EE290Q Homework 1
Due Tuesday 2/2, 5pm, 512 Cory
2) Take a look at the Chipcon cc2430 datasheet. The 2420 is the most common radio chip in use in wireless sensor networks today, and the 2430 is a 2420 with an 8051 microprocessor included.
a. Looking at tables 4 and 5, what is QRX0, the charge consumed in order to go from power mode 2 to the first bit of RX? What about QTX0 ? Assume power mode 0 is the same as “Active”. Use the currents for “MCU Active and RX Mode” and “MCU Active and TX Mode, 0dBm”
b. What is the charge per bit consumed during RX? TX? What is the energy per bit consumed during RX, TX (use the voltage specified above table 4).
c. How many instructions can you execute on the processor for the same amount of charge that you burn in sending or receiving a single bit? Byte? 128 byte packet? Assume that you get one instruction per cycle, hence 32 million instructions per second at 32MHz.
d. How many bytes of data can you send with this chip with the energy stored in a single AA lithium battery (assume 2,400mAh in the battery).
e. If you send and receive one 128 byte packet per minute, and (magically) spend all of the rest of your time in power mode 2, how long with the AA lithium battery last?
f. Looking at table 45, estimate the current required to transmit at 1mW, 0.1mW, 0.01mW. What is the overhead current of this transmitter? What is the efficiency of the power amplifier?