GENERAL DESCRIPTION:
This device is a CMOS microcontroller which is designed to interface a personal computer or laptop with a
vehicle's On Board Diagnostic (OBD II) interface. It is intended to function with all three of the protocols used
by vehicle manufacturers to implement the OBD II system as defined by SAE and ISO specifications. The
OBD II system became mandatory for 1996 and up vehicles, but some vehicles were already fully or partially
compatible with OBD II requirements prior to 1996. The chip is not suitable for the earlier vehicles such as
OBD I.
The device is intended to function as a simple scan tool and is capable of sending and receiving any OBD II
message defined in SAE J1979 for any of the three types of OBDII bus implementations (PWM, VPW, ISO
9141-2). It can also be used as an inexpensive interface for custom instrumentation monitoring various
vehicle parameters such as speed, RPM, coolant or intake air temperature, engine load, intake air flow rate,
etc.

FEATURES:
Operating Voltage 5.0 V
Operating Current 5 Ma. Typ
Clock: 20 MHz
Inputs: (0-5V levels)
Serial Input (19200 Baud)
PWM receive
VPW receive
ISO 9141-2
Outputs (0-5V levels)
Serial output (19200 Baud)
PWM transmit bus+ (inverted)
PWM transmit bus- (inverted)
VPW transmit
ISO 9141-2 L line transmit (inverted)
ISO 9141-2 K line transmit (inverted)