convert 11010100 from 2's compliment to decimal.

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Reading RSSI of SensorTag with BTool issues