STM32 source code project, schematic diagram, PCB file, CAN UART SPI-Flash power supply four-state input detection unit

This is actually only adjusted to the preliminary PCB that can run the UART. The others have not been actually debugged. However, if it is useful, friends can refer to the design and PCB. Because it is not fully debugged, the source code project has some redundant code and project files. It needs to be reorganized. Of course, if the board is useful, you can actually build your own project based on the principle. The compressed package contains a complete SCH and PCB, including power supply 5V, 3.3V, RS232, RS485, CAN, SPI-Flash, USB, and IO circuits.
The main functions implemented are a multi-IO, multiple 232/485, and a CAN communication. Among them, digital input detection detects four states through two IOs: high, low, floating, and there is a problem with the detection unit. This unit has corresponding Multisim simulation files under the SCH&PCB; directory. Truth table: L1 H1 value 0 0 INX_LH1 is high 0 1 Detection unit problem, maybe D6 and D7 are disconnected or INX_HL1 level is 1 0 INX_HL1 is floating, and the detection unit is OK; or INX_HL1 level is at the middle value 1 1 INX_LH1 is Low other exchangeable solutions: GPS vehicle monitoring system: complete set of terminal schematic PCB source code (stable and mature, can be connected to multiple peripherals); complete set of platform source code. LED screen: bus, rental, etc. schematic PCB; PC software, etc.; PDA control LED screen program source code. DVR: Small SD card recording solution, capable of taking 485 photos. Bus stop announcer, schematic PCB; PC software. Version 51, STM32 version. Car electric step driver board schematic PCB. PDA scanning wheel: barcode scanning, GPRS upload; complete set of terminal schematic PCB source code, server source code handheld bus ticketing terminal source code, can print receipts. The terminal price is extremely low. Stably used solid state relay principle and PCB (optocoupler isolation control triac). DC motor driver board.