An Autonomous Wireless Sensor Node Based on Hybrid RF Solar Energy Harvesting

Table 2

Commands available within the node.

Byte	Description of command instructions
0 × F0	Sample the temperature of the node
0 × F1^1	Show the temperature on a test point
0 × F2^1	Turn on the FRAM power supply; make the FRAM sleep
0 × F3^1	Turn off the FRAM power supply
0 × F4^1	Turn on the comparator power supply
0 × F5^1	Turn off the comparator power supply
0 × F6^1	Show the command on a test point
0 × F7^1	Reset the temperature in the node to 25°C
0 × F8	Send the node temperature via the TX module
0 × FB	Carry out sanity check of FRAM and TX modules (verify device IDs)
0 × Dn^2	Store the temperature in FRAM address n
0 × Cn^2	Retrieve the temperature in FRAM address n
0 × 3n^1,2	Set the high nibble of the temperature byte in RAM with n
0 × 4n^1,2	Set the low nibble of the temperature byte in RAM with n

¹These commands are used for debugging purposes. ²For these commands, n is a variable, ranging from 0 × 0 to 0 × F.