Other Parts Discussed in Thread: MSP430F5529
I am using the MSP430F5529-exp launchpad and code composer V6 to create some code.
I want to use P1.4 as an interrupt and I thought I would start with one of the examples from Slac300i. The example is MSP430F55XX_P1_03.
I loaded the code into code composer and ran it. It compiled and I was able to enter debug mode but nothing happened. The LED does not do anything. So I added a printf functionality to the the code to see what is happening.
The end result shows the interrupt is not recognizing an hi to low edge trigger. I am repeatable grounding the pin to create an hi-lo edge.
Here is the code I am using:
//******************************************************************************
// MSP430TC0701 Demo - Software Port Interrupt Service on P1.4 from LPM4 - modified by adding printf functionality
//
// Description: A Lo/Hi transition on P1.4 will trigger P1ISR the first time.
// On hitting the P1ISR, device exits LPM4 mode and executes section of code in
// main() which includes toggling an LED and the P1.4IES bit which switches between
// Lo/Hi and Hi/Lo trigger transitions to alternatively enter the P1ISR.
// ACLK = n/a, MCLK = SMCLK = default DCO
//
// MSP430F552x
// -----------------
// /|\| XIN|-
// | | |
// --|RST XOUT|-
// /|\ | |
// --o--|P1.4 P1.0|-->LED
// \|/
//
// Bhargavi Nisarga
// Texas Instruments Inc.
// April 2009
// Built IAR Embedded Workbench Version: 4.11A
//******************************************************************************
#include <msp430.h>
#include <MSP430F5529.h>
#include <stdio.h>
#include <string.h>
#define UART_PRINTF
#ifdef UART_PRINTF
int fputc(int _c, register FILE *_fp);
int fputs(const char *_ptr, register FILE *_fp);
#endif
int main(void)
{
#ifdef UART_PRINTF
// initialize USCI module
P4SEL |= BIT4 + BIT5; // P4.4,5 = USCI_A1 TXD/RXD
UCA1CTL1 |= UCSWRST; // **Put state machine in reset**
UCA1CTL1 |= UCSSEL__ACLK; // AMCLK
UCA1BR0 = 3; // 32,768kHz 1200 (see User's Guide), original example used 27, set to 3 for 9600
UCA1BR1 = 0; // 32,768kHz 1200, original example used 0, set to 3 for 9600
UCA1MCTL = UCBRS_3; // 32,768kHz 1200
UCA1CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
#endif
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
P1DIR |= BIT0; // Set P1.0 to output direction
P1OUT &= ~BIT0;
P1REN |= BIT4; // Enable P1.4 internal resistance
P1OUT |= BIT4; // Set P1.4 as pull-Up resistance
P1IES &= ~BIT4; // P1.4 Lo/Hi edge
P1IFG &= ~BIT4; // P1.4 IFG cleared
P1IE |= BIT4; // P1.4 interrupt enabled
printf("P1.4 interrupt example....Hello World!\r\n");
while(1)
{
printf("enter while loop.");
__bis_SR_register(LPM4_bits + GIE); // Enter LPM4 w/interrupt
__no_operation(); // For debugger
printf("about to toggle LED.");
P1OUT ^= BIT0; // P1.0 = toggle
P1IES ^= BIT4; // Toggle between H-L and L-H transition triggers
P1IE |= BIT4; // Enable port interrupt
}
}
// Port 1 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(PORT1_VECTOR))) Port_1 (void)
#else
#error Compiler not supported!
#endif
{
P1IFG &= ~BIT4; // Clear P1.4 IFG
P1IE &= ~ BIT4; // Clear P1.4 IE
printf("p1.4 was triggered!\r\n");
__bic_SR_register_on_exit(LPM4_bits); // Exit LPM4
}
#ifdef UART_PRINTF
int fputc(int _c, register FILE *_fp)
{
while(!(UCA1IFG&UCTXIFG));
UCA1TXBUF = (unsigned char) _c;
return((unsigned char)_c);
}
int fputs(const char *_ptr, register FILE *_fp)
{
unsigned int i, len;
len = strlen(_ptr);
for(i=0 ; i<len ; i++)
{
while(!(UCA1IFG&UCTXIFG));
UCA1TXBUF = (unsigned char) _ptr[i];
}
return len;
}
#endif
----------
The output of the printf on the serial port is the following:
P1.4 interrupt example....Hello World!
enter while loop.
--------
So, why does this example not work ? It should be a clean piece of code since it is an example. :)
How do I troubleshoot an interrupt issue?
Repeatedly grounding the P1.4 pin to create an edge transition is not working.
Also, when I put 3.3V on P1.4 the system crashes.
Any help would be great.
Chris
