Hi,
I have built a timer triggered ADC program to read 4 different channel using sequencer 1. I am checking values in watch window in debug mode. While the ADC is measuring values properly, channels are getting swapped. Here is the code:
#include <stdint.h>
#include <stdbool.h>
#include <math.h>
#include "inc/tm4c123gh6pm.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/sysctl.h"
#include "driverlib/interrupt.h"
#include "driverlib/gpio.h"
#include "driverlib/timer.h"
#include "driverlib/adc.h"
#include "driverlib/fpu.h"
#include "driverlib/pin_map.h"
uint32_t ui32ADC0Value[4];
volatile uint32_t a,b,c,d;
int main(void)
{
//Set processor @ 80 MHz.
SysCtlClockSet(SYSCTL_SYSDIV_2_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);
//===============================================================================================
//Give clock to the peripherals:
//GPIO for testing: LED: R B G
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
//GPIO for capture interrupt
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
//ADC pins
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
//Timer for 40 kHz calc and adc trigger
SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
//ADC 0
SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
SysCtlDelay(10);
//===============================================================================================
//Peripheral configuration
//Config GPIO: LED R B G
GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);
//Config Timer0: 40 kHz
TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC); //32 bit mode
TimerLoadSet(TIMER0_BASE, TIMER_A, 2000-1); //load period
IntEnable(INT_TIMER0A); //interrupt enable
TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT); //interrupt condition: timeout
TimerControlTrigger(TIMER0_BASE, TIMER_A, true); //ADC trigger
//Configure ADC0
ADCSequenceDisable(ADC0_BASE, 1);
GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_0);
GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_1);
GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_2);
GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_3);
GPIOPinTypeADC(GPIO_PORTD_BASE, GPIO_PIN_3);
ADCSequenceConfigure(ADC0_BASE, 1, ADC_TRIGGER_TIMER, 0); //sequencer 1, proccessor trig, priority zero highest
ADCSequenceStepConfigure(ADC0_BASE, 1, 0, ADC_CTL_CH4);
ADCSequenceStepConfigure(ADC0_BASE, 1, 1, ADC_CTL_CH3);
ADCSequenceStepConfigure(ADC0_BASE, 1, 2, ADC_CTL_CH2);
ADCSequenceStepConfigure(ADC0_BASE, 1, 3, ADC_CTL_CH1|ADC_CTL_IE|ADC_CTL_END); //final step: give int, stop
IntEnable(INT_ADC0SS1);
ADCIntClear(ADC0_BASE, 1);
ADCIntEnable(ADC0_BASE, 1);
//===============================================================================================
//Enable the peripherals one by one
//Int master enable
IntMasterEnable();
//Timer0: Calc & ADC trigger
TimerEnable(TIMER0_BASE, TIMER_A);
//ADC
ADCSequenceEnable(ADC0_BASE, 1);
//===============================================================================================
while(1)
{
}
}
//===============================================================================================
void Timer0IntHandler(void)
{
TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
if(GPIOPinRead(GPIO_PORTC_BASE, GPIO_PIN_4))
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, 0);
else
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, 2);
}
//================================================================================================
void ADC0SS1IntHandler(void)
{
ADCIntClear(ADC0_BASE, 1);
ADCSequenceDataGet(ADC0_BASE, 1, ui32ADC0Value);
a = ui32ADC0Value[0];
b = ui32ADC0Value[1];
c = ui32ADC0Value[2];
d = ui32ADC0Value[3];
}
//==================================================================================================
e.g. the graph of first value ui32ADC0Value[0] is shown
There are sudden random spikes, which correspond to readings of other channels.
If all 4 steps in the sequencer are configured to read the same channel then the issue does not arise. So hardware seems fine.
Has anyone encountered similar issue?
Thank you.
-Saurabh
