VREFBUF control and status register
| ENVR | Voltage reference buffer mode enable This bit is used to enable the voltage reference buffer mode.  |  
| HIZ | High impedance mode This bit controls the analog switch to connect or not the VREF+ pin. Refer to Table196: VREF buffer modes for the mode descriptions depending on ENVR bit configuration.  |  
| VRR | Voltage reference buffer ready  |  
| VRS | Voltage reference scale These bits select the value generated by the voltage reference buffer. Other: Reserved  |