CCS/TM4C1230H6PM: analog comparator 0

Gunter Heuer

Prodigy 100 points

Part Number: TM4C1230H6PM
Other Parts Discussed in Thread: EK-TM4C123GXL

Tool/software: Code Composer Studio

Hi all,

could you pls have a short look at my analog comparator 0 configuration?

It does not work.

Short:

- int ref on input + (internal)

- analog value between 0...3,3V on negative input (PC7)

- comp output on PF0

and here is my code snippet:

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/timer.h"
#include "driverlib/comp.h"

void init ()
{
uint32_t g_ui32SysClock; // System clock rate in Hz.

SysCtlClockSet (SYSCTL_SYSDIV_2_5 | SYSCTL_USE_PLL | SYSCTL_XTAL_16MHZ | SYSCTL_OSC_MAIN);

g_ui32SysClock = SysCtlClockGet ();

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOG); // Enable the GPIO ports
GPIOPinTypeGPIOOutput(GPIO_PORTG_BASE, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3); // Enable the GPIO pins for the LEDs (PN0 & PN1)

IntMasterEnable(); // Enable processor interrupts

SysCtlPeripheralEnable(SYSCTL_PERIPH_COMP0); // Enable Comparator 0

while(!SysCtlPeripheralReady(SYSCTL_PERIPH_COMP0)) // Wait for the COMP module to be ready
{
}
ComparatorRefSet(COMP_BASE, COMP_REF_0_275V); // Configure the internal voltage reference

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC); // Enable Port C
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF); // Enable Port F

GPIOPinConfigure(GPIO_PF0_C0O);
//GPIOPinConfigure(GPIO_PC7_C0-);

GPIOPinTypeComparator(GPIO_PORTC_BASE, GPIO_PIN_7); // Comparator Input
GPIOPinTypeComparatorOutput(GPIO_PORTF_BASE, GPIO_PIN_0); // Comparator Output
ComparatorConfigure(COMP_BASE, 0, (COMP_TRIG_NONE | COMP_INT_BOTH | COMP_ASRCP_REF | COMP_OUTPUT_NORMAL)); // Configure comparator 0

ComparatorValueGet(COMP_BASE, 0);

}

over 6 years ago

0 Bob Crosby over 6 years ago

TI__Guru 72500 points

I can look at it when I get back in the office on Monday. I have an example that works for the TM4C129, but of course the pins are different. It might help.
...
    //
    // Enable the COMP module.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_COMP0);
    //
    // Wait for the COMP module to be ready.
    //
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_COMP0))
    {
    }
    //
    // Configure the internal voltage reference.
    //
    ComparatorRefSet(COMP_BASE, COMP_REF_1_65V);
    //
    // Configure comparator 2.
    //
    ComparatorConfigure(COMP_BASE, 2,
    					(COMP_TRIG_NONE | COMP_ASRCP_REF | COMP_OUTPUT_NORMAL));

    //
    // Enable and wait for the port to be ready for access
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD); // For C2o
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOP); // For C2-
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPION))
    {
    }
    
    // Configure the GPIO port for the LED operation.
    GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, (USER_LED1|USER_LED2));

    // Configure the GPIO port for the comparator 2 output
    GPIOPinTypeComparatorOutput(GPIO_PORTD_BASE, GPIO_PIN_2); // PD2 is C2o
    GPIOPinConfigure(GPIO_PD2_C2O);
    GPIOPinTypeComparator(GPIO_PORTP_BASE, GPIO_PIN_1);		  // PP1 is C2-

    //
    // Loop Forever
    //
    while(1)
    {
        // Read the comparator output value.
        //
        if(ComparatorValueGet(COMP_BASE, 2) == true)
        {
        	leds = USER_LED1|USER_LED2; // blink both if input is low
        }
        else
        {
        	leds = USER_LED1;        	// blink one if input is high
        }
        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTN_BASE, (USER_LED1|USER_LED2), leds);

        //
        // Delay for a bit
        //
        SysCtlDelay(ui32SysClock/6);

        //
        // Turn off the LED
        //
        GPIOPinWrite(GPIO_PORTN_BASE, (USER_LED1|USER_LED2), 0);

        //
        // Delay for a bit
        //
        SysCtlDelay(ui32SysClock/6);
    }
}

0 Bob Crosby over 6 years ago

TI__Guru 72500 points

Here is some code that works on the EK-TM4C123GXL launchpad.

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/timer.h"
#include "driverlib/comp.h"

#define RED   GPIO_PIN_1
#define BLUE  GPIO_PIN_2
#define GREEN GPIO_PIN_3

void main()
{
    uint32_t g_ui32SysClock; // System clock rate in Hz.

    SysCtlClockSet (SYSCTL_SYSDIV_2_5 | SYSCTL_USE_PLL | SYSCTL_XTAL_16MHZ | SYSCTL_OSC_MAIN);

    g_ui32SysClock = SysCtlClockGet ();



    IntMasterEnable(); // Enable processor interrupts

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC); // Enable Port C
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF); // Enable Port F
    SysCtlPeripheralEnable(SYSCTL_PERIPH_COMP0); // Enable Comparator 0
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_COMP0)) // Wait for the COMP module to be ready
    {
    }

    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, RED | BLUE | GREEN); // Enable the GPIO pins for the LEDs (PF1-red, PF2-blue, PF3-green)

    ComparatorRefSet(COMP_BASE, COMP_REF_0_275V); // Configure the internal voltage reference
    GPIOPinConfigure(GPIO_PF0_C0O);
    GPIOPinTypeComparator(GPIO_PORTC_BASE, GPIO_PIN_7); // Comparator Input
    GPIOPinTypeComparatorOutput(GPIO_PORTF_BASE, GPIO_PIN_0); // Comparator Output

    ComparatorConfigure(COMP_BASE, 0, (COMP_TRIG_NONE | COMP_INT_BOTH | COMP_ASRCP_REF | COMP_OUTPUT_NORMAL)); // Configure comparator 0

    while(1)
    {
        if(ComparatorValueGet(COMP_BASE, 0) == true)
        {
            GPIOPinWrite(GPIO_PORTF_BASE,  RED | BLUE | GREEN, GREEN); // < 0.275V
        }
        else
        {
            GPIOPinWrite(GPIO_PORTF_BASE,  RED | BLUE | GREEN, RED); // > 0.275V
        }

    }
}

0 Gunter Heuer over 6 years ago in reply to Bob Crosby

Prodigy 100 points

Hi Bob,

thanks for the reply.

I was out for a business trip - will check immediately.

best regards Gunter

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CCS/TM4C1230H6PM: analog comparator 0