I am trying to retrieve the values from the ADC on my MSP430F5529 and send them to my computer over USB, but I am starting small. All I have right now I something that retrieves the ADC value and stores it in ADCResults, if the read value is over half of Vcc then an LED turns on.
I have pin 6.0 hooked up to a force sensor so I can see it turn off and on when I put my finger down on it or release it.
The program works perfectly when I run it in debug mode but when I try to run it outside debug mode (just powering the board from the computer after the code is downloaded to it), nothing happens when I put my finger on the force sensor.
Whats extremely odd is if i hold down reset while putting my finger on the force sensor (putting my finger down causes the LED to turn on), and release the reset button the LED stays on until I hit reset again with my finger off it, so it seems reset is causing an issue but I'm not sure how.
At first I thought reset was being pulled constantly high (or low, whatever resets the device), but that can't be true because then the program should work if I held reset down, but it doesn't!
Here is my code:
#include "driverlib.h"
volatile uint16_t ADCResults = 0;
void main(void)
{
//Stop Watchdog Timer
WDT_A_hold(WDT_A_BASE);
//P6.0 ADC option select
GPIO_setAsPeripheralModuleFunctionOutputPin(
GPIO_PORT_P6,
GPIO_PIN0
);
GPIO_setAsOutputPin(
GPIO_PORT_P1,
GPIO_PIN0
);
//Initialize the ADC12_A_A Module
/*
* Base address of ADC12_A_A Module
* Use internal ADC12_A_A bit as sample/hold signal to start conversion
* USE MODOSC 5MHZ Digital Oscillator as clock source
* Use default clock divider of 1
*/
ADC12_A_init(ADC12_A_BASE,
ADC12_A_SAMPLEHOLDSOURCE_SC,
ADC12_A_CLOCKSOURCE_ADC12OSC,
ADC12_A_CLOCKDIVIDER_1);
ADC12_A_enable(ADC12_A_BASE);
/*
* Base address of ADC12_A_A Module
* For memory buffers 0-7 sample/hold for 64 clock cycles
* For memory buffers 8-15 sample/hold for 4 clock cycles (default)
* Disable Multiple Sampling
*/
ADC12_A_setupSamplingTimer(ADC12_A_BASE,
ADC12_A_CYCLEHOLD_64_CYCLES,
ADC12_A_CYCLEHOLD_4_CYCLES,
ADC12_A_MULTIPLESAMPLESDISABLE);
//Configure Memory Buffer
/*
* Base address of the ADC12_A_A Module
* Configure memory buffer 0
* Map input A0 to memory buffer 0
* Vref+ = AVcc
* Vr- = AVss
* Memory buffer 0 is not the end of a sequence
*/
ADC12_A_configureMemoryParam param = {0};
param.memoryBufferControlIndex = ADC12_A_MEMORY_0;
param.inputSourceSelect = ADC12_A_INPUT_A0;
param.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;
param.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;
param.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;
ADC12_A_configureMemory(ADC12_A_BASE,¶m);
//Enable memory buffer 0 interrupt
ADC12_A_clearInterrupt(ADC12_A_BASE,
ADC12IFG0);
ADC12_A_enableInterrupt(ADC12_A_BASE,
ADC12IE0);
while(1)
{
//Enable/Start sampling and conversion
/*
* Base address of ADC12_A_A Module
* Start the conversion into memory buffer 0
* Use the single-channel, single-conversion mode
*/
ADC12_A_startConversion(ADC12_A_BASE,
ADC12_A_MEMORY_0,
ADC12_A_SINGLECHANNEL);
//LPM0, ADC12_A_ISR will force exit
__bis_SR_register(LPM0_bits + GIE);
//for Debugger
__no_operation();
}
}
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC12_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(ADC12_VECTOR)))
#endif
void ADC12_A_ISR(void)
{
switch(__even_in_range(ADC12IV,34))
{
case 0: break; //Vector 0: No interrupt
case 2: break; //Vector 2: ADC overflow
case 4: break; //Vector 4: ADC timing overflow
case 6: //Vector 6: ADC12IFG0
//Is Memory Buffer 0 = A0 > 0.5AVcc?
