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Using ADC with cc2650 Sensortag and Devpack Debugger

LimeLight
Intellectual 605 points
Other Parts Discussed in Thread: CC2650STK

Hi,

1-)I try to leran how to use adc pins on sensortag so i want to do  adjust brightness of LEDs with potentiometer. How can i do this? I viewed this example but its complicated for me. Can you show simple example about it? https://e2e.ti.com/support/wireless_connectivity/bluetooth_low_energy/f/538/p/404426/1433112#1433112

2-)Can you recommand any source about using adc functions, semaphores and hwi on CCS ? 

Thanks..

  • 0
    Guru 735455 points
    Don't understand what do you mean "using adc pins on sensortag so i want to do adjust brightness of LEDs with potentiometer"? Can you elaborate?
  • 0 in reply to YiKai Chen
    Intellectual 605 points
    I mean i want to control brightness of a led with using adc pins(DP0-DP3). The resistance is increased by potentiometer, brightness of led will decrease so i have to use adc pins ? Am i wrong?
  • 0 in reply to LimeLight
    TI__Guru 55395 points
    can you provide a diagram of your design so we can better assist you?
  • 0 in reply to LimeLight
    Guru 735455 points
    If I understand correct, you would need to use one pin as ADC to read voltage change and use another pin (maybe LED pin) to output PWM signal according to the input of ADC pin. Is my understanding correct?
  • 0 in reply to YiKai Chen
    Intellectual 605 points
    Yes you are correct Chen. Arduiono example is here maybe it provides to understand me better; 2.bp.blogspot.com/.../PotIleLedParlakligi_bb.jpg
  • 0 in reply to LimeLight
    Guru 735455 points
    I would suggest you to separate this into two parts. First, make sure you can read ADC correctly from for example DP2 on CC-DEVPACK-DEBUGGER. Second, try to implement PWM output. After you build those two successfully, you can combine them together.
  • 0 in reply to YiKai Chen
    Intellectual 605 points
    Im trying to read ADC but im confused. I have to use semaphore or hwi to read ADC? I cant understand how the mechanism works exactly?
  • 0 in reply to LimeLight
    Guru 735455 points
    Yes, it uses semaphore and hwi to read ADC in svend's sample code. When it triggers ADC sample, it would wait for semaphore until ADC sampling finish and ISR post the semaphore to complete sampling.
  • 0 in reply to YiKai Chen
    Intellectual 605 points
    Ok i got it thanks for helps.

    I have a new problem. What is that means? I can build svend's example but while debuging ,it gives this errror;

    ysbios.knl.Task: line 505: assertion failure: A_badTimeout: Can't sleep FOREVER.
    xdc.runtime.Error.raise: terminating execution
  • 0 in reply to LimeLight
    Guru 735455 points
    I use UART to dump ADC reading and don't use debug function in IDE. Maybe I can test debugging with IDE to see if I see similar issue.
  • 0 in reply to LimeLight
    Guru 735455 points
    You are welcome.
  • 0 in reply to YiKai Chen
    Intellectual 605 points 
    /* XDCtools Header files */
#include <xdc/std.h>
#include <xdc/runtime/System.h>

#include <ti/sysbios/knl/Semaphore.h>
#include <ti/sysbios/knl/Clock.h>
#include <ti/sysbios/family/arm/m3/Hwi.h>
#include <ti/sysbios/family/arm/cc26xx/Power.h>

/* BIOS Header files */
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/knl/Task.h>

/* TI-RTOS Header files */
#include <ti/drivers/PIN.h>
#include <ti/drivers/pin/PINCC26XX.h>
#include <ti/drivers/Power.h>
#include <ti/drivers/power/PowerCC26XX.h>
#include <ti/drivers/UART.h>
// #include <ti/drivers/Watchdog.h>

#include <driverlib/aux_adc.h>
#include <driverlib/aux_wuc.h>
#include <inc/hw_aux_evctl.h>

/* Board Header files */
#include "Board.h"

#define TASK_STACK_SIZE 512
#define TASK_PRI        1


char taskStack[TASK_STACK_SIZE];
Task_Struct taskStruct;


#define SAMPLECOUNT 20
#define SAMPLETYPE uint16_t
#define SAMPLESIZE sizeof(SAMPLETYPE)

