The devicetree for the ccmp157-dvk appears to have vrefbuf enabled, but I read 0 volts at j41 pin 2 of the evk board. Is there something else I need to do to turn the internal reference on?
To enable the internal reference voltage on the ConnectCore MP15 Development Kit, you need to ensure that the VREFBUF is properly configured in the device tree. The VREFBUF is an internal voltage regulator that can be set to output different voltages at the VREF+ pin. Here are some steps you can follow:
Check Device Tree Configuration:
Ensure that the VREFBUF is enabled in the device tree. The configuration should look like this:
&vrefbuf {
regulator-min-microvolt = <2500000>;
regulator-max-microvolt = <2500000>;
status = "okay";
};
This configuration sets the VREFBUF to output 2.5 V.
Verify Hardware Connections:
Make sure that there are no hardware issues or incorrect connections on the board that might prevent the voltage from being read correctly at J41 pin 2.
Check Power Supply:
Ensure that the board is powered correctly and that all necessary power supplies are active.
Software Initialization:
Confirm that any necessary software initialization or drivers are loaded and running correctly to enable the VREFBUF.
If you have verified all these steps and still read 0 volts, there might be a hardware issue or a need for further software configuration. You may want to consult the detailed documentation or reach out to Digi Support for more specific troubleshooting: Submit a Support Case
https://www.digi.com/resources/documentation/digidocs/embedded/dey/4.0/ccmp15/bsp-adc_r_ccmp1.html