2 Replies Latest reply on May 21, 2010 10:57 AM by userc_42488


      I input a 6bits_code_min=0dec or 6b_code_max=62dec value into the DAC6 by means WriteStall API and I get unexpected Voutput value.


      Theoretically the DAC6 datasheets told us:




      Taking into account my reference Vdd/2+/-BandGap I must to have:






      Instead of this I obtain a more or less a  Vout=3.7 V  and after that the value is going down until reach


      aproximattely 2.5V. I put the analog outputs in High Z.


      The C code is simple:










      "PSoCAPI.h" // PSoC API definitions for all User Modules







          DAC_MAX (    62    )     // Define max DAC value as 62    




              char    bDACValue = DAC_MAX;     // Variable for the DAC value    


              char    j;     // Variable for an index    







          main()     // Start DAC6 in HIGH power mode    



          while    (    1    )     // Repeat forever    



          //for(j=0; j<62; j++){    



      for(i = 0xFF; i != 0; i--); // Delay loop

          for    (i =     0xFF    ; i !=     0    ; i--);     // Delay loop    


          for    (i =     0xFF    ; i !=     0    ; i--);     // Delay loop   



      }/*while*/ /*main*/


      Anyone could tell me what's going on?  Thanks





        • 1. Re: DAC6

          Some points to check:


          1. What is the column clock setting for the DAC?  Depending on the power you operate, there is a maximum column clock limitation.  If the column clock is more than the limit, then the DAC output will not be as expected.


          2. Is the DAC set to signed or unsigned?  If set to unsigned, you will get REFLO at the output, ie, 1.3V.  For a value of 62, you should get REFHI which is 3.8V

          • 2. Re: DAC6

            I'm using a 136KHz frecuency column clock. Much lower than the 3.2MHz  let it with high Power


            use modele way.


            The DAC is signed?


            The input data is OffsetBinary. I shoudl to obtain following the formula a values between 2,6V and 3,9V.


            I got a ramp, but is not between the values I hope.