This is the Open Source code for the Arduino based Renix Engine Monitor scan tool for Renix Equipped Jeeps from 1987 - 1990 This software is ment to stay Open Source.
This sketch will read a 1986 to 1990 Jeep Renix ECU's TX output, convert the hex string into useable measurements, and display them on a 16x2 LCD display allowing you to cylce through with buttons.
The circuit: An Adafruit Pro Trinket 5V 16MHz is connected to a 16x2 RGB LCD Screen and 5 buttons to provide the base scanner.
Components needed for communication:
just about any NPN Transisitor (I'm using a 2N3904)
a 1k and 3.3k Resistor
some wire and maybe a breadboard
The Renix Diagnostic Connector has 2 ports, D2 is the larger one. D2 Pins are numbered Bottom to Top, Left to Right if D1 is to the Left of D2
D1 D2
|4 1| <3 6 9 12 15|
|5 2) <2 5 8 11 14|
|6 3| <1 4 7 10 13|
Pin D2-1 is the ECU TX output, it is open collector to ground
Pin D2-4 is Ignition Postive (+)
Pin D2-7 is Ignition Ground (-)
We will use an NPN transistor to physically NOT (invert) the data and use some resistors to get the switching done
Arduino VIN pin -> Pin D2-4 Ign Pos(+) (Pro Trinket's voltage regulator is good to 16v)
Arduino 5V pin -> 3.3k resistor -> NPN Base <- Pin D2-1 TX (This is the ECU Input)
Arduino 5V pin -> 1k resistor -> NPN Collector <- Arduino RX Pin 0 (This is the Output to Arduino)
Arduino Gnd pin -> NPN Emitter <- Pin D2-7 Ign Gnd(-) (Negitive Rail)
Core Code RenixComm V 0.3 First incarnation January 7th, 2012 This revision Jan 17th, 2012 (Subrevision 24) Phil Andrews 2011, 2012 Thanks to Kes for help with the code
Additional Code Renduinix v0.72 Created July 13th, 2016 (v0.1) by Nick Risley Modified September 27th, 2016
Update Log: v0.1 Modified core code to display predetermined outputs on a 16x2 display v0.2 Interfaced buttons to cycle through a sensor array v0.3 Updated calculations to show proper, added more data points, and debounced button presses v0.4 Cleaned up formating, custom character, updated text data points, added permanent memory function v0.5 Update pins for Trinket Pro, fixed RPM calc, added custom backlight options, fixed freeze if no data was present v0.6 Migrated code to Switch Case, Revamped Menu System, improved stream acquisition, added settings and debug, unified gauge spacing, added custom Baud and PROG# Option v0.7 Added EEPROM presets and reset, revamped vehicle selection, released Alpha Models -0.71 Fixed Color and Software Info Menus -0.72 Fixed Vehicle Selection Menu