TX command code & RX respond code of module via serial com

mr_hacker90 · January 15, 2013, 8:54am

hi everyone. i have a question here. i need to sent 8 bytes command code to a fingerprint reader. and then, read the 6 bytes respond code of the reader. sending & reading the code is via serial (RX & TX). i already made the code. but, it is not working. i just want to ask your opinion what's wrong with my code here. seems that the TX & RX LED even not light up when i start the program. thank you.

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8,9,4,5,6,7);

byte addFingerPrint[] = {0x4D, 0x58, 0x10, 0x03, 0x40, 0x00, 0x00, 0xF8};
byte respond = 0;

void setup() {
  // initialize serial:
  Serial.begin(57600);
  
  // set up the LCD's number of columns and rows: 
  lcd.begin(8, 2);

  displayLCD();
  
  addFinger();
  
  correctRespond();
}

void displayLCD(){
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 0);
  // Print a message to the LCD.
  lcd.print("Reader");
}

void addFinger(){
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print("Add");

  // print the string when a newline arrives:
  Serial.write(addFingerPrint, sizeof(addFingerPrint));
  
  delay(1000);
}

void correctRespond() {
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print("Cor");
  
  if (Serial.available()) {
  // read the most recent byte
  respond = Serial.read();
  }
  
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  // print the correct respond code of the reader (0x4D, 0x58, 0x30, 0x01, 0x01, 0xD7)
  lcd.print("Cor=");
  lcd.print(respond, HEX);
  
  delay(1000);
}

void loop() {
}

system · January 15, 2013, 9:54am

How many characters of the reply are you reading? How long are you waiting for the reply?

quertyn · January 15, 2013, 10:54am

Hi,

First thing in your code, in correctRespond function you should poll until the fingerprint reader sent back a response, just in case correctRespond is called too early, before the fingerprint reader had enough time to respond. You can do something like this:

void correctRespond() {
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print("Cor");
  
  while(Serial.available() == 0){
    delay(10);
  }

  // read the most recent byte
  respond = Serial.read();

  
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  // print the correct respond code of the reader (0x4D, 0x58, 0x30, 0x01, 0x01, 0xD7)
  lcd.print("Cor=");
  lcd.print(respond, HEX);
  
  delay(1000);
}

system · January 15, 2013, 11:11am

  while(Serial.available() == 0){
    delay(10);
  }

Can you describe the exact purpose for the delay()? Does it matter whether the while loop iterates 10 times in 100 milliseconds, or 10,000,000?

If you know (or think/hope) that the response is going to be 6 bytes, wait for 6,

Then, of course, you still need to read all 6 of them.

mr_hacker90 · January 15, 2013, 12:07pm

respond = Serial.read();

this command i believe just read a byte / char. if i want to put a loop, which read 6 bytes. how i'm gonna make it. of course it need a for loop. but, how i gonna integrate the counter with the serial read.

for (int n=0; n<7; n++) {
{

system · January 15, 2013, 12:21pm

this command i believe just read a byte / char. if i want to put a loop, which read 6 bytes. how i'm gonna make it. of course it need a for loop. but, how i gonna integrate the counter with the serial read.

That for loop will iterate while n = 0, 1, 2, 3, 4, 5, and 6. That's 7 iterations, not 6.

byte reply[6];
for(byte n=0; n<6; n++)
{
   while(Serial.available() == 0) {}; // Wait for a byte
   reply[n] = Serial.read();
}
// Now, reply contains all 6 bytes

system · January 15, 2013, 12:37pm

understand. now i'm using x-ctu serial terminal.

You've removed the fingerprint reader?

but the x-ctu hyperterminal shows FF

Also known as -1 (no data).

X-CTU is fine for talking to XBees. Other than that, I find it useless.

mr_hacker90 · January 15, 2013, 12:40pm

nono.. it's correct. i'm mistaken configure the baud. is shows all the 8 bytes. correctly. i just want to check whether it's write the 8 bytes. this tips is being told by my lecturer. to check the bytes of the TX pin.

mr_hacker90 · January 15, 2013, 12:53pm

the uno transmit 8 bytes. if it managed to receive respond code, how i'm gonna compare it either right or wrong? can i just make it like this? correct respond is 6 bytes while wrong respond is 7 bytes.

for(byte n=0; n<7; n++)
  {
    while(Serial.available() == 0) {}; // Wait for a byte
    respond[n] = Serial.read();
  }
  
  // Now, reply contains all 6 bytes
  
    if (respond== "0x4D + 0x58 + 0x30 + 0x01 + 0x01 + 0xD7"){
        // set the cursor to column 0, line 1
        lcd.setCursor(0, 1);
        // print the correct respond
        lcd.print("Correct Respond");
        }
      
    else if(respond== "0x4D + 0x58 + 0x30 + 0x02 + 0x40 + 0x35 + 0x4C"){
        // set the cursor to column 0, line 1
        lcd.setCursor(0, 1);
        // print the wrong respond
        lcd.print("Wrong Resp");
        }

system · January 15, 2013, 1:12pm

Hello? Are you listening?

for(byte n=0; n<7; n++)

will iterate SEVEN times, not 6.

    if (respond== "0x4D + 0x58 + 0x30 + 0x01 + 0x01 + 0xD7"){

The address of an array of bytes will NEVER equal the address of a literal string.

