Adding ALDL scanner support to MPGuino

[toc]

Set it to 100 or 200. Won't matter much.

#define MAX_WAIT_TIME 100


int fetch_data(byte cmd) {
int dat[3];
int temp;
int i;
Serial.write(cmd);
starttime = millis();
while ((Serial.available()<2) && ( (millis() - starttime) < MAX_WAIT_TIME) ) {
//do nothing
}
if (Serial.available()<2) {
wireless.print("Error - 2 Bytes not found - We did get:");
wireless.println(Serial.read(), HEX);
Serial.flush();
} else {
i = 0;
delay(10);
while (Serial.available() > 0) {

temp = Serial.read();
wireless.print("Dat ");
wireless.print(i);
wireless.print(": ");
wireless.print(temp, HEX);
dat[i] = temp;
i++;
//dat[0] should be the cmd we sent
//dat[1] should be the result of the cmd.
}
Serial.flush();
return dat[1];
}

}

void loop()
{
int temp_val;
int temp_real_val;
wireless.println("Testing at 1920bps");
wireless.print("RPM: Result:");
temp_val = fetch_data(0x21);
temp_real_val = temp_val * 31.25;
wireless.print(temp_val, HEX);
wireless.print("|RPM Val: ");
wireless.println(temp_real_val);

You should be able to fetch the HEX value - 0x21, and convert to DEC then multiply by 31.25.

Looks like I missed the convert to dec perhaps..


If you are still having problems, give us a look at the parameter you are requesting (RPM is a good one), tell us the hex value of the response, and what value you are getting..

[oldskool]

Thanks again TOC,

I will give the result as soon as possible TOC. By the way, i still do not know why in MMCd source code using the function below to get the value. Have a look at the source code:

// Engine speed, 0..8000 rpm
// 31.25 * x
Int16 f_ERPM(UInt8 d, Char *s) {
	Int32 v = 2048000L * d;
	return StrPrintF(s, "%ldrpm", v >> 16);
}

Where does the value 2048000L is coming. If I'm not wrong the 'L" is use for formatting the data value

Arduino IntegerConstants
arduino.cc/en/Reference/IntegerConstants

U & L formatters

By default, an integer constant is treated as an int with the attendant limitations in values. To specify an integer constant with another data type, follow it with:

a 'u' or 'U' to force the constant into an unsigned data format. Example: 33u
a 'l' or 'L' to force the constant into a long data format. Example: 100000L
a 'ul' or 'UL' to force the constant into an unsigned long constant. Example: 32767u

[oldskool]

Ok i get the clue now.

Since the maximum RPM was set to 8000, and the RPM range value is 0-255.
Therefore 8000/256 = 31.25

But still wondering about 31.25*8000=2048000

[oldskool]

Here is the 1G DSM, Mitsubishi 4g93,4g92,4g91 ecu protocol. I get it from the web archive of http://www.syndicate.evilsoft.org/pr..._Protocol.html

Sensor	 	    |	Address	   |	Data Min	 |	Data Max     | 		Function 	|	Sample
=============================================================================================================================
Accel Enrichment 	0x1D 		0x01 == 0% 		0xFF == 100% 		y = 100(x/255) 		%
Coolant Temp 		0x07 		0x01 == 307deg F 	0xFF == -62deg F 	y = -1.45x + 308 	deg F
Engine Speed 		0x21 		0x01 == 31 		0xFF == 7969 		y = 31.25x 		rpm
Fuel Trim High 		0x0E 		0x01 == 1% 		0xFF == 199% 		y = .78x 		%
Fuel Trim Low 		0x0C 		0x01 == 1% 		0xFF == 199% 		y = .78x 		%
Fuel Trim Middle 	0x0D 		0x01 == 1% 		0xFF == 199% 		y = .78x 		%
Injector Pulse Width 	0x29 		0x01 == .256ms 		0xFF == 65.3ms 		y = .256x 		ms
Oxygen Feedback Trim 	0x0F 		0x01 == 1% 		0xFF == 199% 		y = .78x 		%
Oxygen Sensor 		0x13 		0x01 == .02v 		0xFF == 4.98v 		y = .0195x 		v
Throttle Position 	0x17 		0x01 == 0% 		0xFF == 100% 		y = 100(x/255) 		%
Air Flow Hz 		0x1A 		0x01 == 6Hz 		0xFF == 1606Hz 		y = 6.29x 		Hz
Air Temperature 	0x3A 		0x01 == 356deg F 	0xFF == -74deg F 	y = -1.69x + 358 	deg F
Air Volume 		0x2C 		0x01 == 1 		0xFF == 255 		y = x 	
Barometer 		0x15 		0x01 == 0bar 		0xFF == 1.24bar 	y = .00486x 		bar
ISC Steps 		0x16 		0x01 == 1 		0xFF == 255 		y = x 	
Knock Sum 		0x26 		0x01 == 1 		0xFF == 255 		y = x 	
Timing Advance 		0x06 		0x01 == -9 deg 		0xFF == 245 deg 	y = x - 10 		deg
Battery 		0x14 		0x01 == 0.1v 		0xFF == 18.7v 		y = .0733x 		v
EGR Temperature 	0x12 		0x01 == 595deg F 	0xFF == -94deg F 	y = -2.7x + 597.7	deg F 
TDC 			0x02 		0x04 (inverted) 			
Power Steering 		0x02 		0x08 (inverted) 			
AC Switch 		0x02 		0x10 (inverted) 			
Park/Neutral 		0x02 		0x20 (inverted) 			
Idle Switch 		0x02 		0x80 (inverted) 			
AC Clutch 		0x00 		0x20 (inverted)

So i made a mistake on the last post calculation:
The correct formula for RPM (refer to calculation table)
7969/255 = 31.25 for each incremental number of 255

[toc]

I'm not sure I see a problem ?
Are you getting data OK?

[oldskool]

Hi Toc,

I still don't have enough time to check the data because 2 of my sons were admitted in hospital.
Hopefully i can check it on this week. I will get you if all data still incorrect.

Thanks again...