STC-U7 offline downloader

STC-U7 offline downloader is made according to STC company's open source drawings. On this basis, I added lithium battery power supply, which can be used for mobile offline. The red circle 1 is the microcontroller and design buttons. The red circle 2 is offline downloading. It is an SPI memory used to store user programs. The red circle 3 is the output IDC interface function, which is marked with silk screen. The red circle 4 is the offline download trigger button. The red circle 5 is to control the external power supply transistor. The red circle 6 is the sound drive circuit The circuit in red circle 7 is a USB to serial port circuit with a communication indicator light. The circuit in red circle 8 is for a 3.3V power supply microcontroller. If you are using a 5V microcontroller, you don’t need to solder U5 and replace the D2 diode with a 0 ohm 1206 resistor. . The red circle 9 is the lithium battery boost 5V circuit, which is used for offline downloading. If you do not need to move the offline download, you do not need to weld the secondary circuit. The red circle 10 is the working status indicator light of the offline downloader. Offline and online downloads are successful. It will keep flashing. If the download is unsuccessful, the red circle will go out. 11 is the permission switch to update the U7 downloader firmware. PCB blank board video link: https://v.youku.com/v_show/id_XNDMzNDAwOTM0OA==.html?spm=a2h3j. 8428770.3416059.1