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TEN MBED OS Course mutex lab
Diff: main.cpp
- Revision:
- 0:8b346455add1
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Sun Jan 29 20:41:53 2017 +0000 @@ -0,0 +1,98 @@ +/** + * @brief first thread control program with MBED OS + */ +#include "mbed.h" +#include "rtos.h" + +/* declares threads for this demo: */ +const size_t a_stk_size = 1024; +uint8_t a_stk[a_stk_size]; +Thread a_thread(osPriorityNormal, a_stk_size, &a_stk[0]); + +const size_t b_stk_size = 1024; +uint8_t b_stk[b_stk_size]; +Thread b_thread(osPriorityNormal, b_stk_size, &b_stk[0]); + +const size_t printer_stk_size = 2048; +uint8_t printer_stk[printer_stk_size]; +Thread printer_thread(osPriorityHigh, printer_stk_size, &printer_stk[0]); + +/* semaphore to simulate a io driver*/ +Semaphore sema; + +/* Mutex declared to share resource */ +Mutex mtx; + +/* reserve the debbuger uart to shell interface */ +Serial pc_serial(USBTX,USBRX); + +/* ram buffer to be acessed for both a and b threads */ +char ram_console[1024]; + +/** + * @brief thread a function + */ +static void thread_a(void) +{ + const char message[] = {"thread_a writes: Hocus Pocus! Simsalabim!"}; + + for(;;) { + a_thread.wait(10); + /* protect the resource */ + mtx.lock(); + memcpy(&ram_console, &message, sizeof(message)); + sema.release(); + /* release the protected resource */ + mtx.unlock(); + } +} + + +/** + * @brief thread a function + */ +static void thread_b(void) +{ + const char message[] = {"thread_b writes: Abracadabra!"}; + + for(;;) { + b_thread.wait(10); + /* protect the resource */ + mtx.lock(); + memcpy(&ram_console, &message, sizeof(message)); + sema.release(); + /* release the protected resource */ + mtx.unlock(); + } +} + +/** + * @brief thread printer function + */ +static void thread_printer(void) +{ + + for(;;) { + sema.wait(osWaitForever); + /* prints the contents of buffer */ + pc_serial.printf("##[PRINTER_OUT]: %s ## \n\r", ram_console); + + for(int i = 0; i < 0xFFFFFF; i++); + + /* flushes the I/O console */ + memset(&ram_console, 0, sizeof(ram_console)); + } +} + + +/** + * @brief main application loop + */ +int main(void) +{ + pc_serial.baud(115200); + a_thread.start(thread_a); + b_thread.start(thread_b); + printer_thread.start(thread_printer); + return 0; +} \ No newline at end of file