Felipe Neves
/
TEN_mbedos_sema
TEN MBED OS Course semaphore lab
main.cpp@0:a59680ccdb41, 2017-01-29 (annotated)
- Committer:
- uLipe
- Date:
- Sun Jan 29 20:42:21 2017 +0000
- Revision:
- 0:a59680ccdb41
first;
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
uLipe | 0:a59680ccdb41 | 1 | /** |
uLipe | 0:a59680ccdb41 | 2 | * @brief first thread control program with MBED OS |
uLipe | 0:a59680ccdb41 | 3 | */ |
uLipe | 0:a59680ccdb41 | 4 | #include "mbed.h" |
uLipe | 0:a59680ccdb41 | 5 | #include "rtos.h" |
uLipe | 0:a59680ccdb41 | 6 | |
uLipe | 0:a59680ccdb41 | 7 | /* declares threads for this demo: */ |
uLipe | 0:a59680ccdb41 | 8 | const size_t a_stk_size = 1024; |
uLipe | 0:a59680ccdb41 | 9 | uint8_t a_stk[a_stk_size]; |
uLipe | 0:a59680ccdb41 | 10 | Thread a_thread(osPriorityHigh, a_stk_size, &a_stk[0]); |
uLipe | 0:a59680ccdb41 | 11 | |
uLipe | 0:a59680ccdb41 | 12 | const size_t b_stk_size = 1024; |
uLipe | 0:a59680ccdb41 | 13 | uint8_t b_stk[b_stk_size]; |
uLipe | 0:a59680ccdb41 | 14 | Thread b_thread(osPriorityNormal, b_stk_size, &b_stk[0]); |
uLipe | 0:a59680ccdb41 | 15 | |
uLipe | 0:a59680ccdb41 | 16 | /* Demo how to declare a semaphore */ |
uLipe | 0:a59680ccdb41 | 17 | Semaphore sema; |
uLipe | 0:a59680ccdb41 | 18 | |
uLipe | 0:a59680ccdb41 | 19 | |
uLipe | 0:a59680ccdb41 | 20 | /* reserve the debbuger uart to shell interface */ |
uLipe | 0:a59680ccdb41 | 21 | Serial pc_serial(USBTX,USBRX); |
uLipe | 0:a59680ccdb41 | 22 | |
uLipe | 0:a59680ccdb41 | 23 | |
uLipe | 0:a59680ccdb41 | 24 | /** |
uLipe | 0:a59680ccdb41 | 25 | * @brief thread a function |
uLipe | 0:a59680ccdb41 | 26 | */ |
uLipe | 0:a59680ccdb41 | 27 | static void thread_a(void) |
uLipe | 0:a59680ccdb41 | 28 | { |
uLipe | 0:a59680ccdb41 | 29 | pc_serial.printf("## started thread_a execution! ##\n\r"); |
uLipe | 0:a59680ccdb41 | 30 | |
uLipe | 0:a59680ccdb41 | 31 | for(;;) { |
uLipe | 0:a59680ccdb41 | 32 | |
uLipe | 0:a59680ccdb41 | 33 | /* adds dummy processing */ |
uLipe | 0:a59680ccdb41 | 34 | for(int i = 0 ; i < 0xFFFFFF; i++); |
uLipe | 0:a59680ccdb41 | 35 | |
uLipe | 0:a59680ccdb41 | 36 | pc_serial.printf("## thread_a will take the semaphore! ##\n\r"); |
uLipe | 0:a59680ccdb41 | 37 | //a_thread.yield(); |
uLipe | 0:a59680ccdb41 | 38 | |
uLipe | 0:a59680ccdb41 | 39 | /* once executed, gives thread_a to do so, and sync the two tasks */ |
uLipe | 0:a59680ccdb41 | 40 | sema.wait(osWaitForever); |
uLipe | 0:a59680ccdb41 | 41 | pc_serial.printf("## thread_a took the semaphore! ##\n\r"); |
uLipe | 0:a59680ccdb41 | 42 | |
uLipe | 0:a59680ccdb41 | 43 | } |
uLipe | 0:a59680ccdb41 | 44 | } |
uLipe | 0:a59680ccdb41 | 45 | |
uLipe | 0:a59680ccdb41 | 46 | |
uLipe | 0:a59680ccdb41 | 47 | /** |
uLipe | 0:a59680ccdb41 | 48 | * @brief thread a function |
uLipe | 0:a59680ccdb41 | 49 | */ |
uLipe | 0:a59680ccdb41 | 50 | static void thread_b(void) |
uLipe | 0:a59680ccdb41 | 51 | { |
uLipe | 0:a59680ccdb41 | 52 | pc_serial.printf("## started thread_b execution! ##\n\r"); |
uLipe | 0:a59680ccdb41 | 53 | |
uLipe | 0:a59680ccdb41 | 54 | for(;;) { |
uLipe | 0:a59680ccdb41 | 55 | |
uLipe | 0:a59680ccdb41 | 56 | /* adds dummy processing */ |
uLipe | 0:a59680ccdb41 | 57 | for(int i = 0 ; i < 0xFFFFFF; i++); |
uLipe | 0:a59680ccdb41 | 58 | |
uLipe | 0:a59680ccdb41 | 59 | pc_serial.printf("## thread_b will signal the semaphore! ##\n\r"); |
uLipe | 0:a59680ccdb41 | 60 | |
uLipe | 0:a59680ccdb41 | 61 | //b_thread.yield(); |
uLipe | 0:a59680ccdb41 | 62 | |
uLipe | 0:a59680ccdb41 | 63 | /* release the semaphore and allow the high priority task to run */ |
uLipe | 0:a59680ccdb41 | 64 | sema.release(); |
uLipe | 0:a59680ccdb41 | 65 | pc_serial.printf("## thread_b signaled the semaphore, but thread_a consumed it! ##\n\r"); |
uLipe | 0:a59680ccdb41 | 66 | } |
uLipe | 0:a59680ccdb41 | 67 | } |
uLipe | 0:a59680ccdb41 | 68 | |
uLipe | 0:a59680ccdb41 | 69 | |
uLipe | 0:a59680ccdb41 | 70 | |
uLipe | 0:a59680ccdb41 | 71 | /** |
uLipe | 0:a59680ccdb41 | 72 | * @brief main application loop |
uLipe | 0:a59680ccdb41 | 73 | */ |
uLipe | 0:a59680ccdb41 | 74 | int main(void) |
uLipe | 0:a59680ccdb41 | 75 | { |
uLipe | 0:a59680ccdb41 | 76 | pc_serial.baud(115200); |
uLipe | 0:a59680ccdb41 | 77 | a_thread.start(thread_a); |
uLipe | 0:a59680ccdb41 | 78 | b_thread.start(thread_b); |
uLipe | 0:a59680ccdb41 | 79 | return 0; |
uLipe | 0:a59680ccdb41 | 80 | } |