C example of using the USCI as a 9600 baud UART to communicate with the HC-06 bluetooth module for the MSP430F5529

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/* This program asks you for the password, and then tells

* you if you typed it right.  You need to set the bluetooth
* terminal to send /n, or /n at the end of a send.  The app
* I used on my Android phone is from:
* https://github.com/Sash0k/bluetooth-spp-terminal
*
* Originally from the textbook, modified for the MSP430F5529
* by Rob Frohne 7/21/2015.
*
* The HC-06 bluetoooth module I used to test this is connected
* to the +5V and GND on the launchpad.  The RXD of the HC-06 is
* connected to P3.3 and TXD of the HC-06 is connected to P3.4.
*
* Note the changes to the interrupt as compared to the G2 Launchpad.
*/

1. include <msp430.h>
2. define RedLed BIT0
3. define GreenLed BIT7

char password[] = "12345"; //The Password char enter[] = "Enter Your Password\r\n"; char correct[] = "Your password is correct\r\n"; char incorrect[] = "Your password is incorrect\r\n"; char reenter[] = "Please re-enter your password\r\n"; char input[100]; int RXByteCtr = 0; int cnt = 0; int inputlength,passwordlength; int difference; void transmit(char *str); int compare(char *strin, char *strpass); int arraylength(char *str);

/*

* main.c
*/

void main(void) { WDTCTL = WDTPW|WDTHOLD; /* BCSCTL1 = CALBC1_1MHZ;//Adjust the clock DCOCTL = CALDCO_1MHZ;*/ P1DIR = RedLed; //Make P1.0 an output so we can use the red LED P4DIR = GreenLed; //Make P4.7 an output so we can use the red LED P1OUT &= ~RedLed; //Clear the red LED P4OUT &= ~GreenLed; //Clear the green LED

P3SEL = BIT3+BIT4; // P3.4,5 = USCI_A0 TXD/RXD UCA0CTL1 |= UCSWRST; // **Put state machine in reset** UCA0CTL1 |= UCSSEL_2; // SMCLK UCA0BR0 = 6; // 1MHz 9600 (see User's Guide) UCA0BR1 = 0; // 1MHz 9600 UCA0MCTL = UCBRS_0 + UCBRF_13 + UCOS16; // Modln UCBRSx=0, UCBRFx=0, // over sampling UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine** transmit(enter); UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt _enable_interrupts(); while(1){ if(cnt == 1){ //Check if cnt is 1 inputlength = arraylength(input); //Get your input length passwordlength = arraylength(password); //Get your password length {difference = compare(input,password);} //Compare the received password with your password if(difference == 0){ //Check if they match {transmit(correct);} //If they match, transmit correct string P1OUT &= ~RedLed; P4OUT |= GreenLed; //Turn on the green LED __delay_cycles(5000000); //Wait for 5 seconds P4OUT &= ~GreenLed; WDTCTL = WDT_MRST_0_064; // Turns off the LED too. //Reset the system } else {//If they do not match {transmit(incorrect);} //Transmit incorrect string P1OUT = RedLed; //Turn on the red LED __delay_cycles(2000000); //Wait for 2 seconds P4OUT &= ~RedLed; //Turn off the red LED {transmit(reenter);} }//Transmit reenter string cnt = 0; //Reset cnt RXByteCtr = 0; }}//Reset Receive Byte counter }

//USCI A receiver interrupt // The stuff immediately below is to make it compatible with GCC, TI or IAR

1. if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
2. pragma vector=USCI_A0_VECTOR

__interrupt void USCI_A0_ISR(void)

1. elif defined(__GNUC__)

void __attribute__ ((interrupt(USCI_A0_VECTOR))) USCI_A0_ISR (void)

1. else
2. error Compiler not supported!
3. endif

{ //Check if the UCA0RXBUF is different from 0x0A //(Enter key from keyboard) if(UCA0RXBUF != 0x0A) input[RXByteCtr++] = UCA0RXBUF; //If it is, load received character //to current input string element else{cnt = 1; //If it is not, set cnt input[RXByteCtr] = 0; } //Add null character at the end of input string } void transmit(char *str){ while(*str != 0){//Do this during current element is not //equal to null character while (!(UCTXIFG&UCA0IFG)); //Ensure that transmit interrupt flag is set UCA0TXBUF = *str++; //Load UCA0TXBUF with current string element }//then go to the next element }

int max(int a, int b){ if(a>b) return a; else return b; } // Find the max between two numbers.

int compare(char *strin, char *strpass){ int i=0; int result = 0;//Clear result int len = max((passwordlength),inputlength); for(i=0;i<len;i++) { result = result + abs((*strin++)-(*strpass++)); } // abs used to make sure differences don't cancel return result; }//Return result value

int arraylength(char *str){ int length = 0; //Clear length while(*str != 0){ //Until null character is reached str++; //Increase array address length++; } //Increase length value return length; }//Return length value

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