RM48L952ZWT ADREFHI, ADREFLO, and ADxEVT signals

Hello Tammy,

The ADREFLO and REFHI pins are analog inputs. These pins are used to define the range of the ADC and, ultimately, they weighting/resolution of each bit in the ADC results. Another way to look at this is that these inputs define the saturation points of the ADC. i.e., if ADREFLO is set to GND, the minimum voltage for the ADC will be GND such that a ADC count of 0x000 would equate to 0V. Likewise, ADREFHI would be the upper saturation point. If ADCREFHI is 3V, the maximum voltage capable of being measured is 3V which would correspond to a ADC count of 0xFFF. In general, the resolution of each count or bit would be according to the formula (ADREFHI-ADREFLO)/4096. In this case where ADREFHI=3V and ADREFLO=0V, each bit would be 0.000732421875V/bit.

ADxEVT, is either an input or output dependent on SW configuration of the pin. If used as its functional purpose, it is the ADC Event trigger input that can be used to trigger conversions on the event group. This could be hooked up to an external source such as an ASIC that has an algorithm that determines when the ADC in the MCU should sample voltage(s). It can also be configured as a GPIO and used as any other GPIO. More information on the EVENT group triggering and the ADCEVT pin can be found in the TRM.