ELM327LP Datasheet, PDF (1/94 Pages) ELM Electronics – Automatically searches for protocols

ELM327L
OBD to RS232 Interpreter
Description
The ELM327L is a low voltage version of our
popular ELM327 integrated circuit. It supports all of
the features of our current ELM327 IC, and only
differs physically in how pin 6 is used.
The following pages discuss the ELM327L in
detail, how to use it and how to configure it, as well
as providing some background information on the
protocols that are supported. There are also
schematic diagrams and tips to help you to interface
to microprocessors, construct a basic scan tool, and
to use the low power mode. Because of the similarity
with the ELM327, much of this data sheet has been
copied from the ELM327 data sheet.
Throughout this document, we will use the term
‘ELM327’ to refer to either the ELM327 or the
ELM327L. If there is something different between
the two, we will be specific as to which it applies to.
Applications
• Diagnostic trouble code readers
• Automotive scan tools
• Teaching aids
Features
• Works with a 2.0V to 5.5V supply
• Universal serial (RS232) interface
• Automatically searches for protocols
• Fully configurable with AT commands
• Low power CMOS design
Connection Diagram
PDIP and SOIC
(top view)
MCLR
Vmeasure
J1850 Volts
J1850 Bus+
Memory
Filter Cap
LFmode
VSS
XT1
XT2
VPW In
ISO In
PWM In
J1850 Bus-
OBD Tx LED
OBD Rx LED
RS232 Tx LED
RS232 Rx LED
CAN Rx
CAN Tx
ISO L
ISO K
VDD
VSS
RS232 Rx
RS232 Tx
PwrCtrl / Busy
IgnMon / RTS
Block Diagram
4.00 MHz
LFmode 7
Memory
5
RS232Rx 18
RS232Tx 17
RS232
Interface
PwrCtrl / Busy 16
IgnMon / RTS 15
Power
Control
Filter Cap 6
LDO
Regulator
XT1 ⁹
10 _XT2
Command
and
Protocol
Interpreter
25 26 27 28
status LEDs
MCLR
1
A/D
Converter
Vmeasure
2
ISO 15765-4
SAE J1939
ISO 9141-2
ISO 14230-4
SAE J1850
PWM & VPW
23 24
21 22 12
OBD interfaces
3 4 14 13 11
ELM327L DSA
Elm Electronics – Circuits for the Hobbyist
www.elmelectronics.com
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