USB-RS232 converter does not work well on desktop computers, but useful for Notebooks without COM port, most laptop computers do not have Serial com-port. Circuit PIC18F2455 microcontroller based on the circuit diagram hex software driver and observation programs are available.
On PC desktops, RS-232 serial ports are disappearing from most computers (especially laptops) and are being replaced by USB connections. This project is to create simple ISO9141-2/14230-4 ELM323 compliant USB adapter for On-Board Diagnostic (OBD2) monitoring
This project is built around a new Microchip PIC18F2455/2550 8-bit microprocessor with USB power. The PIC18F2455 USB core is V1.1 and V2.0 compatible and operates at 1.5Mbps and 12Mbps respectively. The microprocessor has 2048 bytes of RAM and 24K Flash program memory; Plenty to implement OBD2 controller functionality using high-level C programming language.
The PIC18F2550 is basically the same as 32K Flash memory. The chip is available in the DIP28 package and with few external components allows the implementation of the ISO9141-2 and ISO14230-4 (KWP2000) protocol controller. The SAE OBD2 protocol is translated into ASCII character-based messages and displayed to the PC via the USB virtual COM interface.
It draws 5V power from the USB bus, which simplifies the circuit design. Freescale’s MC33290 chip provides an interface to the ISO9141/14230 bus. There are 3 LEDs that indicate USB connection status and OBD connection send/receive activity. The adapter has a dedicated connector for In-Circuit Serial Programming, see programming PIC18F2455. You can download firmware for 18F2455 and 18F2550 using this link.
USB OBD2 adapter on PIC18F2455 on pc desktops the rs-232 serial ports are about to disappear from most computers (especially from laptops), replaced by the usb connection. this project was begun as a response to build simple iso9141-2/14230-4 elm323 compatible usb adapter for on board diagnostic (obd2) monitoring.
Source: http://www.obddiag.net/projects.html USB to RS232 converter circuits Alternative link:
Password: 320volt.com
Published: 2008/01/13 Tags: microchip projects, microcontroller projects
24V to 12V Step Down DC DC Regulator LM2576
Integrated Switching Regulator LM2576 12 volts to 24 volts with a lowering circuit. National company produced by the LM2576 SIMPLE SWITCHER 3A Step-Down Voltage Regulator made with a nice application also of the circuit Protel designed along with the Sema and printing Node there half the power of 3 Amps few parts with a nice Switching Regulator circuit
24V to 12V LM2576 DC DC Converter
USB-zu-RS232-Konverter auf Desktop-Computern COM-Port funktioniert nicht gut, aber die meisten von ihnen sind nicht nützlich für Notebook-Laptop-Com-Port Serial nicht gefunden. Basierend auf PIC18F2455 Mikrocontroller-Schaltplan Hex-Treibersoftware und dortigen Beobachtungsprogrammen.
USB-OBD2-Adapter bei PIC18F2455 auf PC-Desktops Die seriellen RS-232-Ports verschwinden bald von den meisten Computern (insbesondere von Laptops) und werden durch die USB-Verbindung ersetzt. Dieses Projekt wurde als Reaktion auf den Bau eines einfachen iso9141-2 / 14230-4 elm323-kompatiblen USB-Adapters für die On-Board-Diagnose (obd2) gestartet.