PSoC62 : SAR ADC Vref range

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role_1685151
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Hi.

I'm reviewing about PSoC62 ADC. The power domain of PSoC6 is max 3.6V at datasheet.

I know PSoC6 Vref can be selected to System bandgap(1.2V) or VDDA/2 or VDDA or External device pin.

pastedImage_0.png

I have any questions.

1. Does it be possible to use adc input from 0~3.3V in Mbed platform? If possible, How do I control firmware? I want you to let me know sample code if you have one.

2. When VDDA is 3.3V and Vneg for Single ended is Vref as following, Is that mean Input range is 0 to 6.6V?

pastedImage_1.png

Thanks

Robert.

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

Hi Robert,

We will get back to you on the question 1.

Regarding question 2, yes your understanding is right. The ADC results will be spread over this range. But the input range of ADC cannot exceed the input range of the PSoC device. For a 3.6V VDDA max, this will be maximum voltage the PSoC device can support. So this is the maximum range of input for the device. You might not be able use the complete range for a Vref of 3.3V For a lesser reference voltage, you should be able use the ADC on complete range.

Best Regards,
Vasanth

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2 Replies
Vasanth
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250 sign-ins 500 solutions authored First question asked

Hi Robert,

We will get back to you on the question 1.

Regarding question 2, yes your understanding is right. The ADC results will be spread over this range. But the input range of ADC cannot exceed the input range of the PSoC device. For a 3.6V VDDA max, this will be maximum voltage the PSoC device can support. So this is the maximum range of input for the device. You might not be able use the complete range for a Vref of 3.3V For a lesser reference voltage, you should be able use the ADC on complete range.

Best Regards,
Vasanth

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DheerajK_81
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First comment on KBA First comment on blog 5 questions asked

Regarding your question 1, you can use the AnalogIn class in mbed to read analog input. Please find the sample codes here: AnalogIn - APIs | Mbed OS 5 Documentation

By default the configurations are set to use 12-resolution SAR ADC and Vref at 1.2V. You can find all the configurations in cyhal_adc.c file located under "mbed-os\targets\TARGET_Cypress\TARGET_PSOC6\psoc6csp\hal\src\".

Let me know if you have any further queries.

Regards,

Dheeraj