How to use the internal 1.2v reference for ADC on K60 ?

[danielchai]

Hi All,

I am using the MQX10.4 and MQX4.0.1.

I was trying to use the internal 1.2v reference for adc0.

I used ioctl(adc_dev0, ADC_IOCTL_SET_REFERENCE, ADC_REF_VREF), but when I check the register SC2 reference bits still shows 00.

I also tried to manually set the VREF_SC  and SC2 register.

VREF_SC |= 0xA0;

ADC0_BASE_PTR ->SC2 |= 0x01;

but the reading result still based on VREFH and VREFL not based on internal 1.2v.

Any suggestion about this?

Thanks.

[danielchai · Accepted solution]

The ADC_REF_VREF does not work. But change it to ASC_REF_VALT, IT WORKS.

[DavidS]

Hi Daniel,

Sorry for trouble but very glad you resolved it.  Good debugging on your part.

There is also Freescale AN4568 that uses internal voltage reference for Kinetis K series that might help others.

Regards,

David