gbulmer
Moderator
I was thinking (dreaming :-) of a 'stripped down' system with threads, time, and something like mailboxes.
I like Erlang (a lot), and it manages very well with asynchronous messaging (but it is designed to have one communication primitive which has to support distributed systems).
I am just starting to appreciate Go lang, and it allows for synchronous (blocking) communications.
There would have to be a way to handle interrupts nicely too ;-)
You can see all aspects of CoOS on site or use goole to search answers.
http://www.google.ru/search?hl=ru&q=coos+task+priority
top links:
http://www.coocox.org/CoOSGuide/CoOS_Semaphores.htm
http://www.coocox.org/CoOSGuide/CoOS_Task_Scheduling.htm
leaflabsandy
Member
<MapleCoOS quick tutorial on The Maple>
Platform: Windows XP/SP3
Device: Maple rev. 3
IDE: 0.0.8 with x893 systick patch.
I applied a "real world" user application using x893's port of CoOs RTOS to the Maple.
I wanted to see how it would work on The Maple.
The following four tasks were created for the MapleCoOS RTOS testing:
-------------------
Task 1:
Description: Reads QVGA touch screen co-ordinates "touch button" and executes a "switch / case"
Priority number: x
Frequency of task: high - as fast a possible to detect touch action
CoTickDelay: None
Resources used: Serial Comport #1 @ 256,000 Baud
Critical Section used: Yes
-------------------
-------------------
Task 2:
Description: Reads QVGA Touch screen and re-awakens uLCD display from power down screen saver mode.
Priority number: x
Frequency of task: Every sec
CoTickDelay: 1000 (1 sec) using 1 ms or 1000 Hz systick interrupt
Resources used: Serial Comport #1 @ 256,000 Baud
Critical Section used: Yes
-------------------
-------------------
Task 3:
Description: Reads Maxim-IC I2C RTC DS3231 for time/date.
Displays time/date on QVGA uLCD screen.
Priority number: x
Frequency of task: Every sec
CoTickDelay: 1000 (1 sec) using 1 ms or 1000 Hz systick interrupt
Resources used: Serial Comport #1 @ 256,000 Baud and Soft-I2C
Critical Section used: Yes
-------------------
-------------------
Task 4:
Description: Checks a 300 sec (5 min) millis() to apply a "screen saver" mode to the QVGA uLCD.
Priority number: x
Frequency of task: Every 10 secs.
CoTickDelay: 10000 (10 sec) using 1 ms or 1000 Hz systick interrupt
Resources used: Serial Comport #1 @ 256,000 Baud
Critical Section used: Yes
-------------------
------
Notes:
------
Note A: Functions CoSchedLock() CoSchedUnlock() are used instead of using a OS_MutexID with
functions CoLeaveMutexSection() CoEnterMutexSection(). Due to multiple resources, the critical
sections of code "resources" were protected by shutting down the scheduler.
Note B: Sytick was setup was changed to 1000 Hz or 1 ms. (default was 10 ms or 100Hz)
CFG_SYSTICK_FREQ (1000) File: <OsConfig.h> in MapleCoOS lib.
Note C: Priority number = The higher the priority number the lower the priority and the max. is 64. See file <OsConfig.h> in MapleCoOS lib.
Note D: Demo task code sample
//Sample task code using critical section:
void task_x(void *pdata)
{
for (;;)
{
CoSchedLock(); // protect critical code resource by locking out task
scheduler.
SerialUSB.write('.'); // protect serialusb resource from other tasks
CoSchedUnlock() // unprotect critical code resource by unlocking task
scheduler.
CoTickDelay(1000); // systick delay? 1ms x 1000 = 1 sec
}
}
---------------------------------------------------------------------------------
Testing a user application using Preemptive Priority: <different task priorities>
---------------------------------------------------------------------------------
Looking at the above tasks, you would think immediately to apply the highest priority to task 1, which obtains the touch co-ordinates from the user and then assign a lower priority to the rest of the tasks. You and I, would be wrong in our logic. By applying the highest priority to the most critical high frequency task, you would be starving the rest of the tasks for microcontroller execution! By applying the highest priority to task 4, then lower priorities to task 3, task 2, and last task 1, you are guaranteeing that all tasks will be serviced and task 1 would be running most of the time as the most critical task in the lowest priority! ("idle task?").
