====== OSA : example for PIC10 ======








===== Project =====

This example demonstrates using RTOS OSA under 12-bit microcontroller. Unrar file {{osa:3leds.rar|3leds.rar}} into folder "C:\TEST\3LEDS". This programm written under **PIC10F222** (you can rebuild it under **F202** or **206**).

This program forms PWM signals to drive 7-color LED. It slowly changes width of pulses for every LED. There are four speeds of color changing.





===== Scheme =====

Here is scheme of device. Controller drives three n-p-n transistors. Every transistor controls LED. Notice that buttons and transistors are connected to same pins.

{{osa:ref:appendix:3leds_pic10f.jpg}}

Button ##S1## makes red LED active.\\
Button ##S2## makes green LED active.\\
Button ##S3## makes blue LED active.\\
Button ##S4## canges work speed.\\


**Note.** Values of resistors **R11**, **R12** and **R13** are selected according to used LEDs.

===== Work description =====
Program contains three tasks:
  * ##Task_Leds## - forming pulses to drive LEDs.
  * ##Task_Work## - forming values of length for each LED.
  * ##Task_Buttons## - sans buttons.

----


==== Task_Leds ====

This task waits for TMR0 overflow. When overflow occures, all active LEDs are switchs on. Then task waits for TMR0 becames greater than intensity value of each LED and switch corresponding LED off. Program has three variables holding intensity values for each LED. When all LEDs becames switched off, other tasks can get control.

Two other tasks (##Task_Work## and ##Task_Button##) waits for setting bits **//bRunTaskWork//** and **//bRunTaskButtons//** respectively. This bits are set by ##Task_Leds## after all LEDs switchs off.


==== Task_Work ====

When task gets control, it checks is it time to change intenesity variables. There is a variable **//Speed//**. It's value changes every time when task get control. Speed of increasing (speed of intensity changing) are set by two MSB bits of variable **//Speed//** (Speed.cSpeed). When 5 lowes bits of variable **//Speed//** (Speed.cPrs) overflows, bit Speed.bTimeout becames set and function ##ChangeIntensity()## called. This functions changes intensity values of all LEDs (variables **//Red//**, **//Green//** and //**Blue**//).

<note>
Function ##ChangeIntensity()## is not a part of RTOS, thus you can to modify it as you wish to make your own intensity changing style.
</note>



==== Task_Button ====

This task gets control one time in every 16 milliseconds, when bit **//bRunTaskButtons//** becames set. First all pins set as inputs. Then program checks state of pins: if any pin eq. to "0", then corresponding button is pressed. Buttons ##SW1##, ##SW2## and ##SW3## set intensity of red, green or blue at maximum, respectively (two other LEDs will be switched off). Button ##SW4## increases value of Speed.cSpeed by 1. After all buttons checked, task waits for button release. Before exit from task, all pins set as output.


===== Photos =====


{{osa:ref:appendix:color2.jpg}}{{osa:ref:appendix:color5.jpg}}{{osa:ref:appendix:color7.jpg}}{{osa:ref:appendix:color8.jpg}}

{{osa:ref:appendix:color9.jpg}}{{osa:ref:appendix:color10.jpg}}{{osa:ref:appendix:color11.jpg}}{{osa:ref:appendix:color12.jpg}}