How to split ECU string data on Arduino?

Question

I have a question for splitting engine control system string data from a serial port. The communication protocol description is below.

Example: To retrieve the data displayed on the LCD screen of the FADEC. If the command is RSD, then the output would be:

**C7h 2Ch 52h 53h 44h 2Ch 0Dh**

C7h -> Sync
2Ch -> “,” Separator
52h -> “R”
53h -> “S”
44h -> “D”
2Ch -> “,” Separator
0Dh -> CR, last byte.

The ECU will return two strings. The first, a copy of the command received, followed by the data requested. In the above example, it will return:

**C7h, RSD, 0Dh**
C7h -> Sync byte
2Ch -> “,” Separator

Payload in ASCII “TrimLow EGT 20CRpm 50.000Pw=124”
2Ch -> “,” Separator
0Dh -> CR, last byte.

I read all the data on the screen in string format. When I send RCV to the ECU, it will return RPM, temperature, pump voltage, battery voltage and throttle according to the above form.

Xicoy description: ( Command, Meaning, Payload)

RCV Read Current Values RPM, EGT in ºC, Pump Power, Voltage of Battery,Throttle %

    byte veri[]= { 0xC7, 0x2C, 0x52, 0x43, 0x56, 0x2C, 0x0D }; // for RCV

And datasheet (page 5-6-7): http://www.xicoy.com/SerialAdapt1_0.pdf

#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); // RX, TX
int i=0;
byte veri[]= { 0xC7, 0x2C, 0x52, 0x43, 0x56, 0x2C, 0x0D }; // RCV
int myTimeout = 100;

void setup() {
  Serial.begin(9600);
  mySerial.begin(9600);
  mySerial.setTimeout(myTimeout);
}

void loop() {
  Serial.println(mySerial.readString());
  for(i=0;i<7;i++)
  {
    mySerial.write(veri[i]);
  }
}

How can I separate RPM, EGT °C, pump voltage, battery voltage and throttle % in the data packet that is coming back from the ECU? After the discrimination process, I will send it to LabView via the second serial port. The RPM values can be 6 digits (approx. 120000 RPM) and the exhaust gas temperature is 3 digits (EGT 800 °C), the figures may be missing because all are zero except throttle value. Can you share a sample? Thanks.

Picture:

Does arduino have CSV parsing library? I am not very much familiar with Arduinos. — Gaurav Pathak, Jul 10 '17 at 11:25
A normal `sscanf` could work. Since Arduino uses a variant of C++ there might be other ways to get the substrings. — Some programmer dude, Jul 10 '17 at 11:26

score -1 · Accepted Answer · answered Jul 10 '17 at 14:21

Also answer is ;

#include <SoftwareSerial.h>

SoftwareSerial mySerial(10, 11); // RX, TX

int i=0;
byte veri[]= { 0xC7, 0x2C, 0x52, 0x43, 0x56, 0x2C, 0x0D }; // RCV
int myTimeout = 10;  
String veri2[]={};
void setup() {
Serial.begin(9600);
while (!Serial) {
}
analogWrite(5,250);
mySerial.begin(9600);
mySerial.setTimeout(myTimeout);
}

void loop() { // run over and over

for(i=0;i<7;i++)
{
mySerial.write(veri[i]);
}

String split = mySerial.readString();
String word3 = getValue(split, ',',0);
Serial.println(word3);
for(i=0;i<7;i++)
{
mySerial.write(veri[i]);
}

String  split2 = mySerial.readString();
String word4= getValue(split2, ',',1);
Serial.println(word4);
 /*
split = mySerial.readString();
word3 = getValue(split, ',',2);
Serial.println(word3);
split = mySerial.readString();
word3 = getValue(split, ',',3);
Serial.println(word3);
split = mySerial.readString();
word3 = getValue(split, ',',4);
Serial.println(word3);
split = mySerial.readString();
word3 = getValue(split, ',',5);
Serial.println(word3);
split = mySerial.readString();
word3 = getValue(split, ',',6);
Serial.println(word3);
split = mySerial.readString();
word3 = getValue(split, ',',7);
Serial.println(word3);
}

*/

 String getValue(String data, char separator, int index)
 {
 int found = 0;
 int strIndex[] = {0, -1};
 int maxIndex = data.length()-1;

 for(int i=0; i<=maxIndex && found<=index; i++){
 if(data.charAt(i)==separator || i==maxIndex){
    found++;
    strIndex[0] = strIndex[1]+1;
    strIndex[1] = (i == maxIndex) ? i+1 : i;
 }
 }

 return found>index ? data.substring(strIndex[0], strIndex[1]) : "";
 }

How to split ECU string data on Arduino?

1 Answers1