Exercise: Scan the channel and packet reception

So far, we are able to change the frequency, and we can measure the RSSI within the preamble bits. In the next step, the aim is to scan multiple channels. If a RSSI is detected, we will receive the packet. Otherwise we continue scanning.

This task requires

• a ready BeagleBone Black equipped with the CC1200 operating at a symbol rate of 1.2 kBaude.
• one TI Development Kit for the CC1200.
• Smart RF Studio sending packets with a symbol rate of 1.4 kBaude and a preamble count of 6 Bytes.

• the programming is done by extending the source files from the previous lesson Exercise: Changing the frequency.
• Extend your program by a function that measures the RSSI prior to packet reception. A packet should only be received, if a valid RSSI from the sende is detected. What means a valid RSSI ?
• Don't forger to disable preamble recognition at the receiver.
• For testing, start your program.
• Use SmartRF Studio to transmit packets at the RF frequency (do not forget to change the symbol rate and preamble count in SmartRF Studio).
• Your program should recognize a valid RSSI and start receiving packets.
• Now, change RF to a frequency the receiver is not using. Stopping and restarting the transmitter ist not necessary.
• At the receiver, the BeagleBone Black, you should now measure no valid RSSI and therefore no packet will be received.
• Now, change the frequency of SmartRF Studio back to your selected frequency.
• Now, you should be able to receive the packets again.