// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  
// flash an led on p0.31
// This is the simplest example of Forth code and in this
// file you can see how the required library is automatically
// downloaded form the pin1.org site
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  

// REQUIRES:
// #URL-lib "http://pin1.org/forthlib/flb/General/pinsel.flb" sid=55

// #currentSID sid=10

// CONSTANTS:
// There are no constants but the following variable is defined
// in order to reflect the current state of the port.
variable tog

// set p31 to an output, -ve numbers are used for port 1 and
// +ve for port 0
: p0.31-setup
    31 io-out   // set p0.31 to o/p
    0 tog !     // set variable to 0
;

// turns on or off using p!
// 1 = on, 0 = off
// ( 0|1 ---)
: p0.31    
  0= 31 p!
;    

// toggles p0.31, if its on, claaing this will switch it off
// and vice-versa
: p0.31-toggle
    tog @ 0= dup tog !
    p0.31
;

: <0>go
    p0.31-setup
    begin
        100 ms
        p0.31-toggle
        key?
    until
;

// #currentSID sid=0