MPC5744P chip ADC sampling, the reference voltage is 5V ,ADC0 and ADC1 sampling port peripheral reference voltage circuits are the same. The software is configured with ADC0 port 0 channel, ADC1 port 0 channel sampling at the same time, the external input analog voltage has 0 ~ 5 V change; Phenomenon: ADC0 port 0 channel sampling is normal, external voltage 2.5 V shows AD value 2045; When the external voltage of the ADC1 port 1 channel is 2.5V, the AD value 1750A DC0 changes linearly with the external voltage analog signal, and the ADC1 changes linearly with the external voltage analog signal (0 v corresponding to AD value 0 V to 5 v to AD value 4095, intermediate nonlinearity).
May I ask which points may have caused this phenomenon to occur?