USB-to-RS232 converter on desktop computers COM port does not work well, but most of them are not useful for notebook laptop com-port Serial not found. Based on PIC18F2455 microcontroller circuit diagram hex driver software and observation programs there. USB... Electronics Projects, PIC18F2455 OBD2 USB to RS232 converter circuits "microchip projects, microcontroller projects, " Date 2019/08/01