Transcript Freescale presentation template

MegaShift 4L60E Transmission
Controller GPIO Program
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MegaShift 4L60E Controller
Overview
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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
MegaShift 4L60E Controller
Features
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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
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VSS, current gear available for MS II
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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
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MegaShift 4L60E Controller Shift
Modes – Auto (Cont’d)
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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
MegaShift 4L60E Controller Shift
Modes – Manual
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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.
GPIO Hardware
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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.
4L60E/GPIO Port Assignments
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4L60E/GPIO Port Assignments –
Cont’d
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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
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.)
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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.
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