#define ALS_POWER   IOID_26
#define ALS_OUTPUT  IOID_23

SAMPLETYPE adcSamples[SAMPLECOUNT];
SAMPLETYPE singleSample;

// Analog light sensor pins
const PIN_Config alsPins[] = {
		ALS_POWER       | PIN_GPIO_OUTPUT_EN | PIN_GPIO_HIGH   | PIN_PUSHPULL | PIN_DRVSTR_MAX,
		ALS_OUTPUT      | PIN_INPUT_DIS | PIN_GPIO_OUTPUT_DIS ,
		PIN_TERMINATE
};

PIN_Handle pinHandle;
PIN_State  pinState;

void taskFxn(UArg a0, UArg a1);

int main(void) {

	//Initialize pins, turn on GPIO module
	PIN_init(BoardGpioInitTable);

	//Initialize task
	Task_Params params;
	Task_Params_init(&params);
	params.priority = TASK_PRI;
	params.stackSize = TASK_STACK_SIZE;
	params.stack = taskStack;

	Task_construct(&taskStruct, taskFxn, &params, NULL);

	BIOS_start();
}

void taskFxn(UArg a0, UArg a1) {

	// Set up pins
	pinHandle = PIN_open(&pinState, alsPins);

	// Enable clock for ADC digital and analog interface (not currently enabled in driver)
	AUXWUCClockEnable(AUX_WUC_MODCLKEN0_ANAIF_M|AUX_WUC_MODCLKEN0_AUX_ADI4_M);
	// Connect AUX IO7 (DIO23) as analog input. Light sensor on SmartRF06EB
	AUXADCSelectInput(ADC_COMPB_IN_AUXIO7);


	// Set up ADC
	AUXADCEnableSync(AUXADC_REF_FIXED, AUXADC_SAMPLE_TIME_2P7_US, AUXADC_TRIGGER_MANUAL);

	// Disallow STANDBY mode while using the ADC.
	Power_setConstraint(PowerCC26XX_SB_DISALLOW);

	uint8_t currentSample = 0;

	while(currentSample < SAMPLECOUNT) {

		//Sleep 100ms in IDLE mode
		Task_sleep(100 * 1000 / Clock_tickPeriod);

		// Trigger ADC sampling
		AUXADCGenManualTrigger();
		singleSample=AUXADCReadFifo();

		adcSamples[currentSample++] = singleSample;

	}

	// Disable ADC
	AUXADCDisable();
	// Allow STANDBY mode again
	Power_releaseConstraint(PowerCC26XX_SB_DISALLOW);

	// Restore pins to values in BoardGpioTable
	PIN_close(pinHandle);
}

    I modified svend's code like this but doesnt works. Why?

    Thanks..
  • 0 in reply to LimeLight
    Guru 735455 points
    I see you remove semaphore. You might need to add a sleep in between "AUXADCGenManualTrigger()" and "singleSample=AUXADCReadFifo()" like the followings:

    AUXADCGenManualTrigger();
    Task_sleep(100 * 1000 / Clock_tickPeriod);
    singleSample=AUXADCReadFifo();
  • 0 in reply to YiKai Chen
    Intellectual 605 points

    Hi,

    I can read ADC values from potentiometer but it gives wrong value. Always it shows values that are between 0 - 3900ohm. I tried different pot.(10k and 1k) but nothing changes. If i change the AUXADC_REF_VDDS_REL to AUXADC_REF_FIXED, it shows  between 0-3100ohm . Why?  

    Here is my code 

    /* XDCtools Header files */
#include <xdc/std.h>
#include <xdc/runtime/System.h>

#include <ti/sysbios/knl/Semaphore.h>
#include <ti/sysbios/knl/Clock.h>
#include <ti/sysbios/family/arm/m3/Hwi.h>
#include <ti/sysbios/family/arm/cc26xx/Power.h>

/* BIOS Header files */
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/knl/Task.h>

/* TI-RTOS Header files */
#include <ti/drivers/PIN.h>
#include <ti/drivers/pin/PINCC26XX.h>
#include <ti/drivers/Power.h>
#include <ti/drivers/power/PowerCC26XX.h>
#include <ti/drivers/UART.h>

#include <driverlib/aux_adc.h>
#include <driverlib/aux_wuc.h>
#include <inc/hw_aux_evctl.h>

/* Board Header files */
#include "Board.h"

