// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  
// Examples of using interrupts with timer 0
// T0start will begin the program
// This code simply causes an interrupt evey 15 seconds and
// prints a message to the console.
// Use LOOK to see the interupt tables before and after using
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  

// REQUIRES:
// #URL-lib "http://pin1.org/forthlib/flb/General/soft1.flb" sid=99
// #URL-lib "http://pin1.org/forthlib/flb/General/decompile.flb"
// #URL-lib "http://pin1.org/forthlib/flb/Interupts/interrupt.flb"

// To use this type T0start, an interrupt will occur every 10 seconds

// CONSTANTS:
// constants needed for this example
&e0004000 constant T0IR
&e0004004 constant T0TCR
&e0004008 constant T0TC
&e000400c constant T0PR
&e0004014 constant T0MCR
&e0004018 constant T0MR0


// This word will enable fast interrupts for timer0
// in the VIC registers, start timer 0, start it and enable
// the global interrupts which are disabled each time
// an interrupt is called
: setT0
    TIMER0 intSel   // selct
    TIMER0 intEn    // enable
    efiq    // enable irupts, at start up all disabled   
;

// this is the word that gets called when the interrupt is fired
// the word MUST do the following:
// 1. clear the interrupt, in this case it is the timer0 interrupt
// 2. carry out what it needs to do
// 3. re-enable the interrupt if we want to come back here
: T0int
    1 t0IR !    // clear interrupt
    ." Interrupt has occurred" cr
    TIMER0 intEn // re-enable for return
;
// sets timer 1 as a counter, the values
// given makes T0TC increment every 100 us
// or every 0.1ms, in other words 1 second is 
// equal to 1000 counts
// A match has been set up at every 10,000 counts (10 seconds)
// this will generate an interrupt via the T0MCR register
: T0start
    pclk 1000 / T0PR !  // sets regardless of CLK
    2 T0TCR !       // reset
    1 T0TCR !       // enable
    10000 t0MR0 !    // match on 10000
    3 t0MCR !       // interrupt and reset to 0
    setT0           // set interrupts 
    // now place cfa of T0int ti interupt table
    s" T0int" find drop   // get cfa of t0int
    TIMER0    // into timer slot (4)  
    int>>     // do it
; 

: T0stop TIMER0 intDis ;
: look intr. ;