Optimus OBD II Reader - Page 1
Forum section: electronics / general

author: quanttrom
author_rank: Regular Contributor
timestamp: December 06, 2010, 10:28:18 pm
content: Intro:I am just starting on a long-term personal project. I want to make aOBDIIreader similar to theScanGaugebut in my own cool way. I am planning on using theOptimum Mini 3because I have only one set of working screens and 2 working PCBs for it. I can afford to damage one PCB and still be good. The device is essentially a set of 3 OLED displays mounted on 3 buttons. Looks cool and isn't made anymore but when it was made it was kinda overpriced.The Optimus has 3 screens 96x96 pixel w/ 16 bit color. Eg. it takes quite a bit of memory to store these colour graphics. My project would need to store the pictures/fonts/transitions and anything else I want to show in some kind of flash memory. I think the best solution for my problem would be an SD/MMC card and interfacing it to a micro-controller using SPI.I am planning on using MSP430 micro-controllers for the wrong reason: 1) I can get free samples 2) I already own a programmer... I haven't selected which one in particular but something that can handle 1x SPI + 1xUART(communicate with the Optimus Mini 3) + Memory Controller build in would be nice. I think I will need to use the memory controller and external memory of some small size because the images can get quite large( 442368 bits / ~ 55kbytes to store all of it).Question 1:What microcontroller would you recommend that can handle external RAM or have > 55Kbytes of RAM. It would be nice if I have a frame buffer for all 3 screens. If not, something with about ~18kbytes in order to be able to handle one screen at a time. I saw that the PIC18F8527 has a built in memory control unit which makes it kind of appropriate for my purpose. Any others?Question 2:Is there a library out there that can interface the MSP430 with a SD Card formated using the FAT file system? I didn't find any packaged ready solutions, only reference implementations for embedded platform that can be customized to be used for the MSP430.Question 3:Any general advice !??

author: quanttrom
author_rank: Regular Contributor
timestamp: February 02, 2011, 02:41:13 am
content: I finally had some time tonight and soldered programming wires onto the Optimus Mini 3 Micro-controller.It is based on PIC 18F8527.The dump I am getting has some assembly instructions in the begging but is mostly FFFF (NOP) and the Configuration Bits seem to show no code protection.What does a code locked pic look like when attempting to read the contents of it's program memory? It looks like this one is wide open.EM

author: Fraser
author_rank: Super Contributor
timestamp: February 08, 2011, 11:40:04 pm
content: I am not a programmer so cannot offer programming or MPU advice on your project design, but I do offer some common sense comment for your consideration....OBDII scanners are great devices and I use them regularly. I also have VAG-COM for my Audi and that is superb with it's ability to reconfigure and interrogate the many modules found in a modern car. CANbus is the current platform so should be supported by any future scanner design.I am not sure how you intend to develop and test your OBDII project but consider the risk to systems if you are going to use an operational vehicle as the test platform. A sub $100 test bed connected to a valuable vehicle could turn ugly if you scramble the EEPROM in an ECU or central CANbus gate controller. My Audi main control modules cost around $1500 a piece if you kill or scramble their configuration. OBDII diagnostic tool developers often use OBDII simulators rather than work out the bugs on a 'live patient' .