My first oscilloscope

This project is for circuit design reference only. You are welcome to perform secondary development and design according to your own needs.
The I/O allocation in this project is only applicable to the Hardwood Classroom H750 core board. Please refer to the schematic diagram for specific allocation details
. Signal conditioning circuit implementation:
Below, we will briefly introduce the analog input and output channels on the AFE03 board. We will then introduce the design and calculation methods in detail later.
INA, INB: The input terminals of the oscilloscope. The pocket instrument sends an analog signal and connects here. 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.
gain: The selector switch selects either the direct signal or the signal attenuated to 1/20 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 two times; 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.
AnalogA and AnalogB: The analog signals, amplified and shifted by the inverting amplifier, are connected to the STM32H750 development board and enter the H750's ADC.
TrigerA and TrigerB: The square wave signals generated by AnalogA, AnalogB, and the DC reference level (generated by one of the H750's DACs) after passing through a comparator enter the STM32H750's timer for frequency measurement.
DAC_OUT1: The DC reference level is output through the STM32H750's internal DAC2
. The analog input channel
includes signal conditioning implemented with resistor dividers and operational amplifiers, and a square wave output implemented with a comparator.
The STM32H750's DAC1 output waveform ranges from 0-3.3V.
A second-order RC filter implements a low-pass filter function.
A resistor divider and buffer convert the 5V input to a low-impedance 2V output, which is then amplified by -5 times for shifting the output signal.
 
The output amplifier performs two functions: first, it amplifies the non-inverting input by 6 times; second, it shifts the amplified signal by -10V before outputting it. The calculation formula is Vo = -10 + 6 * Vi.
The voltage divider network is used to achieve better results when outputting small signals by utilizing analog circuit voltage division.
Analog input channel introduction:
This includes signal conditioning implemented with resistor voltage dividers and operational amplifiers, and square wave output implemented with comparators.
Attachment:
Demonstration video
; Test video link:
GG老刘's video submission - GG老刘's video sharing - Bilibili (bilibili.com)