UART1_Read_Text() issue

Question

I am using PICKit3, MikroC PRO for PIC v6.0.0, PIC18F45 @ 8MHz and RN-42 bluetooth module. I'm connecting to the RN-42 module both from the laptop and from my Android app and i am sending a password. The weird thing is that the PIC sometimes says that the password is correct, but sometimes it doesn't. I am sending the same string. While testing, it happened to not accept the pass only the first time and all other attempts were accepted. The UART baud rate is 9600 set on both the PIC and the RN-42. RTS & CTS on the RN-42 are not connected.

I tried also:

char password[] = "abc";
char password[4] = "abc";
char password[5] = "abc\0";
char *password = "abc\0";

strcmp(input, "\0"); after the UART1_Read_Text(input, "|", MAX_UART_RX_CHARACTERS);

But it's the same... What could be the problem, is it in my code or is it possible to be and issue inside the MikroC functions?

void authenticate() {
     char input[MAX_UART_RX_CHARACTERS + 1] = "";
     char password[] = "abc\0";
     unsigned char ready = 0;

     Delay_ms(500);
     UART1_Write_Text("TRobot\n");

     while (connected && !ready) {
           if (UART1_Data_Ready()) {
              TMR0ON_bit = 0;
              time_out = 0;
              UART1_Read_Text(input, "|", MAX_UART_RX_CHARACTERS);

              if (strcmp(input, password) == 0) {
                 UART1_Write('y');
                 serve();
              } else {
                 UART1_Write('n');
                 disconnect();
              }

              ready = 1;
           }

           if (time_out) {
              disconnect();
           }
     }
}

UARTx_Read_Text() Prototype:

void UARTx_Read_Text(char *Output, char *Delimiter, char Attempts);

UARTx_Read_Text() Description:

Reads characters received via UART until the delimiter sequence is detected. The read sequence is stored in the parameter output; delimiter sequence is stored in the parameter delimiter.

This is a blocking call: the delimiter sequence is expected, otherwise the procedure exits (if the delimiter is not found).

Parameters :

Output: received text Delimiter: sequence of characters that identifies the end of a received string Attempts: defines number of received characters in which Delimiter sequence is expected. If Attempts is set to 255, this routine will continuously try to detect the Delimiter sequence.

Example:

Read text until the sequence “OK” is received, and send back what’s been received:

UART1_Init(4800);                         // initialize UART1 module
Delay_ms(100);

while (1) {
  if (UART1_Data_Ready() == 1) {          // if data is received 
    UART1_Read_Text(output, "OK", 10);    // reads text until 'OK' is found
    UART1_Write_Text(output);             // sends back text 
 }
}

Answer 1

you can do a strlen(input) to see if there are invisible symbols behind or compare the arrays value by value to see where the difference is.

Also strncmp(input, password, strlen(password)); might help. This would ignore all symbols behind the length of password which will make abcd a valid password, so be afraid of this.