---------------------------------------------------------------------
Testing a user application using round-robin: <same task priorities>
---------------------------------------------------------------------
By applying the same priority to all the tasks then the task scheduler runs the task
according to the "time slice" of each task.
In my application, I could not make this alternative multitasking method to work?
Summary: <--- By using the MapleCoOS careful thought is needed in designing and applying tasks!
-----------------------------------------------------------
Hope this quick tutorial helps. GLTA (Good luck to all) and I hope Gbulmer is asleep
across the pond.
Last two days i read Contiki wiki (http://www.sics.se/contiki/) - look very,very good. I plan make shield with dual interfaces - ENC28J60 (wired) and ZG2100 (wifi). Also i suggest extend headers with a 3.3V near all headers (after AREF (arduino) pin and near extended header) so can make shileds with only one side connection to maple.
leaflabsandy
Member
Gbulmer ... reduced function application code:
/*
Description: uLCD-32PT QVGA Touch --> Maple x-Touch
Author: Hacker
Date: 9/28/10
Time: xxxx
Platform: Win XP SP3
Device: Maple red rev. 3
Maple IDE: 0.0.8 / with x893 systick patch
Additions:
#1. ulcd 5 min screen saver
#2. Added DS3231 RTC
#3. Added time/date to ulcd display
#4. Added 12 touch buttons to ulcd - includes case for code execution
Pending Additions:
When IDE 0.0.7 is released do the following test on com1:
Change speed for display to 256K and change Maple baud to 281K
Works -OK
----------
Status: OK
----------
*/
//---------------------
// Code begin
//---------------------
// Includes / defines
#include <uLCD.h>
#include <colors.h>
#include <Wire.h> // <----- software I2C wire library (alpha) with patch fix
#include <MapleCoOS.h> // <----- CoOS
// General Defines
#define COMM Serial1
#define DIAG Serial2
#define BLUE_LED_PIN 13 // on board blue LED
// MapleCoOS Task Priorities defines
#define Task_2_PRI 10 /* Priority of 'task_2' task. Highest priority Touch Display uLCD Re-Wake 10 */
#define Task_3_PRI 20 /* Priority of 'task_3' task. Higher priority RTC Display 20 */
#define Task_4_PRI 30 /* Priority of 'task_4' task. Lower priority 5 min uLCD Screen Saver 30*/
#define Task_1_PRI 40 /* Priority of 'task_1' task. Lowest priority Touch Screen Processing 40*/
//MapleCoOS Task Size - use default 128
OS_STK Task_1_Stack[TASK_STK_SIZE]; /* Stack of 'task_1' task. */
OS_STK Task_2_Stack[TASK_STK_SIZE]; /* Stack of 'task_2' task. */
OS_STK Task_3_Stack[TASK_STK_SIZE]; /* Stack of 'task_3' task. */
OS_STK Task_4_Stack[TASK_STK_SIZE]; /* Stack of 'task_4' task. */
OS_MutexID mut_uart1; /* Save id of mutex. uLCD */
OS_MutexID mut_uart2; /* Save id of mutex. Diag port */
OS_MutexID mut_soft_I2C; /* Save id of mutex. I2C RTC */
//--------------------------------------------------------------------------------
// MapleCoOS Task Routines
//--------------------------------------------------------------------------------
// Task 1
void task_1(void *pdata) // Get touch co-ordinate and execute switch statement
{
// portait uLCD-32PT(SGC)
ulcd.x_res = 240;
ulcd.y_res = 340;
// ulcd.x_res is the horizontal resolution of the display u are using.
// ulcd.y_res is the vertical resolution of the display u are using.