You can have another array,

byte correct[] = {0x4D, 0x58, 0x30, 0x01, 0x01, 0xD7};

Then, you can use memcmp() to compare the arrays. But, you can't just make up stuff.

mr_hacker90 · January 15, 2013, 1:21pm

memcmp()? by the way, it is quite confusing. because the correct command respond is 6 bytes but wrong command respond is 7 bytes. that is the reason why i put 7 sir.

byte correctRespond[] = {0x4D, 0x58, 0x30, 0x01, 0x01, 0xD7};
byte wrongrespond[] = {0x4D, 0x58, 0x30, 0x02, 0x40, 0x35, 0x4C);

the fingerprint reader respond correct or wrong not in same byte length.

system · January 15, 2013, 1:28pm

by the way, it is quite confusing. because the correct command respond is 6 bytes but wrong command respond is 7 bytes.

Perhaps you need to post a link to the fingerprint reader. It does not make sense to return two different length arrays when the finger print is valid and is not valid.

mr_hacker90 · January 15, 2013, 1:34pm

PaulS:
Perhaps you need to post a link to the fingerprint reader. It does not make sense to return two different length arrays when the finger print is valid and is not valid.

if u think that way, i also think the same. nevermind. but how i'm gonna post the link to the reader. i need to compare lots of byte array. memcmp()

system · January 15, 2013, 1:42pm

but how i'm gonna post the link to the reader.

Use the 3rd icon on the bottom row. Paste the URL after clicking the icon.

mr_hacker90 · January 15, 2013, 1:48pm

PaulS:

but how i'm gonna post the link to the reader.

Use the 3rd icon on the bottom row. Paste the URL after clicking the icon.

i'm sorry. i don't understand sir.

system · January 15, 2013, 2:03pm

Where did you get the fingerprint reader you are trying to talk to? We have to know something about it in order to help you.

mr_hacker90 · January 15, 2013, 2:07pm

my fingerprint? this is my fingerprint that i bought. at first i juz thought simple RX & TX. i never thought that it quite difficult to a beginner like me. SN-FPR-SM630. thank you mr pauls.

mr_hacker90 · January 15, 2013, 3:17pm

i've studied a little bit. thank you to u sir. finally understand it a little bit. but, too bad. i don't bring the reader to my house. i left it at my hostel. at least i know the basic function. but, i'm not sure either this is the correct way to compare it. but, i know the basic operation by the way. i just not sure about the

m = memcmp(operationSuccess, operation, sizeof(operationSuccess));

by the way, thank you so much sir. at least from zero. i got half of it on what you told me. i wish i could got all of it. but i know, i need to study more. thank you coz taught me.

byte operationSuccess[] = {0x4D, 0x58, 0x30, 0x02, 0x40, 0x31, 0x48};
byte operation[7],m;

void operationSuccesful() {
  // Now, reply contains all 7 bytes
  for(byte n=0; n<7; n++)
  {
    while(Serial.available() == 0) {}; // Wait for a byte
    operation[n] = Serial.read();
    
    m = memcmp(operationSuccess, operation, sizeof(operationSuccess));
    
    if (m>0) {
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 0);
      // print the number of seconds since reset:
      lcd.print("Operation Failed");
      }
      
    else if (m<0) {
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 0);
      // print the number of seconds since reset:
      lcd.print("Operation Failed");
      }

    
    else {
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 0);
      // print the number of seconds since reset:
      lcd.print("Operation Success");
      }
  }
}

mr_hacker90 · January 16, 2013, 8:11am

hello everyone. i currently make try to make a simple project. uno with fingerprint reader. as startup i try to add fingerprint.

at first. i try run the fingerprint reader + uno with X-CTU only. i use the terminal of the X-CTU. i sent the command code of the reader. and the reader reply with correct respond code & success operation code.
as u can see in the picture, the first 8 bytes {0x4D, 0x58, 0x10, 0x03, 0x40, 0x00, 0x00, 0xF8} is the command code for add fingerprint. then the reader reply 6 bytes correct respond code, {0x4D, 0x58, 0x30, 0x01, 0x01, 0xD7}. later the reader reply 7 bytes success operation code, {0x4D, 0x58, 0x30, 0x02, 0x40, 0x31, 0x48}.

then, i try make the program. so that it follow exactly what the reader respond as i tested above. i manage to make the code. by using X-CTU. i key the respond code, the arduino program able to detect the 6 bytes of the correct respond code & 7 bytes of success operation.

however, when i try to combine them both, it doesn't being to be happen. the arduino uno transmit the command code. but, the reader doesn't respond to that code. i believe there is a problem with my code. but, i don't have any idea where's the problem. with all, regards.

