1. MegaSquirt and MegaSquirt Logo are trademarks of BG Soflex, LLC. MegaShift 4L60E Transmission Controller GPIO Program

2. 2 MegaShift 4L60E Controller Overview Dedicated controller for the electronically shifted General Motors RWD 4-speed automatic transmission Uses the GPIO hardware, and 4L60E embedded code (MegaShift code) Only controls the forward gears. You still require a mechanical shifter to place the transmission into Park, Reverse, or Neutral

3. 3 MegaShift 4L60E Controller Features Fully configurable automatic or manual mode using standard MegaTune and appropriate INI file Provisions for 'paddle' shifters on steering wheel (or anywhere else) Uses CAN network to get rpm, MAP (or TPS) from MS (or can hook MAP/TPS direct) LED Indicators for: current gear, Manual/Auto, Torque converter clutch lock-up Error codes reported to MT to indicate out-of-range VSS, current gear available for MS II

4. 4 MegaShift 4L60E Controller Shift Modes - Auto Gear selected according to a 4 gear by 12 rpm x 12 kpa (or tps%) shift table which selects the gear based on the current speed and load TCC engagement if map is below a threshold (in 4th gear) TCC engagement in 2nd and 3rd gear if trans temp is high

5. 5 MegaShift 4L60E Controller Shift Modes – Auto (Cont’d) In shift_mode=2, the trans can go directly to the target gear from the table, otherwise it shifts sequentially until it reaches the target gear Hysteresis built in to shift mode and TCC control to prevent hunting

6. 6 MegaShift 4L60E Controller Shift Modes – Manual Full manual control, unless (optionally) a shift would create an rpm > a user-specified redline or < user-specified min TCC engagement only if transmission temperature is high (>180°F) and MAP is low Torque converter clutch always unlocks during downshifts. It unlocks under certain conditions during upshifts, depending on the vehicle speed and engine MAP. It is safe to upshift under light load while the TCC is locked. Most OEM systems keep the torque converter clutch applied during light throttle upshifts.

7. 7 GPIO Hardware While the GPIO board must be built with the appropriate configured circuits in place, it does not require any other external circuits or special build modifications. That's because the GPIO was built with this application in mind.

8. 8 4L60E/GPIO Port Assignments

9. 9 4L60E/GPIO Port Assignments – Cont’d The transmission temperature is sensed by an internal temperature sensor (it has the standard GM temp. sensor response curve) The two MegaSquirt PWM channels are used for the pressure control solenoid and the 3/2 shift solenoid. All other controls are simple on/off switches

10. 10 Codewarrior Compiler The 4L60E code is written in the C programming language (not assembly language). There are lots of resources on the internet and in bookstores for writing C programs. The C 4L60E for GPIO code was developed entirely on Codewarrior 4.6 Special Edition. This compiler is available for free from Freescale (which used to be Motorola): http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=CWS-H12-STDED-CX You have to register to get the software. The Special Edition has a 32K compile limit, and a maximum of 32 files. The 4L60E code is well under those limits. For a brief introduction to programming the HCS12 try: https://www.ee.nmt.edu/~rison/ee308_spr06/lectures.html (May have a security certificate error, proceed anyways.)

11. 11 Codewarrior Compiler The code has been written in as simple a manner as possible, and lots of comments, including background information on things like setting up timer ports, etc. to make writing and modifying code as easy as possible for the novice. The source code should be available when you read this, or shortly thereafter.