Voltage reference 1.2 V

You can configure pad MCA_IO2 to output a steady temperature-compensated 1.2 V output to use as a voltage reference for external peripherals.

CAUTION! For this functionality to work properly you must connect a 100 nF capacitor between MCA_IO2 and ground to filter ripple signals in the output. Connect the capacitor as close as possible to the module pad.

Kernel configuration

The 1.2 V voltage reference functionality is part of the MCA core driver and does not require any special kernel option.

Platform driver mapping

The MCA core driver is located at:

File	Description
drivers/mfd/mca-cc6ul-core.c	ConnectCore 6UL MCA core driver

Device tree bindings and customization

The voltage reference functionality does not require any device tree property.

Using the voltage reference output

The functionality is controlled by a sysfs entry. To enable the voltage reference on MCA_IO2 pad:

~# echo enabled > /sys/bus/i2c/drivers/mca_cc6ul/0-007e/vref

To disable it:

~# echo disabled > /sys/bus/i2c/drivers/mca_cc6ul/0-007e/vref

To read the current status of the pad:

~# cat /sys/bus/i2c/drivers/mca_cc6ul/0-007e/vref
disabled