Lab 1 I/O, timers, interrupts on the eZ430-RF2500 Thomas Watteyne EE290Q – Spring

2 MSP430 “Heart” of the eZ430- RF2500 – 16-bit 16MHz RISC – 32kB ROM, 1kB RAM – 2 Timers, USCI, 10-bit ADCs Debug capabilities using JTAG Low Power Operation

3 CC2500 Any frequency on the GHz band – Not compliant Wake-on-radio support – Preamble sampling in hardware 47 configuration registers – Switch Tx/Rx/idle – TXBUF, RXBUF – Tx power and frequency Follows a state machine SmartRF Studio

4 Interconnection 4 Chip Select Clock SPI interface interrupts

5 eZ430-RF LEDs pushbutton CC2500 chip antenna 26MHz crystal for radio extension ports MSP430 USB programmer: Power Debug (JTAG) Interface (serial)

6 Extension Pins P1: GND P2: VCC_EXT P3: P2.0I/O, ACLK, OA010 P4: P2.1I/O, Timer_A3.INCLK, SMCLK, OA0O P5: P2.2I/O, Timer_A3.CCI0B, Timer_A3.TA0, OA P6: P2.3I/O, Timer_A3.CCI1B, Timer_A3.TA1, OA P7: P2.4I/O, Timer_A3.TA2, OA P8: P4.3I/O, Timer_B3.CCI0B, Timer_B3.TB0, OA P9: P4.4I/O, Timer_B3.CCI1B, Timer_B3.TB1, OA P10: P4.5I/O, Timer_B3.TB2, OA P11: P4.6I/O, OA P12: GND P13: GDO0I/O from the CC2500 (configurable) P14: GDO2I/O from the CC2500 (configurable) P15: P3.2I/O, UC1SOMI P16: P3.3I/O, UC1CLK P17: P3.0I/O P18: P3.1I/O, UC1SIMO

7 IAR Kickstart project file navigator compile open files

8 Talking with your mote over “USB” Use Windows Device Manager to idenfify the COM port the eZ430-RF2500 is on Use PuTTY to connect to that port

9 Operations on binary data A = 0b ~A = 0b A |= 0b => A=0b A &=~0b => A=0b A ^= 0b => A=0b A A=0b A>>2 => A=0b

10 I/O port registers P1DIR: direction, 0=in, 1=out P1OUT: set output P1IN: read input

11 A steady LED led_steady Disable watchdog timer P1.0 and P1.1 as output P1.0=1 and P1.1=1 Continue executing #include "io430.h" #include "in430.h" int main( void ) { WDTCTL = WDTPW + WDTHOLD; P1DIR |= 0x03; P1OUT |= 0x03; while(1); }

12 Active Waiting Loop led_loop #include "io430.h" #include "in430.h" int main( void ) { WDTCTL = WDTPW + WDTHOLD; int i; P1DIR |= 0x03; while (1) { P1OUT ^= 0x03; for (i=0;i<10000;i++) { __no_operation(); } P1.0 and P1.1 as output Change Led state (aka toggle)

13 Interrupt Interrupt only when both – General interrupt enabled in status register – Specific interrupt enabled in specific register Interrupt Service Routine written as: #pragma vector=TIMERA0_VECTOR ISR sometimes needs to clear an interrupt flag in a specific register

14 Button-Driven Toggle Through Interrupts led_button #include "io430.h" #include "in430.h" int main( void ) { WDTCTL = WDTPW + WDTHOLD; P1DIR |= 0x03; P1DIR &= ~0x04; P1REN |= 0x04; P1IE |= 0x04; __bis_SR_register(GIE); while(1); } #pragma vector=PORT1_VECTOR __interrupt void Port_1 (void) { P1IFG &= ~0x04; P1OUT ^= 0x03; } P1.2 as input enable resistor (for button) enable interrupt for P1.2 globally enable interrupts (do this last) Executed when interrupt from P1 Actual function name has no importance Clear interrupt flag (mandatory) Toggle LEDs

15 Timer A timer is a counter which – Counts in a certain way (up, down, continuous) – At every clock tick Can be used in two ways: – Triggers interrupts when reaching a given value (compare mode) or – Records its timer value on other interrupts (capture mode)

16 Timer-Driven Toggle Through Timer Interrupts led_timer #include "io430.h" #include "in430.h" int main( void ) { WDTCTL = WDTPW + WDTHOLD; P1DIR |= 0x03; TACCTL0 = CCIE; TACCR0 = 1000; TACTL = TASSEL_1 + MC_1; __bis_SR_register(GIE+LPM3_bits); } #pragma vector=TIMERA0_VECTOR __interrupt void Timer_A (void) { P1OUT ^= 0x03; } Timer_A interrupt enable Capture Compare to 1000 Count following ACLK Count in up mode interrupt Globally enable interrupt low power mode, waiting for interrupts Executed at each Timer_A interrupt