Help needed, crank signal generator. <solved>

[MPC001]

A bunch of arbitrary syntax stuff.
I got it working less than a minute ago.
Just need to add back the speed variation input, then figure out some simple analog input hysteresis code.
And I might need to invert polarity.

Code: Select all

int TPS = 0;
int sequence[48] = {0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0};
int cam[48] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
int tooth = 0;
int low = 0;
int high = 0;
int RPMlow = 0;
int RPMhigh = 0;
int math = 1;
int halfdone = 1;
int done = 1;
int width = 1;
unsigned long previousmicros = 0;

void setup() {
//pinMode(A0, INPUT);
pinMode(1, OUTPUT);

}

void loop() {

if (halfdone == 0) {
  if (micros() - previousmicros >= RPMlow) {
      halfdone = 1;
      done = 0;
      digitalWrite(1, HIGH);
      previousmicros = micros();
    }
  }
if (done == 0) {
  if (micros() - previousmicros >= RPMhigh) {
      done = 1;
      math = 1;
      digitalWrite(1, LOW);
      previousmicros = micros();
    }
  }
   
if (math == 1) {
tooth++;
if (tooth == 48) {
  tooth = 0;
  }

TPS = 666; 
width = sequence[tooth];
cam[tooth];
if (width == 0) {
  low = 1;
  high = 2; 
  }
if (width == 1) {
    low = 2;
    high = 1;
  }
halfdone = 0;
math = 0;
RPMlow = low * TPS;
RPMhigh = high * TPS;
} 
}

Very interesting! While the 24X waveform looks correct for GM Gen III LS, I can't figure how you get that waveform from the 48 point array. If i run that array on an E40, while rpm is rock solid, the crank error logic gets upset.

[AngelMarc]

Which microcontroller are you using? Performance seems to vary, more than just max speed. Best of what I have was the Pi Pico. And what are you using to step up the voltage? Pretty sure E40 is still 12 volt signal. Some of the variation of the TC44xx drivers invert the signal.

If it is just an inverted driver problem swapping these lines would do it.
digitalWrite(1, HIGH);
digitalWrite(1, LOW);

Code: Select all

if (halfdone == 0) {
  if (micros() - previousmicros >= RPMlow) {
      halfdone = 1;
      done = 0;
      digitalWrite(1, HIGH);
      previousmicros = micros();
    }
  }
if (done == 0) {
  if (micros() - previousmicros >= RPMhigh) {
      done = 1;
      math = 1;
      digitalWrite(1, LOW);
      previousmicros = micros();
    }
  }
  

[AngelMarc]

int sequence[48] =
Is the 24x pattern twice, so one pass can have cam signal low and the other high.
A full array cycle is 2 crank rotations.

[AngelMarc]

Code: Select all

if (width == 0) {
  low = 1;
  high = 2; 
  }
if (width == 1) {
    low = 2;
    high = 1;
  }

Dictates whether you get

Capture.PNG

or

Capture1.PNG

from

Capture2.PNG

Code: Select all

RPMlow = low * TPS;
RPMhigh = high * TPS;

Scales for different RPM

Code: Select all

if (halfdone == 0) {
  if (micros() - previousmicros >= RPMlow) {
      halfdone = 1;
      done = 0;
      digitalWrite(1, HIGH);
      previousmicros = micros();
    }

Is the low portion of tooth.

Code: Select all

if (done == 0) {
  if (micros() - previousmicros >= RPMhigh) {
      done = 1;
      math = 1;
      digitalWrite(1, LOW);
      previousmicros = micros();
    }
  }

Is the high portion.
If I remember right, I had to invert them because Arduino bug or something.

Code: Select all

if (math == 1) {
tooth++;
if (tooth == 48) {
  tooth = 0;
  }

Cycles through the array one at a time.

Code: Select all

int math = 1;
int halfdone = 1;
int done = 1;

Are just flags to dictate the order of each if statement.

[antus]

Inversion depends on the configurarion of the gpio pin.

[AngelMarc]

It did what it did by default, so I wrote my code different and moved on with my life.

[MPC001]

Thank you AngelMarc for the reply. Using an Arduino Nano @ 16meg with 5V I/O. So not the 133meg (?) clock speed of Pico RP2040. And yes realize E40 runs 12V CRK/CAM sensor supplies, but not confirmed that the signal lines were 5V or 12V and they run ok at 5V at present so didn't want to risk an expensive & hard to get E40 by driving at 12V without knowing for sure. (no live in car example to check with CRO.)

I did run up 120 point (Crank + Cam) arrays for 3 degree resolution state changes & the crank error logic stopped protesting. The crank speed is more stable without the CAM drive array in the loop, but then the CAM error logic of course complains.

Which microcontroller are you using? Performance seems to vary, more than just max speed. Best of what I have was the Pi Pico. And what are you using to step up the voltage? Pretty sure E40 is still 12 volt signal. Some of the variation of the TC44xx drivers invert the signal.

[MPC001]

Understood!

int sequence[48] =
Is the 24x pattern twice, so one pass can have cam signal low and the other high.
A full array cycle is 2 crank rotations.

[AngelMarc]

High speed square waves from a 32u4 (also 5 volt) start looking rounded. I don't remember what frequency that's noticable, but I don't see it at stupid speeds with the ESP32 S3 or the Pi Pico.

[MPC001]

Awesome! ThankYOU very much for taking the time to explain. Most appreciated. I suspected your additional code below was the answer but couldn't wrap my head around it. Will study in greater depth now till i get it. (I hadn't included originally with 48 point array as I didn't understand it. Doh!).

Originally I had written some "bit banger" (?) code (3 lines with a timer for EVERY state change - w/o an array) over a decade ago for an AVR Teensy 8 bit @ 8 meg., but the addition of the analogread for speed control disrupted the timing loop so much it would wouldn't maintain synch. (24x & 58x modes).

More modern silicon to the rescue!

Thankyou!

Code: Select all

if (width == 0) {
  low = 1;
  high = 2; 
  }
if (width == 1) {
    low = 2;
    high = 1;
  }

Dictates whether you get
Capture.PNG
or
Capture1.PNG
from
Capture2.PNG

Code: Select all

RPMlow = low * TPS;
RPMhigh = high * TPS;

Scales for different RPM

Code: Select all

if (halfdone == 0) {
  if (micros() - previousmicros >= RPMlow) {
      halfdone = 1;
      done = 0;
      digitalWrite(1, HIGH);
      previousmicros = micros();
    }

Is the low portion of tooth.

Code: Select all

if (done == 0) {
  if (micros() - previousmicros >= RPMhigh) {
      done = 1;
      math = 1;
      digitalWrite(1, LOW);
      previousmicros = micros();
    }
  }

Is the high portion.
If I remember right, I had to invert them because Arduino bug or something.

Code: Select all

if (math == 1) {
tooth++;
if (tooth == 48) {
  tooth = 0;
  }

Cycles through the array one at a time.

Code: Select all

int math = 1;
int halfdone = 1;
int done = 1;

Are just flags to dictate the order of each if statement.