This feature is only present in 4.1.0 and later on the 4.x LTS branch, and in 5.3.0 and later in the 5.x developer prevent branch.
Set the ADC input reference. This does not affect the range of the ADC, which is always 0 - 3.3V with a 12-bit range (0 - 4095).
On nRF52840 devices, this call determines whether the ADC voltage reference is VCC (3V3), or the MCU internal voltage reference. On most devices, the default is
AdcReference::VCC (3V3). The exception is the Boron 404X, which defaults to
On RTL872x devices (P2, Photon 2), the ADC reference is always
AdcReference::INTERNAL and attempting to set it will return
Returns 0 on success, or a non-zero system error code.
// PROTOTYPE int analogSetReference(AdcReference reference); // EXAPLE analogSetReference(AdcReference::INTERNAL)
The valid values for analogSetReference are:
AdcReference::DEFAULTUse the default value for this device
AdcReference::INTERNALUse the MCU internal voltage reference if supported by the device
AdcReference::VCCUse VCC (3V3) as the voltage reference if supported by the device