#define TASK_STACK_SIZE 512
#define TASK_PRI        1

char taskStack[TASK_STACK_SIZE];
Task_Struct taskStruct;

Semaphore_Struct sem;
Semaphore_Handle hSem;

#define SAMPLETYPE uint16_t

#define ALS_POWER   IOID_26
#define ALS_OUTPUT  IOID_27

SAMPLETYPE singleSample;
// Analog light sensor pins
const PIN_Config alsPins[] = {
		ALS_POWER       | PIN_GPIO_OUTPUT_EN | PIN_GPIO_HIGH   | PIN_PUSHPULL | PIN_DRVSTR_MAX,
		ALS_OUTPUT      | PIN_INPUT_DIS | PIN_GPIO_OUTPUT_DIS ,
		PIN_TERMINATE
};

PIN_Handle pinHandle;
PIN_State  pinState;

//UART_Handle uHandle;

void taskFxn(UArg a0, UArg a1);

int main(void) {

	//Initialize pins, turn on GPIO module
	PIN_init(BoardGpioInitTable);

	//Initialize task
	Task_Params params;
	Task_Params_init(&params);
	params.priority = TASK_PRI;
	params.stackSize = TASK_STACK_SIZE;
	params.stack = taskStack;

	Task_construct(&taskStruct, taskFxn, &params, NULL);

	BIOS_start();
}

void taskFxn(UArg a0, UArg a1) {


	Semaphore_Params sParams;
	Semaphore_Params_init(&sParams);
	sParams.mode = Semaphore_Mode_BINARY;

	Semaphore_construct(&sem, 0, &sParams);
	hSem = Semaphore_handle(&sem);
	// Set up pins
	pinHandle = PIN_open(&pinState, alsPins);

	// Enable clock for ADC digital and analog interface (not currently enabled in driver)
	AUXWUCClockEnable(AUX_WUC_MODCLKEN0_ANAIF_M|AUX_WUC_MODCLKEN0_AUX_ADI4_M);
	// Connect AUX IO3 (DIO27) as analog input. Light sensor on SmartRF06EB
	AUXADCSelectInput(ADC_COMPB_IN_AUXIO3);


	// Set up ADC
	AUXADCEnableSync(AUXADC_REF_FIXED, AUXADC_SAMPLE_TIME_2P7_US, AUXADC_TRIGGER_MANUAL);

	// Disallow STANDBY mode while using the ADC.
	Power_setConstraint(PowerCC26XX_SB_DISALLOW);

	while(1) {

		//Sleep 100ms in IDLE mode
		Task_sleep(100 * 1000 / Clock_tickPeriod);
		// Trigger ADC sampling
		AUXADCGenManualTrigger();
		Semaphore_pend(hSem, 100 );
		singleSample=AUXADCReadFifo();

	}
}

    Thanks..

  • 0 in reply to LimeLight
    Guru 735455 points
    What is the input voltage range on your ADC input pin?
  • 0 in reply to YiKai Chen
    Intellectual 605 points

    I have cc2650stk so the input voltage range 0-3V on ADC pins.

  • 0 in reply to LimeLight
    Guru 735455 points
    Do you measure voltage on ADC input pin when you tried different pot (10k and 1k)?
  • 0 in reply to YiKai Chen
    Intellectual 605 points

    I measured the voltage and it seems no problem. It is between 0-3.3V . but i cant understand the reading value(singleSample) in my previous post ? it should show 10000 if i connect 10k pot. Am i wrong?

  • 0 in reply to LimeLight
    Guru 735455 points
    If you use AUXADC_REF_FIXED as ADC reference, it is 4.3V at ADC full scale which means you will get 4095 in ADC reading when you input 4.3V to ADC input pin. However, the max allowable pin input of CC26xx can't exceed 3.6V so you won't get full scale 4095 when you use it.
  • 0 in reply to YiKai Chen
    Intellectual 605 points
    Ok i got it.
    Thank you so much.
  • 0 in reply to LimeLight
    Guru 735455 points
    You are welcome.
  • 0 in reply to YiKai Chen
    Intellectual 305 points

    would you be able to share the adc code for the sensor tag?

    thank you,

    alejandro

  • 0 in reply to user4264345
    Guru 735455 points
    You can refer to svendbt's example code in e2e.ti.com/.../2008968