Project Logs

Collapse

• Port Initialization

  Adi Vivek • 12/11/2018 at 19:57 • 0 comments

  Now lets look at how to use the pins for output.

  There are many ports on the MSP430 (varies on version) , for example PORT-1  ( P1.0 to p1.7 ) & 

  PORT-2 ( P2.0 to P2.7 ).

  #include <msp430.h> 
  
  
  /**
   * main.c
   */
  void main(void)
  {
  	WDTCTL = WDTPW | WDTHOLD;	// stop watchdog timer
  
  	 P3DIR=0xFF;                    // P3DIR=0x00;
           P6DIR=0xFF;
  
           P4DIR |=0x00;
           P4REN |=0xFF;
           P4OUT |=0xFF;
  
  }
  

   P3DIR |=0x00 tells us that the whole of PORT-3 is initialized to take inputs.

  P3DIR |=0xFF tells us that the whole of PORT-3 is initialized to give outputs.
  

  P3DIR |=0x01 only the pin P3.0 is initialized to output in PORT-3.

  This follows a Hexadecimal Port mapping.

  The Major advantage with the higher versions of MSP430 are , they have inbuilt Pull -Up or Down resistors, so no need to connect externally.
  

  P4REN |=0xFF , this indicates that the pins of PORT-4 have their pull up/down resistors enabled.

  TO select them between Pull UP or Pull DOWN, the instruction P$OUT |=0xFF is used.

  If 0xFF is used they configure as Pull UP resistors and if 0x00 they configure as Pull DOWN. 

• INSIGHTS

  Adi Vivek • 12/11/2018 at 19:39 • 0 comments

  Let's Begin!

  Initialize the watchdog timer to OFF state using the required password for the watchdog timer

  (It helps to keep check of infinite loops , keeping the processor safe).

  #include <msp430f5529.h>         // or #include <msp430.h>
  
  
  /**
   * main.c
   */
  int main(void)
  {
  	WDTCTL = WDTPW | WDTHOLD;	// The HOLD bit is 1
  	
  	return 0;
  }

  WDTCTL is the watch dog timer control register. 

  One of the Bit is WDTHOLD , this can be accessed through a specific password value WDTPW.

  From WDTHOLD one can control ON and OFF of a Watchdog timer.

View all 2 project logs