How to use interrupt on Pinguino32

Pinguino32 doesn’t support interrupt routines without writing a code in an assembler file. We decided to open interrupt to everybody. To do this, we used some of the special attribute directive of GCC. Now you can deal with Interrupt without assembler.

This example show how to use the Timer 1 to increment a counter.

// Using interrupt with Pinguino32
// Jean-Pierre MANDON 2011

#include 

unsigned int counter=0;

void ISR_wrapper_vector_4(void) __attribute__ ((section (".vector_4")));
// Put the ISR_wrapper in the good place

void ISR_wrapper_vector_4(void) { Tmr1Interrupt(); }
// ISR_wrapper will call the Tmr1Interrupt()

void Tmr1Interrupt(void) __attribute__ ((interrupt));
// Tmr1Interrupt is declared as an interrupt routine

// define here the code to execute when an interrupt occure
void Tmr1Interrupt(void)
{
if (IFS0bits.T1IF)  // Timer Interrupt flag
{
TMR1=0;   // reset the timer register
IFS0CLR=0x10;  // Clear the timer interrupt flag
counter++;  // increment the counter
}
}

// configure timer 1
void init_timer1(void)
{
IntConfigureSystem(INT_SYSTEM_CONFIG_MULT_VECTOR); // interrupt mode (interrupt.c)
T1CON=0;  // reset timer 1 configuration
TMR1=0;   // reset timer 1 counter register
PR1=0x9999;  // define the preload register
IPC1SET=0x7;  // select interrupt priority and sub-priority
IFS0CLR=0x10;  // clear interrupt flag
IEC0SET=0x10;  // enable timer 1 interrupt
T1CONSET=0x8010; // start timer 1 and set prescaler
}

void setup()
{
init_timer1();
}

void loop()
{
CDC.printf("%d\n\r",counter); // counter is incremented at each timer 1 overflow
delay(1);
}

Be careful, some interruption are already used by Pinguino32. Vector_8 (timer 2) is used by the function millis(). vector_24 (Serial1 interrupt) and vector_32 (Serial2 interrupt) are used by the serial module. vector_35 ( RTCC ) is used by the real time clock module.
All the test have been made with a PIC32-PINGUINO-OTG board and Linux IDE.