Microchip Technology SW006023-3N Data Sheet

®

DS51686E-page 138

 2012 Microchip Technology Inc.

/*  Blink an LED on the PIC32MX Ethernet Starter Kit using the

 *  PIC32MX795F512L target device.

 */

#include <xc.h>

#include <plib.h>

#include <sys/attribs.h>

// Configuration Bit settings using the config pragma

// SYSCLK = 80 MHz (8MHz Crystal/ FPLLIDIV * FPLLMUL / FPLLODIV)

// PBCLK = 10 MHz

// Primary Osc w/PLL (XT+,HS+,EC+PLL)

// WDT OFF

// Other options are “do not care”

//

#pragma config FPLLMUL=MUL_20, FPLLIDIV=DIV_2, FPLLODIV=DIV_1, FWDTEN=OFF

#pragma config POSCMOD=HS, FNOSC=PRIPLL, FPBDIV=DIV_8

// Calculate the PR1 (period) at compile time

#define SYS_FREQ                (80000000L)

#define PB_DIV                  8

#define PRESCALE                256

#define TOGGLES_PER_SEC         1

#define T1_TICK                 (SYS_FREQ/PB_DIV/PRESCALE/TOGGLES_PER_SEC)

int main(void)

{

  // STEP 1

  // Configure the device for maximum performance but do not change the PBDIV

  // Given the options, this function will change the flash wait states, RAM

  // wait state and enable prefetch cache but will not change the PBDIV.

  // The PBDIV value is already set via the config pragma FPBDIV option above.

  SYSTEMConfig(SYS_FREQ, SYS_CFG_WAIT_STATES | SYS_CFG_PCACHE);

  //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  // STEP 2. configure Timer 1 using internal clock, 1:256 prescale

  OpenTimer1(T1_ON | T1_SOURCE_INT | T1_PS_1_256, T1_TICK);

  // set up the timer interrupt with a priority of 7

  ConfigIntTimer1(T1_INT_ON | T1_INT_PRIOR_7);

  

  // enable multi-vector interrupts

  INTEnableSystemMultiVectoredInt();

  // configure PORTDbits.RD0 = output

  mPORTDSetPinsDigitalOut(BIT_0);

  while(1);

}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

// STEP 3. configure the Timer 1 interrupt handler

// Determine shadow-register or software-stack context saving at

// runtime by using the IPL7AUTO priority specifier.

// Note that the n value in IPLnAUTO _must_ match the priority

// of the timer1 interrupt source configured above.

#ifdef __cplusplus

  // For C linkage when compiling for C++

  extern "C" {

#endif /* __cplusplus */