3. Exercise: Transmission in Synchronous Serial Mode

So far, the CC1200 has only been used in receive mode, either to measure the RSSI of a bit stream in synchronous serial mode or the receive a packet in FIFO mode. Now, let us experience the transmission mode. In this exercise we will transmit a bit stream from a sender to a receiver.

CC1200 will be set into synchronous serial mode. In this mode, CC1200 provides clock on one of the GPIO input lines. On the falling edge, data on the serial input line - normally on GPIO0 line - will be transferred on the media.

This task requires

• a ready BeagleBone Black equipped with the CC1200
• another BeagleBone Block equipped with the CC1200
• 4C.

• connect the first BeagleBone Black to your computer and install, execute 4C.
• open TX Synchronous Serial Mode in test window.
• export all registers to a file.
• connect the BeagleBone Black to your computer and login as superuser.
• copy the export file from 4C to the BeagleBone Black.
• import the export file into your program and initialize the registers according the values of the export file.
• Read chapter 6.9 about the RSSI of the CC1200 Users Guide and implement it.
• if the program is correctly compiled and linked start it.
• If this is the case bring 4C in “Continuous RX” mode and start the transmitter. At 4C the RSSI should increase. If switching off the transmitter, the RSSI should drop down.

• Your transmitter will insert a sync-word for better bit synchronization. Try to figure out, what sync word will be used.
• Figure out, the use of the GPIO lines (what functions have the lines).