Line 56 in Illustration 12 in the ISR resets BIT3 . Why?
| | This resets the SW1 individual interrupt |
| | This toggles the CPU interrupt enable |
| | This clears the transmit registers |
Line 42 in Illustration 12 enables Port 2 Bit 3 (Switch 1) to trigger an interrupt. What other instruction is needed to allow CPU to actually be interrupted?
Line 38 in Illustration 12, how does the instruction enable the pull-up resistor for Switch 1?
| | The output bit drives the resistor to an open line |
| | The output bit isolates the resistor |
| | The output bit drives the resistor to GND |
| | The output bit drives the resistor to V+ |
Lines 24-43 in Illustration 12 would be what if Arduino style was used?
1. Single Sentence: Blink the LED with an Interrupt created by pressing a Butto 2. 3. 5. P2.3 Push button SW1 so button is BIT3 on Port 2 6. All of these operations are 8 bit (byte) writes P3DIR &BIT /BIT3 off, dic is input 8. P3RENBIT/BIT3 on, Enable internal pull-up register 9. P3OUTBIT3 10. // BIT3 on, set gutbit to pull-up 11 P3IES -BIT: BIT3 on, trigger edge rise/fall 12. P3IFG& BITE/BITB gftdleac interrupt flag 13. P3IE-BIT// BIT3 on, set interrupt enable 14. 15. #include
16. 17 18. P1.O Red LED 20. 21. 22. int main(void) 23 24. WDTCTL WDTPW+WDTHOLD: I/Stop watchdog timer 26. /Disable the GPIO power-on default high-impedance mode 27. I/to activate previously configured port settings 28. PMSCTLO & LOCKLPM5Woff 29 30. /set LED output bit 31. P1DIR-BITO;// on, Set P1.0 to output direction 32. / start with LED off 33. P10UT & BITO;// P1.0 off (LED OFF 34. 35. /P2.3 input switch (all writes are 8 bits) 36. P2DIR&-BIT3I set P2.3 as input bit (input default power-up) 37. P20UT |-BITE. // BIT3 on, set 9wbitto pull-up 38. P2REN |; BITa_// BIT3 0n. Enable internal pull up register 39. 40. P2IES -BIT// One is Falling edge 41. 42. P2IE BITBIT3 on, P2.3 interrupt enabled 43. P2IFG &"BIT3-// BIT3 off, P2.3 IFG cleared 45. /LPM4- shut down-0.49uA-OFF Section 6.3 SLASES9B 46. is SR resister LPM4_bits GIE)I/ LPM4 with interrupts enabled 50. 51. //Port 2 interrupt service routine 52. #pragma vector=PORT2 VECTOR 3 interrupt void Port_2 void) 54. 55. P1OUTA BITO; // P10 toggle lxg) 56. P2IFG &BIT3;/ P2.3 IFG off (cleared) 57. 58. // P21ES . BIT3:// toggle (Sc) the interrupt edge. 59. /the interrupt vector will be called 60. I/when P2.3 goes from Hitelew as well as LautaHieh 61, 1 1. Single Sentence: Blink the LED with an Interrupt created by pressing a Butto 2. 3. 5. P2.3 Push button SW1 so button is BIT3 on Port 2 6. All of these operations are 8 bit (byte) writes P3DIR &BIT /BIT3 off, dic is input 8. P3RENBIT/BIT3 on, Enable internal pull-up register 9. P3OUTBIT3 10. // BIT3 on, set gutbit to pull-up 11 P3IES -BIT: BIT3 on, trigger edge rise/fall 12. P3IFG& BITE/BITB gftdleac interrupt flag 13. P3IE-BIT// BIT3 on, set interrupt enable 14. 15. #include 16. 17 18. P1.O Red LED 20. 21. 22. int main(void) 23 24. WDTCTL WDTPW+WDTHOLD: I/Stop watchdog timer 26. /Disable the GPIO power-on default high-impedance mode 27. I/to activate previously configured port settings 28. PMSCTLO & LOCKLPM5Woff 29 30. /set LED output bit 31. P1DIR-BITO;// on, Set P1.0 to output direction 32. / start with LED off 33. P10UT & BITO;// P1.0 off (LED OFF 34. 35. /P2.3 input switch (all writes are 8 bits) 36. P2DIR&-BIT3I set P2.3 as input bit (input default power-up) 37. P20UT |-BITE. // BIT3 on, set 9wbitto pull-up 38. P2REN |; BITa_// BIT3 0n. Enable internal pull up register 39. 40. P2IES -BIT// One is Falling edge 41. 42. P2IE BITBIT3 on, P2.3 interrupt enabled 43. P2IFG &"BIT3-// BIT3 off, P2.3 IFG cleared 45. /LPM4- shut down-0.49uA-OFF Section 6.3 SLASES9B 46. is SR resister LPM4_bits GIE)I/ LPM4 with interrupts enabled 50. 51. //Port 2 interrupt service routine 52. #pragma vector=PORT2 VECTOR 3 interrupt void Port_2 void) 54. 55. P1OUTA BITO; // P10 toggle lxg) 56. P2IFG &BIT3;/ P2.3 IFG off (cleared) 57. 58. // P21ES . BIT3:// toggle (Sc) the interrupt edge. 59. /the interrupt vector will be called 60. I/when P2.3 goes from Hitelew as well as LautaHieh 61, 1
