Based on STM32H7 oscilloscope

This is a replica of the Hardwood Classroom AFE03 oscilloscope expansion board, with some components replaced. The hardware and signal conditioning circuit implementation are
explained below. We will first briefly introduce the analog input and output channels on the oscilloscope expansion board, and then explain the design and calculation methods in detail later. The signal enters from the oscilloscope input terminal. Here, a 1MΩ input impedance is achieved through a series resistor voltage divider, generating two signals for selection: one is a direct input, and the other is attenuated to 1/20. A relay is used as a switch to select either the direct signal or the attenuated signal to enter the first-stage non-inverting amplifier. The non- inverting amplifier performs two tasks: first, it amplifies the input signal at the non-inverting terminal by a factor of two; second, it shifts the amplified signal by 1.65V, calculated as Vo = 1.65 + 2*Vi. Therefore, the overall gain of the corresponding circuit is 2 times or 1/10 times. The output of the non-inverting amplifier is sent to the STM32H750 ADC. The trigger/frequency measurement signals AnalogA and AnalogB, along with the DC reference level (generated by one of the H750's DACs), are passed through a comparator to generate a square wave signal, which is then fed into the STM32H750's timer for frequency measurement. DAC_OUT2 is the DC reference level, emitted through the STM32H750's internal DAC2 configuration. The output channel uses a two-stage RC filter to function as a low-pass filter . The output amplifier amplifies the non-inverting input by 6 times and then shifts the amplified signal by -10V before outputting it. In conclusion, this training camp was time-constrained, and some functions were not yet fully debugged; further improvements will be made later.