for (;;)
{
CoSchedLock();
//----------------------------
// Main Button Processing Loop
//----------------------------
toggle ^= 1; // CPU running blue LED
digitalWrite(BLUE_LED_PIN, toggle); // CPU running blue LED
button_Press_Nbr = 0; // reset button number return
get_Touch(); // <--------------<<<< returns button number pressed in global variable "button_Press_Nbr"
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, " ", 1); // opague
switch (button_Press_Nbr){
case 0:
// do nothing - timeout or no touch button pressed
break;
case 1:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 1 Processing", 1); // opague
break;
case 2:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 2 Processing", 1); // opague
break;
case 3:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 3 Processing", 1); // opague
break;
case 4:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 4 Processing", 1); // opague
break;
case 5:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 5 Processing", 1); // opague
break;
case 6:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 6 Processing", 1); // opague
break;
case 7:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 7 Processing", 1); // opague
break;
case 8:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 8 Processing", 1); // opague
break;
case 9:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 9 Processing", 1); // opague
break;
case 10:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 10 Processing", 1); // opague
break;
case 11:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 11 Processing", 1); // opague
break;
case 12:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But 12 Processing", 1); // opague
break;
default:
ulcd.Text(2, 23, LARGE_FONT, 0xFFFF, "But Press Unknown", 1); // opague
// if nothing else matches, do the default
// default is optional
}// end of case
// Display Time Date on ulcd
CoSchedUnlock();
//CoTickDelay(1000); // systick delay? 1ms x 1000 = 1 sec
}
}
// End of Task_1
//--------------------------------------------------------------------------------------
// Task 2
void task_2(void *pdata) // Check touch status to re-awaken from low power mode
{
for (;;)
{
//-------------------------------------------------------------------------
// Touch Scan every second - for LCD display re-awakening from Screen Saver
//-------------------------------------------------------------------------
if ((millis() - startTime_T_Scan) >= interval_T_Scan)
{
CoSchedLock();
get_Touch_Status(); // <--------------<<<<
startTime_T_Scan = millis(); // restart millis timer
CoSchedUnlock();
} // end of millis "if"
CoTickDelay(1000); // systick delay? 1ms x 1000 = 1 sec
}
}
// End of Task_2
//--------------------------------------------------------------------------------------
// Task 3
void task_3(void *pdata) // Get time date from I2C DS3231 and display on uLCD
{
for (;;)
{
// Get Time Date from DS3231 & store in global variables
CoSchedLock();
getDateDS3231(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year); // <----- uses global variables !!!!
// display time date
display_Time_Date();
CoSchedUnlock();
CoTickDelay(1000); // systick delay? 1ms x 1000 = 1 sec
}
}
// End of Task_3
//--------------------------------------------------------------------------------------
// Task 4
void task_4(void *pdata) // Screen Saver 5 min
{
for (;;)
{
//------------------------------
// Blank LCD screen after 5 minutes
//------------------------------
if ((millis() - startTime_Screen_Saver) >= interval_Screen_Saver)
{
CoSchedLock();
ulcd.SetDisplayState (0x00); // display off
ulcd.DisplayControl(0x00, 0x00); // backlight off
CoSchedUnlock();
startTime_Screen_Saver = millis();
ss_Flag = true;
}
CoTickDelay(10000); // systick delay? 1ms x 10000 = 10 sec
}
}
// End of Task_4
//--------------------------------------------------------------------------------------
//----------------------------------------------------------------------
// Setup
//----------------------------------------------------------------------
void setup()
{
DIAG.begin(9600); // Default comport for uLCD display @ 9600
COMM.begin(9600); // Diag comport - for program ack/nak/info
delay(10000); // wait 10 seconds for POR for display and memory card init. Will show splash screen
// move to 3 seconds to skip splash screen
DIAG.println("Check Comm. to 4D Labs Display"); //
ulcd.begin(9600, &COMM); // serial speed 9600
// reset and initialize the display
check_Res(); // check response and print to Diag port
COMM.flush(); // clear serial buffer
delay(100);
DIAG.println("Change or step baud rate up to 256,000 max. baud"); // uLCD does not have autobaud!
ulcd.step_baud_up(); // new baud rate in uLED.cpp (adjustable) set for 256K
delay(100);
check_Res(); // check response
COMM.end(); // end "old" serial comm and restart at the new higher baudrate
COMM.begin(281000); // this value should match the same in uLED.cpp (adjustable) <--- not for 256K !!!!!!! needs 281K
delay(100);
COMM.flush(); // clear serial buffer
//no contrast or brightness control on uLCD <--------------<<<<<<<<<<<<<< ?????????????
//DIAG.println("Set Contrast to 5");
//ulcd.SetContrast(5); // set the contrast of the display to 5 (0 to 15 default (not always) is 8)
//check_Res(); // check response
//delay(500);
DIAG.println("Show Device Display Info");
ulcd.DeviceInfo(); // display some hardware/software info of the screen
COMM.flush(); // clear serial buffer - info also when to the serial port! flush it.
delay(3000); // info will be on screen for 3 seconds
DIAG.println("Clear screen");
ulcd.Cls(); // clears the screen of everything on it. It uses the background color (at this moment it's at default black)
ulcd.Cls(); // keep <---- bug fix - no res without it - needs 2 of them?
