 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
ELM327LSS Datasheet(PDF) 9 Page - ELM Electronics |
|
||||||||||||||||||||||||||||||
ELM327LSS Datasheet(HTML) 9 Page - ELM Electronics |
|
|
9 / 94 page  9 of 94 ELM327L ELM327L DSA Elm Electronics – Circuits for the Hobbyist www.elmelectronics.com Communicating with the ELM327 The ELM327 expects to communicate with a PC through an RS232 serial connection. Although modern computers do not usually provide a serial connection such as this, there are several ways in which a ‘virtual serial port’ can be created. The most common devices are USB to RS232 adapters, but there are several others such as PC cards, ethernet devices, or Bluetooth to serial adapters. No matter how you physically connect to the ELM327, you will need a way to send and receive data. The simplest method is to use one of the many ‘terminal’ programs that are available (HyperTerminal, ZTerm, etc.), to allow typing the characters directly from your keyboard. To use a terminal program, you will need to adjust several settings. First, ensure that your software is set to use the proper ‘COM’ port, and that you have chosen the proper data rate - this will usually be 38400 baud (if PP 0C has not been changed). If you select the wrong ‘COM’ port, you will not be able to send or receive any data. If you select the wrong data rate, the information that you send and receive will be all garbled, and unreadable by you or the ELM327. Don’t forget to also set your connection for 8 data bits, no parity bits, and 1 stop bit, and to set it for the proper ‘line end’ mode. All of the responses from the ELM327 are terminated with a single carriage return character and, optionally, a linefeed character (depending on your settings). Properly connected and powered, the ELM327 will energize the four LED outputs in sequence (as a lamp test) and will then send the message: ELM327 v2.1 > In addition to identifying the version of this IC, receiving this string is a good way to confirm that the computer connections and terminal software settings are correct (however, at this point no communications have taken place with the vehicle, so the state of that connection is still unknown). The ‘>’ character that is shown on the second line is the ELM327’s prompt character. It indicates that the device is in the idle state, ready to receive characters on the RS232 port. If you did not see the identification string, you might try resetting the IC again with the AT Z (reset) command. Simply type the letters A T and Z (spaces are optional), then press the return key: >AT Z That should cause the leds to flash again, and the identification string to be printed. If you see strange looking characters, then check your baud rate - you have likely set it incorrectly. Characters sent from the computer can either be intended for the ELM327’s internal use, or for reformatting and passing on to the vehicle. The ELM327 can quickly determine where the received characters are to be directed by monitoring the contents of the message. Commands that are intended for the ELM327’s internal use will begin with the characters ‘AT’, while OBD commands for the vehicle are only allowed to contain the ASCII codes for hexadecimal digits (0 to 9 and A to F). Whether it is an ‘AT’ type internal command or a hex string for the OBD bus, all messages to the ELM327 must be terminated with a carriage return character (hex ‘0D’) before it will be acted upon. The one exception is when an incomplete string is sent and no carriage return appears. In this case, an internal timer will automatically abort the incomplete message after about 20 seconds, and the ELM327 will print a single question mark (‘?’) to show that the input was not understood (and was not acted upon). Messages that are not understood by the ELM327 (syntax errors) will always be signalled by a single Overview The following describes how to use the ELM327 to obtain information from your vehicle. We begin by discussing just how to ‘talk’ to the IC using a PC, then explain how to change options using ‘AT’ commands, and finally we show how to use the ELM327 to obtain trouble codes (and reset them). For the more advanced experimenters, there are also sections on how to use some of the programmable features of this integrated circuit as well. Using the ELM327 is not as daunting as it first seems. Many users will never need to issue an ‘AT’ command, adjust timeouts, or change the headers. For most, all that is required is a PC or smart device with a terminal program (such as HyperTerminal or ZTerm), and a little knowledge of OBD commands, which we will provide in the following sections… |
Similar Part No. - ELM327LSS |
|
Similar Description - ELM327LSS |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
