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

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

Summary: 3 Replies, Latest post by glenn-edgar_1523231 on 04 Nov 2016 12:42 PM PDT
Verified Answers: 1
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glenn-edgar_1523231's picture
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22 posts

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.

user_1377889's picture
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9583 posts

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

 

Bob

vsrs's picture
Cypress Employee
23 posts

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

glenn-edgar_1523231's picture
User
22 posts

Thanks VSRS

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

Glenn

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