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AD5755-1 : change its output voltage/current value doesn't work

Question asked by xview on Feb 1, 2018
Latest reply on Mar 13, 2018 by DragosB

Dear Sir/Madam,

 

I used non-OS example code of AD5755-1 from ADI web site, and try to evaluate the performance of the AD5755-1 board. It not always gets the correct result as expected and it cannot be changed output value after first configured. The evaluated code is as follows,

 

//========================================================

AD5755_Init();

AD5755_SetRegisterValue(AD5755_DREG_WR_GAIN, AD5755_DAC_A, 0xFFFF);

AD5755_SetRegisterValue(AD5755_DREG_WR_OFFSET, AD5755_DAC_A, 0x8000);

AD5755_SetRegisterValue(AD5755_DREG_WR_CLR_CODE, AD5755_DAC_A, 0x0000);

AD5755_SetChannelRange(AD5755_DAC_A, AD5755_R_0_5_V);

AD5755_SetVoltage(AD5755_DAC_A, 1.25);

// The above codes sometimes run as expected, but sometimes run unpredictable.

 

// The following codes do not effect the output value of the AD5755-1 board

float fVal=0.0;
while(1)
{
   AD5755_SetVoltage(AD5755_DAC_A, fVal);

   TIME_DelayMs(3000);
   fVal += 0.2;

   if (fVal >4.0)
   fVal=0.0;
}

//========================================================

 

In the circuit of AD5755-1 board, both LDAC and CLEAR pins are pulled-down to ground with a 10K resistor, respectively.

In the test, it sometimes runs as expected, but sometimes runs unpredictable. And I tried to change the output value of the AD5755-1, it didn't work. What step was I missing ?  

 

 

XVIEW

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