Multi-tasking

As ConVEX is built upon the ChibiOS API, multi-tasking is straightforward and uses it's native multi threading features.

ConVEX creates several default systems tasks.

name	priority	type	description
main	64	static	main program
system	74	static	communicate with the master processor
monitor	72	static	competition control monitor task
ime	73	static	IME background polling
sonar	72	static	ultrasonic sensor polling - if a sonar is enabled
lcd	64	static	LCD display communications
audio	64	heap	audio tone and rttl playback - if audio is enabled
shell	64	static	shell (command line)
operator	65	static	driver control - started from monitor thread
auton	65	static	autonomous - started from monitor thread

To create a static task using the ChibiOS API, code in the following form is used. If the task needs to be stopped by competition control then vexTaskRegister should be called near the beginning of the task and vexSleep called to yeild processing rather than the ChibiOS function chThdSleepMilliseconds.

// memory for task - use the WORKING_AREA macro
static WORKING_AREA(waVexTestThread, 512);
static msg_t
vexTestThread( void *arg )
{
  (void)arg;
  // register the task so competition control can kill it
  vexTaskRegister(("test");
  
  // thread processing
  while (TRUE)
      {
    // use vexSleep rather than chThdSleepMilliseconds
      vexSleep(25);
      }

  return (msg_t)0;
}

void
MyFunc()
{
    // Creates the test thread.
    chThdCreateStatic(waVexTestThread, sizeof(waVexTestThread), NORMALPRIO-1, vexTestThread, NULL);
}

See vexcortex.c for more information on vexTaskRegister and other thread related functions.

An alternative way of creating tasks uses a ROBOTC style API.

#include "robotc_glue.h"

task
vexTestThread( void *arg )
{
  (void)arg;

  vexTaskRegister("test");

  while (TRUE)
      {
      wait1Msec(25);
      }

  return (msg_t)0;
}

void
MyFunc()
{
    // Creates the test thread.
    StartTask( vexTestThread );
}

This creates the thread using dynamic memory allocation and allocates a fixed 512 bytes for it. The task should still be registered using vexTaskRegister so competition control can stop it if necessary.

See robotc_glue.c and robotc_glue.h for more details on ROBOTC style tasks.