ELM322 Datasheet | ELM Electronics

Description Since the 1996 model year, North American automobiles have been required to provide an OBD, or On Board Diagnostics, port for the connection of test equipment. Data is transferred serially between the vehicle and the external equipment using this connection, in a manner specified by the Society of Automotive Engineers (SAE) standards. In addition to operating at different voltage levels, these ports also use a data format that is not patible with the standard used for personal puters. The ELM322 is an 8 pin integrated circuit that is able to change the data rate and reformat the OBD signals into easily recognized ASCII characters. This allows virtually any personal puter to municate with an OBD equipped vehicle using only a standard serial port and a terminal program. By also enhancing it with an interface program, hobbyists can create their own custom scan tool. This integrated circuit was designed to provide a cost-effective way for experimenters to work with an OBD system, so a few features such as RS232 handshaking, variable baud rates, etc., have not been implemented. In addition, this device is only able to municate using the 10.4KHz J1850 VPW protocol that is monly used in General Motors and some Daimler Chrysler vehicles. Applications - Diagnostic trouble code readers - Automotive scan tools Features - Low power CMOS design - High current drive outputs - Crystal controlled for accuracy - Fully configurable using AT mands - Standard ASCII character output - High speed RS232 munications - 10.4 KHz J1850 VPW protocol Connection Diagram PDIP and SOIC (top view) VDD 1 XT1 2 XT2 3 OBDIn 4 8 VSS 7 OBDOut 6 Tx 5 Rx Block Diagram 3.58 MHz XT1 2 3 XT2 Timing and Control Tx 6 Rx 5 RS232 Interface Interpreter OBD Interface 4 OBDIn 7 OBDOut ELM322DSF Elm Electronics - Circuits for the Hobbyist < http://.elmelectronics./ > 1 of 18 Pin Descriptions VDD (pin 1) This pin is the positive supply pin, and should always be the most positive...