Voltmeter and Ammeter

This project requires
you to design and build a digital voltmeter and ammeter. The core board uses the domestic Wuhan Xinyuan Semiconductor CW32 as the main controller.
Design tutorials and source code are available:
CW32 Digital Voltmeter and Ammeter Training Camp Project Tutorial Document | LCSC Development Board Technical Document Center
Video:
Step-by-Step Guide to Making a Voltmeter and Ammeter_bilibili.
Schematic Design Instructions:
This circuit is a basic replica of the circuit design from the LCSC training camp.
Five working modes are defined. The K1 key is used to switch display modes. The K2 key sets the parameter values ​​for the corresponding mode and saves them to FLASH. The K3 key returns to mode 0.
Mode 0: Displays normal voltage and current values ​​(the upper row of digital tubes displays the voltage value .V or .V automatically switches, the lower row displays the current value _.**A).
Mode 1: 5V voltage calibration value setting. The upper row of digital tubes displays 5.05. The lower row displays the current voltage value _.V or ._V. In this mode, the multimeter should be set to 5.00V to measure the measured bit. After pressing the K2 key, the current value is calibrated to the 5V voltage value.
Mode 2: 15V Voltage Calibration Setting. The top row of the digital display shows 5.15. The bottom row shows the current voltage value in _V or ._V. In this mode, the multimeter should be set to 15.0V when measuring the measured bit. Pressing the K2 key will calibrate the current value to 15V.
Mode 3: 0.5A Current Calibration Setting. The top row of the digital display shows A.0.5. The bottom row shows the current current value in _.**A. Pressing the K2 key will calibrate the current value to 0.5A.
Mode 4: 1.5A Current Calibration Setting. The top row of the digital display shows A.1.5. The bottom row shows the current current value in *.**A. Pressing the K2 key will calibrate the current value to 1.5A. The tutorial source code used in
the software instructions : Link: https://pan.baidu.com/s/12OWqnW4XG8EGxlk9wCQoqw?pwd=LCKF Extraction code: LCKF Physical demonstration instructions