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Anonymous
Not applicable

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:

   

Vout=(Vrefhi-AGND)*ACap/FCap+AGND

   

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

   

Vout(max)=3.76V

   

Vout(min)=2.5V

   

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

   

#define

   

 

 

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

unsigned

 

unsigned

 

int

 

 

void

{

DAC6_Start(DAC6_HIGHPOWER);

 

BUFFER_Start(BUFFER_HIGHPOWER);

 

 

{

 

 

DAC6_WriteStall(bDACValue);

 

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

 

 

 

 }/*while*/

    char    bDACValue = DAC_MAX;     // Variable for the DAC value     char    j;     // Variable for an index     i;        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       

} /*main*/

   

Anyone could tell me what's going on?  Thanks

   

 

   

   

 

   

 

   

   

#include

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3 Replies
Anonymous
Not applicable

i have same problem if you get any hint please help me also

   

i dont get perfect 3.3 and 0 voltage on analog pin by using DAC 
actually when i enter 0 offset i its function { DAC8_1_WriteBlind(BYTE bOutputValue);} it should give me 0 volt output but it give 0.38 volt and when i set 254 offset it gives me 2.95 volts,it should give me 3.3 volt
 i am using this chip on 3.3 voltage..

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Anonymous
Not applicable

i think you need to select

   

ref mux =(Vdd/2)+/-(Vdd/2)

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

Do you have OpAmp Bias andA_Buff_Power, global resources, set

   

to high power ? The CM range of analog amps is affected by their

   

bias. Datasheet covers this in specs.

   

 

   

Also depends on what part you are using. See V swing analog buffer

   

below.

   

 

   

    

   

         

   

http://www.cypress.com/?rID=2746     AN13666

   

 

   

 

   

Regards, Dana.

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