User Manual

Family Reference and Programming Manual
STN1100FRPMA www.obdsol.com 3 of 23
1.0 Overview
On-Board Diagnostics, Second Generation (OBD-II)
is a set of standards for implementing a computer
based system to control emissions from vehicles. It
was first introduced in the United States in 1994, and
became a requirement on all 1996 and newer US
vehicles. Other countries, including Canada, parts of
the European Union, Japan, Australia, and Brazil
adopted similar legislation. A large portion of the
modern vehicle fleet supports OBD-II or one of its
regional flavors.
Among other things, OBD-II requires that each
compliant vehicle be equipped with a standard
diagnostic connector (DLC) and describes a standard
way of communicating with the vehicle’s computer,
also known as the ECU (Electronic Control Unit). A
wealth of information can be obtained by tapping into
the OBD bus, including the status of the malfunction
indicator light (MIL), diagnostic trouble codes (DTCs),
inspection and maintenance (I/M) information, freeze
frames, VIN, hundreds of real-time parameters, and
more.
The STN11xx is an OBD to UART interpreter that
can be used to convert messages between any of the
OBD-II protocols currently in use, and UART. It is fully
compatible with the de facto industry standard ELM327
command set. Based on a 16-bit processor core, the
STN11xx offers more features and better performance
than any other ELM327 compatible IC.
2.0 Feature Highlights
• Fully compatible with the ELM327 AT command set
• Extended ST command set
• UART interface (baud rates from 38 bps to 10 Mbps
1
)
• Secure bootloader for easy firmware updates
• Support for all legislated OBD-II protocols:
o ISO 15765-4 (CAN)
o ISO 14230-4 (Keyword Protocol 2000)
o ISO 9141-2 (Asian, European, Chrysler vehicles)
o J1850 VPW (GM vehicles)
o J1850 PWM (Ford vehicles)
• Support for non-legislated OBD protocols:
o ISO 15765
o ISO 11898 (raw CAN)
• Superior automatic protocol detection algorithm
• Large memory buffer
• Voltage input for battery monitoring
• Available in TQFP-44 and QFN-44 packages
Note 1: Maximum theoretical baud rate. Actual maximum baud rate is application dependent and may be limited by driver
hardware.
3.0 Typical Applications
• Academic projects
• Automotive diagnostic scan tools and code readers
• Digital dashboards
• Fleet management and tracking applications
• OBD data loggers