ADCResults = ADC12_A_getResults(ADC12_A_BASE,
ADC12_A_MEMORY_0);
if(ADCResults
>= 0x7ff)
{
//set P1.0
GPIO_setOutputHighOnPin(
GPIO_PORT_P1,
GPIO_PIN0
);
}
else
{
//Clear P1.0 LED off
GPIO_setOutputLowOnPin(
GPIO_PORT_P1,
GPIO_PIN0
);
}
//Exit active CPU
__bic_SR_register_on_exit(LPM0_bits);
case 8: break; //Vector 8: ADC12IFG1
case 10: break; //Vector 10: ADC12IFG2
case 12: break; //Vector 12: ADC12IFG3
case 14: break; //Vector 14: ADC12IFG4
case 16: break; //Vector 16: ADC12IFG5
case 18: break; //Vector 18: ADC12IFG6
case 20: break; //Vector 20: ADC12IFG7
case 22: break; //Vector 22: ADC12IFG8
case 24: break; //Vector 24: ADC12IFG9
case 26: break; //Vector 26: ADC12IFG10
case 28: break; //Vector 28: ADC12IFG11
case 30: break; //Vector 30: ADC12IFG12
case 32: break; //Vector 32: ADC12IFG13
case 34: break; //Vector 34: ADC12IFG14
default: break;
}
}
UPDATE
I have tried do make the same functionality not using the peripheral driver library and it seems to work perfectly outside the debugger. This leads me to believe something is wrong with Texas Instruments Peripheral Driver Library.
Here is the code that seemed to work fine outside the debugger and doens't use the Peripheral Driver Library.
#include <msp430.h>
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
ADC12CTL0 = ADC12SHT02 + ADC12ON; // Sampling time, ADC12 on
ADC12CTL1 = ADC12SHP; // Use sampling timer
ADC12IE = 0x01; // Enable interrupt
ADC12CTL0 |= ADC12ENC;
P6SEL |= 0x01; // P6.0 ADC option select
P1DIR |= 0x01; // P1.0 output
while (1)
{
ADC12CTL0 |= ADC12SC; // Start sampling/conversion
__bis_SR_register(LPM0_bits + GIE); // LPM0, ADC12_ISR will force exit
__no_operation(); // For debugger
}
}
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = ADC12_VECTOR
__interrupt void ADC12_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC12_VECTOR))) ADC12_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(ADC12IV,34))
{
case 0: break; // Vector 0: No interrupt
case 2: break; // Vector 2: ADC overflow
case 4: break; // Vector 4: ADC timing overflow
case 6: // Vector 6: ADC12IFG0
if (ADC12MEM0 >= 0x7ff) // ADC12MEM = A0 > 0.5AVcc?
P1OUT |= BIT0; // P1.0 = 1
else
P1OUT &= ~BIT0; // P1.0 = 0
__bic_SR_register_on_exit(LPM0_bits); // Exit active CPU
case 8: break; // Vector 8: ADC12IFG1
case 10: break; // Vector 10: ADC12IFG2
case 12: break; // Vector 12: ADC12IFG3
case 14: break; // Vector 14: ADC12IFG4
case 16: break; // Vector 16: ADC12IFG5
case 18: break; // Vector 18: ADC12IFG6
case 20: break; // Vector 20: ADC12IFG7
case 22: break; // Vector 22: ADC12IFG8
case 24: break; // Vector 24: ADC12IFG9
case 26: break; // Vector 26: ADC12IFG10
case 28: break; // Vector 28: ADC12IFG11
case 30: break; // Vector 30: ADC12IFG12
case 32: break; // Vector 32: ADC12IFG13
case 34: break; // Vector 34: ADC12IFG14
default: break;
}
}
Best Answer
Sometimes the reason for such behavior is that optimization settings are different in debug mode, and some variable that the compiler thinks isn't needed is then optimized right out.
The fixes for this are to add "volatile" qualifiers to such variables, or to turn optimization off (or at least turn it down).
I don't know if this is your answer (the thread becaume TL;DR), but this tidbit should certainly appear as a possible solution for the search engines.