This demo uses the mbed RTOS to run eight threads (including main). The threads are using different I/O devices on the application board. Several of the threads output to the LCD and an OS mutex lock is used to control access to the LCD and make the LCD thread safe.
Dependencies: C12832_lcd LCD_fonts mbed-rtos mbed
Fork of lab1 by
main.cpp
- Committer:
- dreschpe
- Date:
- 2012-12-05
- Revision:
- 3:3ec443c0842a
- Parent:
- 2:a69c8c5f5b03
- Child:
- 4:79863d2ea5a0
File content as of revision 3:3ec443c0842a:
// example to test the mbed Lab Board lcd lib with the mbed rtos // Pot1 change the contrast // Pot2 change the speed of the sin wave #include "mbed.h" #include "rtos.h" #include "Small_6.h" #include "Small_7.h" #include "Arial_9.h" #include "stdio.h" #include "C12832_lcd.h" // LCD object C12832_LCD LCD; AnalogIn Pot1(p19); AnalogIn Pot2(p20); // mutex to make the lcd lib thread save Mutex lcd_mutex; // Thread 1 // print counter into first line and wait for 1 s void thread1(void const *args) { int i; while(true) { // thread loop lcd_mutex.lock(); LCD.locate(0,0); LCD.set_font((unsigned char*) Small_6); LCD.printf("Thread1 count: %d",i); lcd_mutex.unlock(); i++; Thread::wait(1000); } } // Thread 2 // print counter into third line and wait for 0,5s void thread2(void const *args) { int k; while(true) { // thread loop lcd_mutex.lock(); LCD.locate(0,20); LCD.set_font((unsigned char*) Arial_9); LCD.printf("Thread 2 count : %d",k); lcd_mutex.unlock(); k++; Thread::wait(500); // wait 0.5s } } // Thread 3 // print a sin function in a small window // the value of pot 1 change the speed of the sinwave void thread3(void const *args) { int i,k,v; double s,a; k = 1; lcd_mutex.lock(); LCD.rect(89,0,127,17,1); lcd_mutex.unlock(); while(true) { // thread loop v = Pot1.read_u16(); // get value of pot 1 lcd_mutex.lock(); for (i=90; i<127; i++) { s = 8 * sin((long double)(i+k) /5); // pixel to print a = 8 * sin((long double)(i+k-1) /5); // old pixel to erase LCD.pixel(i,9 + (int)a ,0); // erase pixel LCD.pixel(i,9 + (int)s ,1); // print pixel } LCD.copy_to_lcd(); // LCD.pixel do not update the lcd lcd_mutex.unlock(); k++; Thread::wait(v/100); // value of pot1 / 100 } } // Thread 4 // input pot 2 and change the contrast of lcd void thread4(void const *args) { int k; while(true) { // thread loop k = Pot2.read_u16(); // get the value of poti 2 k = k >> 10; // we need only 6 bit for contrast lcd_mutex.lock(); LCD.set_contrast(k); lcd_mutex.unlock(); Thread::wait(500); // wait 0.5s } } // print the actual contrast int main() { int j; LCD.cls(); Thread t1(thread1); //start thread1 Thread t2(thread2); //start thread2 Thread t3(thread3); //start thread3 Thread t4(thread4); //start thread4 while(true) { // main is the next thread lcd_mutex.lock(); LCD.locate(0,9); LCD.set_font((unsigned char*) Small_7); j = LCD.get_contrast(); // read the actual contrast LCD.printf("contrast : %d",j); lcd_mutex.unlock(); Thread::wait(500); // wait 0.5s } }