MSP430g2553 Launchpad UART from Energia serial monitor

Gabe Mateski

Other Parts Discussed in Thread: ENERGIA

Hi.

I'm trying to set up some basic UART code to process commands from the Energia serial monitor. Right now I just have the basic initialization code and the interrupt, and I want to turn on the red LED on the launchpad when I enter the interrupt so I know that the command is being received. It doesn't seem to be entering the interrupt whenever I type something into the serial monitor. I have the serial monitor set for 9600 baud, and I think that's what I have in my code, but I could be wrong. My code is posted below. Any help would be appreciated. Thanks!

#include <msp430g2553.h>
#include <legacymsp430.h>
#include <io.h>
#include <stdlib.h>
#include <stdint.h>

#pragma vector= USCIAB0RX_VECTOR
__interrupt void USCIAB0RX_ISR(void){
  
  digitalWrite(RED_LED, HIGH);
}

void uart_init(){
  
  UCA0CTL1 |= UCSWRST;
  UCA0CTL1 |= UCSSEL_2;                      //SMCLK
  UCA0BR0 = 65;                              //9600 BAUD
  UCA0BR1 = 3;                               //9600 BAUD 
  UCA0MCTL |= UCBRS_2;                       //Modulation
  IE2 |= UCA0RXIE;                           //Enable interrupts
  UCA0CTL1 &= ~UCSWRST;
}

void clock_init(){
  
  WDTCTL = WDTPW + WDTHOLD;                  // Stop WDT
  BCSCTL1 = CALBC1_16MHZ & 0xBF;
  BCSCTL2 = 0x00;                            
  BCSCTL3 = 0x0C;
        
  DCOCTL = CALDCO_16MHZ;                     //DCO set to 16MHz
}

int main(void){
  
  clock_init();
  uart_init();
  __bis_SR_register(GIE);                    //Enable interrupts
  
  pinMode(RED_LED, OUTPUT);
  digitalWrite(RED_LED, LOW);
  
  while(1){
    
  }
}

over 10 years ago

0 Ryan Brown1 over 10 years ago

TI__Guru**** 212077 points

Hi Gabe,

Please see the fix below:

#include <msp430g2553.h>
#include <legacymsp430.h>
#include <io.h>
#include <stdlib.h>
#include <stdint.h>

#pragma vector= USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void){
  
  digitalWrite(RED_LED, HIGH);
}

void uart_init(){
  
  P1SEL = BIT1 + BIT2 ;                     // P1.1 = RXD, P1.2=TXD
  P1SEL2 = BIT1 + BIT2 ;                    // P1.1 = RXD, P1.2=TXD
  
  UCA0CTL1 |= UCSWRST;
  UCA0CTL1 |= UCSSEL_2;                      //SMCLK
  UCA0BR0 = 82;                              //9600 BAUD
  UCA0BR1 = 6;                               //9600 BAUD 
  UCA0MCTL |= UCBRS_2;                       //Modulation
  UCA0CTL1 &= ~UCSWRST;
  IE2 |= UCA0RXIE;                           //Enable interrupts

}

void clock_init(){
  
  WDTCTL = WDTPW + WDTHOLD;                  // Stop WDT
  if (CALBC1_16MHZ==0xFF)					// If calibration constant erased
  {											
    while(1);                               // do not load, trap CPU!!	
  }
  BCSCTL1 = CALBC1_16MHZ;        
  DCOCTL = CALDCO_16MHZ;                     //DCO set to 16MHz
}

int main(void){
  
  clock_init();
  uart_init();
  __bis_SR_register(GIE);                    //Enable interrupts
  
  pinMode(RED_LED, OUTPUT);
  digitalWrite(RED_LED, LOW);
  
  while(1){
    
  }
}

Be sure to set the LaunchPad RXD and TXD headers to the horizontal "HW UART" position to correctly communicate using backchannel UART

Regards, Ryan

0 Gabe Mateski over 10 years ago in reply to Ryan Brown1

Prodigy 90 points

That did the trick. Thanks!

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MSP430g2553 Launchpad UART from Energia serial monitor