PGA970EVM: Unable to connect DAC on physical output OUT pin13

Hi Yannick,

If you have the TEST_MUX_DAC_EN turned on, do you see the output changing when you set the DAC REG0 in the GUI?

Regards,

Hi scott,

Yes, if i change value of dac_REG0_2, then i can see the output change.

Is it possible to have the result of adc1 or adc2 or (adc1 - adc2) on the dac out pin with the gui?

Regards,

Yannick Bouchet

Hi scott,

i tested too the adc with "PGA970_FW_Release_1_5_Generic"
I compiled the project and use it with css.

First, the dac output dosen't work with my sensor, the secondary signal was good on oscillo.

After debugging, i understand that the compensation algorithm was an entry point arround the problem.
then i decided to un-use it.
Then i put in DAC_REG0 -> differrence == demod1 - demod2, and it also work, the dac send back an image of the sensor position.

i show you my modifications: (look: COMPENSATION_ALGO_DISABLE )

---------------------------------------------------------------------------------
interrupt void ADC_Handler(void)
{
SL coeffP;
ADC_Count1++;
#if(WATCH_DOG_TIMER_TESTING==1)
if(WDOG_Low_Time_Cnt1==0)
{
WDOG_Low_Time_Cnt1=ADC_Count1;
}

#endif /*#if(WATCH_DOG_TIMER_TESTING==1)*/
demod1 = (DEMOD1_DATA >> 8); //read 16bit ADC1 value
demod2 = (DEMOD2_DATA >> 8); //read 16bit ADC2 value

difference = demod1 - demod2;
sum = demod1 + demod2;

if (sum !=0)
{
FAST_DIV_NUMERATOR = difference;
FAST_DIV_DENOMINATOR = sum>>8;

FAST_DIV_CTRL = 0x01; // start division

while ((FAST_DIV_STAT&0x01) == 0x00); // wait for division to complete

ratio = FAST_DIV_QUOTIENT;
}

/* Accumulate the value of P channel */
FIR_AccadcValue[0] = ratio;
/* Accumulate the value of T channel */
FIR_AccadcValue[1] += ADC3_PTAT_DATA;

/* Update DAC with previous value */
if (FaultDiag == 0)
{
#if(COMPENSATION_ALGO_DISABLE == 1)
// add DC to place middle of the sensor position
// 14 -> because of 14 bits DAC resolution
DAC_REG0 = difference + ((SL)(1 << (14-1)));
#else // (WAVEFORM_LBB315PA_100_lvdt_00 == 1)
DAC_REG0 = DAC_Value;
#endif // (WAVEFORM_LBB315PA_100_lvdt_00 == 1)
}
else if (FaultDiag == 1)
{
DAC_REG0 = 0x0000;
}
else if (FaultDiag == 2)
{
DAC_REG0 = 0x0FFF;
}

/*
* Application specific Pcoefficient Calculation
* Dn = H + G * PADC/2^14 + N * (PADC/2^14)^2
* DAC = Dn
* Please refer compensation algorithm document.
*/
coeffP = (NtempCoeff[VarI] * FIR_AccadcValue[0]);
coeffP = (coeffP >> 14);
coeffP = coeffP + GtempCoeff[VarI];
coeffP = (coeffP * FIR_AccadcValue[0]);
coeffP = (coeffP >> 14);
coeffP = coeffP + HtempCoeff[VarI];
DAC_Value = (S2)(coeffP);

vi = ADC3_VI_DATA;
ptat = ADC3_PTAT_DATA;
coil3 = ADC3_COIL3_DATA;
}
------------------------------------------------------------------------------------------

How is the good way to disable compensation algorithm? directly in the code.
is there a reg related on the gui?
Is this problem is in relation with my précédent post?
How is the way, the good method, have you a documentation to calculate compensation coefficient depending of the application?
In the software user guide, i read the application software, but it dosen't help me.

Best regards,

Yannick Bouchet