4.2 4.3. continuous tx/rx

Running the code

• Start from the code used in 4.2. Simple Tx/Rx .
• Replace line P1IFG&= ~0x04; by P1IFG |= 0x04; . This means that once you push the button, the board will start sending an infinite number of messages. This is because you force the interrupt flag to remain active, i.e. when your code leave the Interrupt Service Routine, it immediately re-enters because, according to the interrupt flag, there is still and interrupt pending.
• Reprogram both boards, switch them on, and push one button.

Energy consumption

• You may wish to command out lines P1OUT ^= 0x02; and P1OUT ^= 0x01; so that your LEDs remain off not to measure their energy consumption;
• Use the oscilloscope to measure the energy consumption;
• Make sure you obtain results which are close to the following figures.

Impact of transmission power

We want to measure the impact of the transmission power on the current consumption of the board. Therefore:

• if not there yet, add the following line at the beginning of your file: #include "radios/family1/mrfi_spi.h"
• right after line MRFI_Init(); , add mrfiSpiWriteReg(PATABLE,0xFF); . This programs the PATABLE register of the CC2500, which is responsible for the transmission power of the radio. You can put any value between 0x00 and 0xFF; , which is then mapped to a transmission power as shown in the next table.
• Use your oscilloscope to visualize the maximum energy consumed. Repeat this for different values of PATABLE . Check that you have results close to the ones presented in the next figure.