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Chrysler 42RE Transmission Controller Brainstorming 
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LQFP112 - Up with the play

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Starting to do some visualisations. Note that it is 35 C here today. I spent all day pulling wire and bending conduit in a mechanical room. Yuck.
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Keith MacDonald
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Tue Jul 17, 2012 9:42 pm
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I like though hole stuff better also. I do use quite a few breakout boards for things that don't come in diy type packages.

As far as the fets go it's pretty much 6 of one half a dozen of the other.

I'm also not a fan of the LM1815. http://forum.diyefi.org/viewtopic.php?f=5&t=1531

Just out of curiosity have you used the PropellerGCC yet?

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Tue Jul 17, 2012 10:04 pm
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LQFP112 - Up with the play

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Firmware tasks

The following tasks have to be performed by the processor. The load can be spread out across 8 x 20 MIPS cores and 16 hardware timers.

  • Monitor ignition power
  • Track statistics and save in EEPROM (more on this later)
  • Monitor 2 pulse input channels for engine speed and output shaft speed
  • Poll 2 ADC channels via SPI
  • Switch 4 digital outputs (3-4, TCC, Relay, OD light)
  • Modulate 1 PWM output (governor)
  • Communicate via serial (USB)
  • Convert raw input values into useful units
  • Perform logic decisions and set flags
  • Perform table lookups
  • Flash SCAN led

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Keith MacDonald
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Tue Jul 17, 2012 10:10 pm
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Peter wrote:
Just out of curiosity have you used the PropellerGCC yet?

Propeller just got WAY more attractive! Cool :-)

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Tue Jul 17, 2012 10:16 pm
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LQFP112 - Up with the play

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Peter wrote:
I like though hole stuff better also. I do use quite a few breakout boards for things that don't come in diy type packages.

As far as the fets go it's pretty much 6 of one half a dozen of the other.

I'm also not a fan of the LM1815. http://forum.diyefi.org/viewtopic.php?f=5&t=1531

Just out of curiosity have you used the PropellerGCC yet?


I get much better than short spikes from my twin LM1815s, but it did take some circuit tweaking.

No I haven't used PropellerGCC. To be honest I like the simplicity of SPIN and PASM. I'm more of a Python and assembler guy than C. I was going to mention it though, as it does make the product more attractive to a larger user base.

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Keith MacDonald
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Tue Jul 17, 2012 10:20 pm
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LQFP112 - Up with the play

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Fred wrote:
Peter wrote:
Just out of curiosity have you used the PropellerGCC yet?

Propeller just got WAY more attractive! Cool :-)


The best part is it has standard C libraries, so it acts more like Linux than just a plain old microprocessor.

http://propgcc.googlecode.com/hg/doc/Library.html

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Keith MacDonald
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Tue Jul 17, 2012 10:28 pm
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Basic Coding Milestones
(Somewhat in order of precedence)

#1 Boot/Debug

  • Dump predefined variables via serial <- basic testing interface
  • Reboot microprocessor on demand (trivial)
  • Respond via VGA/NTSC terminal to serial commands <- reduces need for a laptop later
  • Generate constant data stream when prompted, and stop when prompted <- datalogging framework
  • Set/unset flags via serial
  • Write fixed and floating point values to variables via serial

#2 Data Acquisition

  • Read and dump states of digital inputs: Ignition Power, Park/Neutral, OD Switch
  • Read and dump raw values from DAC: Transmission Pressure, Transmission Temp, Throttle Position, [Baro?] (Need an MCP3204 after all)
  • Calculate frequency of pulse inputs: Tachometer, Output Shaft Sensor

#3 Output Generation

  • Turn OD, SCAN LEDs on and off
  • Switch transmission solenoids on and off: Transmission Relay, 3-4 Shift, TCC Lockup
  • Generate PWM for Governor Solenoid

#4 Math

  • Convert analogue inputs to either fixed or floating point in Metric automotive units via table lookup or scaling
  • Convert Tach and OSS frequencies to RPM
  • Set/unset flags via value comparison <- for shift mode logic

#5 Logic

  • Boolean compare flags to set shift modes
  • Write mode-specific values to PWM and digital outputs
  • Profit?

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Thu Jul 19, 2012 1:04 am
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The output shaft speed sensor tone ring has 24 teeth.

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Wed Jul 25, 2012 12:45 am
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thebigmacd wrote:
#3 Output Generation

  • Turn OD, SCAN LEDs on and off
  • Switch transmission solenoids on and off: Transmission Relay, 3-4 Shift, TCC Lockup
  • Generate PWM for Governor Solenoid


So, how would 1-2-3 shift be controlled then? Is it all taken care by the single PWM for Governor Solenoid?

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Last edited by russian on Tue Jun 10, 2014 1:50 am, edited 1 time in total.



Thu Jun 05, 2014 2:12 am
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LQFP112 - Up with the play

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russian wrote:
thebigmacd wrote:
#3 Output Generation

  • Turn OD, SCAN LEDs on and off
  • Switch transmission solenoids on and off: Transmission Relay, 3-4 Shift, TCC Lockup
  • Generate PWM for Governor Solenoid


So, how would 1-2-3 shift be controlled them? Is it all taken care by the single PWM for Governor Solenoid?


Yes sir, it is. It simulates the old mechanical pressure control in non-electronic version of the transmission.

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Keith MacDonald
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Sun Jun 08, 2014 3:33 am
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