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8,9,4,5,6,7);

byte addFingerPrint[] = {0x4D, 0x58, 0x10, 0x03, 0x40, 0x00, 0x00, 0xF8}; // 8 bytes
byte respondCorrect[] = {0x4D, 0x58, 0x30, 0x01, 0x01, 0xD7}; // 6 bytes

byte operationSuccess[] = {0x4D, 0x58, 0x30, 0x02, 0x40, 0x31, 0x48}; // 7 bytes
byte timeOut[] = {0x4D, 0x58, 0x30, 0x02, 0x40, 0x33, 0x4A}; // 7 bytes
byte processFailure[] = {0x4D, 0x58, 0x30, 0x02, 0x40, 0x34, 0x4B}; // 7 bytes
byte parameterError [] = {0x4D, 0x58, 0x30, 0x02, 0x40, 0x35, 0x4C}; // 7 bytes
byte respond[6],operation[7],a,b,c,d;

void setup() {
  // initialize serial:
  Serial.begin(57600);
  
  // set up the LCD's number of columns and rows: 
  lcd.begin(8, 2);

  displayLCD();
  
  addFinger();
  
  correctRespond();
  
  operationSuccesful();
}

void displayLCD(){
  // set the cursor to column 0, line 0
  lcd.setCursor(0, 0);
  // Print a message to the LCD.
  lcd.print("Fingerprint Reader");
}

void addFinger(){
  // set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  // Print a message to the LCD.
  lcd.print("Add Fingerprint");

  // write the 8bytes array of the command code
  Serial.write(addFingerPrint, sizeof(addFingerPrint));
  //delay(2000);
}

void correctRespond() {
  // Now, reply contains all 6 bytes
  for(byte n=0; n<6; n++)
  {
    while(Serial.available() == 0) {}; // Wait for a byte
    respond[n] = Serial.read();
    
    a = memcmp(respondCorrect, respond, sizeof(respondCorrect));

    if (a>0) {
      // set the cursor to column 0, line 0
      lcd.setCursor(0, 0);
      // Print a message to the LCD.
      lcd.print("Wrong   ");
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 1);
      // Print a message to the LCD.
      lcd.print("Respond ");
      }
      
    else if (a<0) {
      // set the cursor to column 0, line 0
      lcd.setCursor(0, 0);
      // Print a message to the LCD.
      lcd.print("Wrong   ");
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 1);
      // Print a message to the LCD.
      lcd.print("Respond ");
      }
    
    else {
      // set the cursor to column 0, line 0
      lcd.setCursor(0, 0);
      // Print a message to the LCD.
      lcd.print("Correct ");
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 1);
      // Print a message to the LCD.
      lcd.print("Respond ");
      }
  }
  delay(2000);
}

void operationSuccesful() {
  // Now, reply contains all 7 bytes
  for(byte n=0; n<7; n++)
  {
    while(Serial.available() == 0) {}; // Wait for a byte
    operation[n] = Serial.read();
    
    b = memcmp(operationSuccess, operation, sizeof(operationSuccess));
    
    if (b==0) {
      // set the cursor to column 0, line 0
      lcd.setCursor(0, 0);
      // Print a message to the LCD.
      lcd.print("Operation");
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 1);
      // Print a message to the LCD.
      lcd.print("Success ");
      }

    else {
      c = memcmp(processFailure, operation, sizeof(processFailure));
      
      if (c==0) {
        // set the cursor to column 0, line 0
        lcd.setCursor(0, 0);
        // Print a message to the LCD.
        lcd.print("Process ");
        // set the cursor to column 0, line 1
        lcd.setCursor(0, 1);
        // Print a message to the LCD.
        lcd.print("Failure ");
        }
      
      else  {
        d = memcmp(parameterError, operation, sizeof(parameterError));
        
        if (d==0) {
          // set the cursor to column 0, line 0
          lcd.setCursor(0, 0);
          // Print a message to the LCD.
          lcd.print("Parameter");
          // set the cursor to column 0, line 1
          lcd.setCursor(0, 1);
          // Print a message to the LCD.
          lcd.print("Error   ");
          }
        
        else {
          // set the cursor to column 0, line 0
          lcd.setCursor(0, 0);
          // Print a message to the LCD.
          lcd.print("Time    ");
          // set the cursor to column 0, line 1
          lcd.setCursor(0, 1);
          // Print a message to the LCD.
          lcd.print("Out     ");
        }
      }
    }
  } 
  delay(2000);
}

void loop() {
}

system · January 16, 2013, 10:21am

Why are you starting a new thread on the same topic?

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TX command code & RX respond code of module via serial com

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