SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
The ADC modules share VREFHI and VREFLO inputs. In external reference mode, these pins are used as a ratiometric reference to determine the ADC conversion input range.
See Section 15.13.6 for information on how to supply the reference voltage.