MSP430G2553: Switch interupt

MUKHRAMUDDIN MOHAMMED

Part Number: MSP430G2553

Hello,

I am trying to program MSP430g2553 MCU to do something when i press the tactile (Internal interrupt) switch for 2 - 3 seconds continuously. Can you please help me how can i program the interrupt code.

Code :

# pragma vector=PORT2_VECTOR
__interrupt void port_2(void)
{

j_delay++;

P2IFG &= ~BIT3;

if(j_delay > 50000)
{
j_delay=0;

x=0; //enable program2
}

}

Thanks and regards.

over 9 years ago

0 MUKHRAMUDDIN MOHAMMED over 9 years ago

Prodigy 200 points

I mean press and hold the tactile switch for 2-3 seconds.

0 Dennis Eichmann over 9 years ago in reply to MUKHRAMUDDIN MOHAMMED

Guru 74080 points

The interrupt is edge sensitive, not level, so it will only react on the first button press (let's not talk about the contact bouncing here). This means that your delay variable will not increment while the button is pressed.

You can do the following:
Use the button interrupt to start a timer that will test the input after the desired time expired. If the button is still pressed, do whatever you want.

Dennis

0 MUKHRAMUDDIN MOHAMMED over 9 years ago in reply to Dennis Eichmann

Prodigy 200 points

Hi Dennis,

Thanks for the reply.

I understood what you explained.

When i press the button, timer start running for 2- 3 seconds. How i can check whether button is still pressed or not while timer is running.

Thanks.

0 Dennis Eichmann over 9 years ago in reply to MUKHRAMUDDIN MOHAMMED

Guru 74080 points

You only need to test the button at the end of the timer-interval. This can be done by writing

if( !(P1IN & 0x01) ) // Button on P1.0 is pressed (active low)
{
  // Do some action
}

(Button on P1.0 only as example here)

Dennis

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MSP430G2553: Switch interupt