The lightweight fiber library has moved to its own project at github, for easier use by Arduino IDE users:
https://github.com/ve3wwg/teensy3_fibers
Git url:
git@github.com:ve3wwg/teensy3_fibers.git
There is an example sketch included in the above repo, but I'll copy it here for your reading convenience:
Code:
// Example Sketch illustrating the use of the fibers library.
#include <fibers.h>
// Allocate up to main + 5 fibers:
Fibers<6> fibers(2000); // main loop() is allocated 2000 bytes of stack
int ledm = 13; // Main LED on teensy 3.x
int led0 = 0; // Digital pin 0
int led1 = 1; // Digital pin 1
int led2 = 2; // Alter to suit
int led3 = 3; // your wiritng preference
uint32_t ffoo = 0; // fibers.create() index for the foo() fiber
uint32_t fbar = 0; // fibers.create() index for bar() etc.
uint32_t fzoo = 0;
void yield() {
fibers.yield(); // Yield cpu to next fiber in round-robin sequence
}
static void
toggle(int led,int& led_state) {
led_state ^= 1; // Alternate state on/off
digitalWrite(led,led_state&1 ? HIGH : LOW); // LED on/off
}
// First fiber (coroutine)
static void foo(void *arg) {
unsigned count = 0;
int led0_state = 0;
while ( count++ < 35 ) {
toggle(led0,led0_state);
delay(230);
}
digitalWrite(led0,LOW);
}
// 2nd fiber (coroutine)
static void bar(void *arg) {
unsigned count = 0;
int led1_state = 0;
while ( count++ < 40 ) {
toggle(led1,led1_state);
delay(250);
}
digitalWrite(led1,LOW);
}
// 3rd fiber (coroutine)
static void zoo(void *arg) {
unsigned count = 0;
int led2_state = 0;
while ( count++ < 47 ) {
toggle(led2,led2_state);
delay(270);
}
digitalWrite(led2,LOW);
}
void setup() {
pinMode(ledm,OUTPUT);
pinMode(led0,OUTPUT);
pinMode(led1,OUTPUT);
pinMode(led2,OUTPUT);
pinMode(led3,OUTPUT);
digitalWrite(ledm,HIGH);
digitalWrite(led0,LOW);
digitalWrite(led1,LOW);
digitalWrite(led2,LOW);
digitalWrite(led3,LOW);
ffoo = fibers.create(foo,0,1000); // Create first coroutine foo(0)
fbar = fibers.create(bar,0,1200); // Create 2nd coroutine bar(0)
fzoo = fibers.create(zoo,0,1100); // Create 3rd coroutine zoo(0)
}
// main thread
void loop() {
unsigned count = 0;
int ledm_state = 0;
digitalWrite(ledm,LOW); // Turn off Teensy LED while main loops
while ( count++ < 20 ) { // Loop only 20 times in main
toggle(led3,ledm_state); // Toggle led3 while main thread runs
delay(350);
}
digitalWrite(ledm,HIGH); // Teensy LED on means it is doing joins
digitalWrite(led3,HIGH);
fibers.join(ffoo); // Stop here until foo() returns
fibers.join(fbar); // Stop here until bar() returns
fibers.join(fzoo); // Stop here until zoo() returns
digitalWrite(led3,LOW); // Indicate pause before restarts
delay(3000);
fibers.restart(0,foo,0); // Restart foo(0) at next yield()
fibers.restart(1,bar,0); // Restart bar(0) at next yield()
fibers.restart(2,zoo,0); // etc..
}
// End arduino_fibers.ino
This sketch requires 4 LEDs to be wired up to see the full effect. LEDs 0, 1, and 2 blink as the fibers (coroutines) foo(), bar() and zoo() blink their respective LEDs at slightly different rates. When the given coroutine "returns", the respective LED will be lit solid. The main loop() blinks the LED3 for the shortest period of time. When it exits its blink loop, it then joins with fibers foo(), bar() and zoo() in that sequence. When the joins have completed, all four LEDs 0 thru 3 will be lit for 3 seconds before the sketch repeats.
The teensy LED (13) is lit as it is doing joins with the other threads. It turns off, while it is performing its own blink action on LED3. I used a bar graph LED (RBG 1000), but you can of course use whatever you have on hand.
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Originally Posted by duff
