is the psoc 4m only a 11 bit a/d resolution in single channel

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
Anonymous
Not applicable

In single channel mode for the SAR_ADC, ( psoc 4m ), the max value appears to be 2047.  This is a 11 bit value.  It looks like the a/d is still acting like the a/d is running in differential mode, ie -2047 to 2047.  Sometime the ground measurement returns -1, which seems to indicate that a differential mode measurement is returned.

   

 

   

Is there a way to have the A/D return 0 to 4095, which is a 12 bit a/d range.

0 Likes
1 Solution
Vasanth
Moderator
Moderator
Moderator
250 sign-ins 500 solutions authored First question asked

Hi Glenn,

   

If you need 12bit resolution and unsigned result, it is possible. You can see the datasheet table attached. The procedure you have to follow is

   

1.Keep Vref select to external

   

2.Set Vref value to 2.5V

   

3.Make single ended negative input as Vref

   

4. You will be able to take single ended result format as unsigned and will be getting 12 bit resolution.

   

Only overhead here is 2.5V external ref. You have to connect this to Vref pin.

Regards,
VSRS

   

   

   

View solution in original post

0 Likes
3 Replies
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

Read datasheet pg 7 "Single ended negative input". Resolution will be 11 bits.

   

 

   

Bob

0 Likes
Vasanth
Moderator
Moderator
Moderator
250 sign-ins 500 solutions authored First question asked

Hi Glenn,

   

If you need 12bit resolution and unsigned result, it is possible. You can see the datasheet table attached. The procedure you have to follow is

   

1.Keep Vref select to external

   

2.Set Vref value to 2.5V

   

3.Make single ended negative input as Vref

   

4. You will be able to take single ended result format as unsigned and will be getting 12 bit resolution.

   

Only overhead here is 2.5V external ref. You have to connect this to Vref pin.

Regards,
VSRS

   

   

   

0 Likes
Anonymous
Not applicable

Thanks VSRS

   

Good heads up.  I used VDDA/2 as my external reference instead of an external pin.  Results works great.

   

Glenn

0 Likes