Is AREF pin break-out usable on FRDM-K64F?

[TodorTodorov]

Hi everyone,

If I read the board schematic correctly, the VREFH pin is tied to VDD through a jumper resistor (R54), and the jumper resistor (R53) which ties VREFH to the AREF break-out pin on connector J2 is not populated. I need to be able to apply an external 2.048 reference voltage via the AREF pin, but the way I see it, this won't be possible without performing surgery on the board. :smileysad:

Is this correct?

I also looked at the board reference guide and at the K64F sub-family datasheet, but was unable to find any way to achieve an internal reference voltage of 2.048V, except if I power the whole board from that voltage. It is either VDD or 1.2V.

Is there any chance I missed something and this is achievable either on the AREF pin-out without taking a soldering iron to the board, or through some register setting in the MCU?

Thanks for your help!

[miduo]

No, there has no register to setting for this purpose. (Besides the ADC_REFSEL). For other reference voltage other than VDD or 1.2V, you should route out the pin from J2.