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Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Tue Jul 17, 2012 9:42 pm
by thebigmacd
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.
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Tue Jul 17, 2012 10:04 pm
by Peter
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.
viewtopic.php?f=5&t=1531
Just out of curiosity have you used the
PropellerGCC yet?
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Tue Jul 17, 2012 10:10 pm
by thebigmacd
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
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Tue Jul 17, 2012 10:16 pm
by Fred
Peter wrote:Just out of curiosity have you used the
PropellerGCC yet?
Propeller just got WAY more attractive! Cool :-)
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Tue Jul 17, 2012 10:20 pm
by thebigmacd
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.
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.
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Tue Jul 17, 2012 10:28 pm
by thebigmacd
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
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Thu Jul 19, 2012 1:04 am
by thebigmacd
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?
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Wed Jul 25, 2012 12:45 am
by thebigmacd
The output shaft speed sensor tone ring has 24 teeth.
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Thu Jun 05, 2014 2:12 am
by russian
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?
Re: Chrysler 42RE Transmission Controller Brainstorming
Posted: Sun Jun 08, 2014 3:33 am
by thebigmacd
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.