servo.detach() for LPM4

[Kris 0]

Hi All,

 

I was wondering if anyone could help? I am trying to drive a servomotor using MSP-EXP430F5529LP. I need to drive the servo to a position, then I disconnect power to the servo using an analog switch. The servo isn't under any great load, so it doesn't move when power is disconnected. Problem is MSP430 is still drawing ~ 525 uA. When I comment out myservo.attach(P2_5), the current consumption drops to the desired 2 uA. I've stripped away most of the code to aid debugging (see below). As far as I can tell, servo.attach() is what's causing the problem. I've read elsewhere that servo.detach() simply stops PWM signals from reaching the previously attached pin (P2_5) and that the timer is still running. Presumably this is why I'm drawing so much current. Can I just set the mode control bit in the TACTL register to stop the timer? Not sure if this would be enough?

 

#include <Servo.h> 
 
Servo myservo; 

void setup() 
{ 
  P1DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT5+BIT6+BIT7;
  P1OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT5)+(~BIT6)+(~BIT7);
  P2DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT6+BIT7;
  P2OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT6)+(~BIT7);
  P3DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT5+BIT6+BIT7;
  P3OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT5)+(~BIT6)+(~BIT7);
  P4DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT5+BIT6+BIT7;
  P4OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT5)+(~BIT6)+(~BIT7);
  P5DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT5+BIT6+BIT7;
  P5OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT5)+(~BIT6)+(~BIT7);
  P6DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT5+BIT6+BIT7;
  P6OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT5)+(~BIT6)+(~BIT7);
  P7DIR |= BIT0+BIT1+BIT2+BIT3+BIT4+BIT5+BIT6+BIT7;
  P7OUT &= (~BIT0)+(~BIT1)+(~BIT2)+(~BIT3)+(~BIT4)+(~BIT5)+(~BIT6)+(~BIT7);
  P8DIR |= BIT0+BIT1+BIT2;
  P8OUT &= (~BIT0)+(~BIT1)+(~BIT2);
  
  myservo.attach(P2_5); 
  delay(100);
  myservo.detach();

  

} 
 
 
void loop() 
{ 

suspend();

}

 

[Kris 0]

Yes, that appears to work. See below.