MSP430FR2355: MSP430 LaunchPad - Code Composer Studio breakpoint jumping to different line.

Aaron Davis

Part Number: MSP430FR2355

Tool/software:

I wrote a quick-and-dirty program for my MSP430 LaunchPad to test if a sensor would detect a magnet but I'm having trouble debugging it because CCS keeps moving the breakpoint I put inside an if statement. Relevant section of code:

Fullscreen

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
    // Configure ports
    P1DIR |= BIT0;          // Config P1.0 (LED1) as output
    P1OUT &= ~BIT0;         // Clear LED1 to start
    P1DIR &= ~BIT5;         // Config P1.5 input
    P1REN |= BIT5;          // Enable resistor
    P1OUT |= BIT5;          // Make pull-up resistor
    PM5CTL0 &= ~LOCKLPM5;
    while (1) {
        if (P1IN & BIT5 == 0) {
            P1OUT |= BIT0;
        }
        else P1OUT &= ~BIT0;
    }
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    // Configure ports
    P1DIR |= BIT0;          // Config P1.0 (LED1) as output
    P1OUT &= ~BIT0;         // Clear LED1 to start
    P1DIR &= ~BIT5;         // Config P1.5 input
    P1REN |= BIT5;          // Enable resistor
    P1OUT |= BIT5;          // Make pull-up resistor

    PM5CTL0 &= ~LOCKLPM5;

    while (1) {
        if (P1IN & BIT5 == 0) {
            P1OUT |= BIT0;
        }
        else P1OUT &= ~BIT0;
    }

I've tried several different permutations of trying to get the breakpoint to be inside the if statement, but it keeps jumping to the else statement for no apparent reason.

5 months ago

0 JD Crutchfield 5 months ago

TI__Mastermind 28955 points

Hey Aaron,

Are you saying the issue is a code issue or a breakpoint issue?

Can you try putting "__no_operation();" in your if statement code and then break pointing at it?

Thanks,

0 Aaron Davis 5 months ago in reply to JD Crutchfield

Prodigy 51 points

It's an issue with the breakpoint, not my code: I added __no_operation(); between lines 11 and 12 just now, and the breakpoint still jumped straight to the else line when I compiled.

0 Seth Jackson 5 months ago in reply to Aaron Davis

Expert 1990 points

Did you see the accepted answer in the thread you linked from about turning off compiler optimization?

+1 Bruce McKenney 5 months ago

Guru 95545 points

> if (P1IN & BIT5 == 0) {

Due to operator precedence, this executes as "if(P1IN & 0)", i.e. it's always false, so the compiler doesn't generate any code for that clause. Try instead:

> if ((P1IN & BIT5 )== 0) {

0 JD Crutchfield 5 months ago in reply to Bruce McKenney

TI__Mastermind 28955 points

Ah, good catch Bruce!

0 Aaron Davis 5 months ago in reply to Bruce McKenney

Prodigy 51 points

And le facepalm. That solved it right there, and that means maybe the sensor was working after all and I just did a dumb.

ETA: Yep, the sensor (A3144 Hall effect switch) works fine, though it's still not sensitive enough to be useful in the application: the LED comes on, it just requires the object to be too close to the Hall effect sensor and in the correct orientation.

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

MSP430FR2355: MSP430 LaunchPad - Code Composer Studio breakpoint jumping to different line.