check_Res(); // check response
//Set up the LED to blink - for CPU running indicator
pinMode(BLUE_LED_PIN, OUTPUT);
DIAG.println("Redraw display with buttons");
draw_uLCD_Display();
startTime_T_Scan = millis();
delay(10);
startTime_Screen_Saver = millis();
DIAG.println("Turn Touch On");
ulcd.DisplayControl(0x05,0x00); // turn touch on
check_Res(); // check response
DIAG.println("Detect Touch Region"); // The whole screen touch region enabled
ulcd.detect_Touch_Region(0,0,239,319); // whole region <------ modify per application
check_Res(); // check response
DIAG.println("Set Opaque Text");
ulcd.set_Transparent_Opaque_Text(0x01); // Opaque attritube for text mode
check_Res(); // check response
Wire.begin(); // DS3231 I2C pins setup default in cpp >>>-------> I2C- SDA D30 SCL D29
//set_Time_Date(); //<-------------<<<< use once and comment out
delay(1000);
// Initialize / Start RTOS
CoInitOS();
CoCreateTask(task_1, (void *)0, Task_1_PRI, &Task_1_Stack[TASK_STK_SIZE - 1], TASK_STK_SIZE ); //
CoCreateTask(task_2, (void *)0, Task_2_PRI, &Task_2_Stack[TASK_STK_SIZE - 1], TASK_STK_SIZE ); //
CoCreateTask(task_3, (void *)0, Task_3_PRI, &Task_3_Stack[TASK_STK_SIZE - 1], TASK_STK_SIZE ); //
CoCreateTask(task_4, (void *)0, Task_4_PRI, &Task_4_Stack[TASK_STK_SIZE - 1], TASK_STK_SIZE ); //
CoStartOS ();
//------------------------------------------------------------------
} // End of setup
//------------------------------------------------------------------
// the loop() method runs over and over again
void loop()
{
// Do not insert any code here! <-------<<<<<<< !!!!!!
}
leaflabsandy
Member
Quote: "You can insert code in a void loop() - it's execute the same as in standard.
for example blink led or other."
Reply: x893 you just contradicted yourself. See (below) previous statements.
------------------
Questions for x893.
------------------
--------------------------------------------------------------------------------
In your MapleCoOS RTOS you infer that nothing (should/can) run in the main loop()?
All of the sketch tasks are made to run only in their own priority loops in setup()?
// the loop() method runs over and over again
void loop()
{
}
-------------------------------------------------------------------------
In your MapleFreeRTOS RTOS you infer that you can run other sketch code in the main loop
besides the scheduled sketch code in the setup()?
void loop()
{
// Insert background code here
}
------------------------------------------------------------------------------
Your response: <------------<<<<<<<<<<
MapleCoOS and MapleFreeRTOS not use any codes in loop(). <--------<<<<<<<<< ???????????????
SysTick interrupt used for task switching.
You can use loop() for any codes (as early) but it must presents for compile. <-----<<<, ????
setup() procedure called ones and used for task definitions and task scheduler.
I see ChibiOS but it use other task switching method and currently in porting stage.
As for me CoOS and ChibiOS looks better than FreeRTOS (at my opinion).
i wrote that you use loop() the same as before using OS. it's background loop.
i see on code only. this is main procedure:
int main(void)
{
setup();
while (1) {
loop();
}
return 0;
}
you insert CoOS (or other OS) initialization in setup function and after back to main your code still execute
while(1) {
loop();
}
task switch use interrupts but you still can use loop() {...}.
after use pseudo multi tasking you need share resources (in standard loop - only one task and no problem with peripherial resources). for share resources you need use semaphores, mutes, quueses etc.
but loop() { } still work and call time to times. you can't garante priority for loop() so CoOS add own background process with minimal priority but it called.
In a hard loaded application you can't garantee that loop() code executed because it has undeground priority and all RTOS not recommend use it.
P.S. i see to contiki OS - and love it more and more. :)
leaflabsandy
Member
If you put code in the loop() extreme care should be taken. And like you said
Quote: "In a hard loaded application you can't garantee that loop() code executed because it has undeground priority and all RTOS not recommend use it."
By putting code in this "loop()" you cannot use the same resources (SPI,Serial,I2C ...) as in the other task loops or there will be conflicts? Also, there would be no way to know if this code would be "ever" executed in a timely fashion. My advice don't use the loop() if using a RTOS...IMHO
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