cpu.getIOUnit(IOPort.class, "P8").addPortListener(this);
IOUnit usart0 = cpu.getIOUnit("USCI B0");
if (usart0 instanceof USARTSource) {
radio = new CC2520(cpu);
radio.setGPIO(1, port1, CC2520_FIFO);
radio.setGPIO(3, port1, CC2520_CCA);
radio.setGPIO(2, port1, CC2520_FIFOP);
radio.setGPIO(4, port2, CC2520_SFD);