![](/media/cache/group/mcu.png.50x50_q85.jpg)
Simple example to use a Mempool object together with a Queue object in order to send more complex messages from thread1 to thread2.
Diff: main.cpp
- Revision:
- 0:2a0e4f8a7b76
diff -r 000000000000 -r 2a0e4f8a7b76 main.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Tue Feb 23 13:32:14 2016 +0000 @@ -0,0 +1,88 @@ +/** 10_rtos_mempool + * + * Simple example to use a Mempool object together with a Queue + * object in order to send more complex messages from thread1 to thread2. + * Thread1 generates transition between random RGB colors and sends + * messages to Thread2. Thread2 displays the requested color on the + * built in RGB LED. + * + * Data items for messages are stored in a MemoryPool object. + * Thread1 allocates MemoryPool slots, Thread2 should free up + * these slots after using up data stored in the slot. + */ + +#include "mbed.h" +#include "rtos.h" +PwmOut rled(LED_RED); +PwmOut gled(LED_GREEN); +PwmOut bled(LED_BLUE); + +typedef struct { + float red; + float green; + float blue; +} message_t; + +MemoryPool<message_t, 4> mpool; //Memory pool for data storage +Queue<message_t, 4> queue; //Message queue for 4 items + +void led_thread(void const *argument) +{ + rled.period_ms(20); //Set period to 20 ms + rled.write(1.0f); //Initialize to 0% duty cycle + gled.period_ms(20); //Set period to 20 ms + gled.write(1.0f); //Initialize to 0% duty cycle + bled.period_ms(20); //Set period to 20 ms + bled.write(1.0f); //Initialize to 0% duty cycle + while (true) { + osEvent evt = queue.get(); //Wait for a message + if(evt.status == osEventMessage) { + message_t *mymessage = (message_t*)evt.value.p; + rled = 1.0f - mymessage->red; + gled = 1.0f - mymessage->green; + bled = 1.0f - mymessage->blue; + mpool.free(mymessage); //Free up memory + } + } +} + +float frand(void) +{ + float rv = (float)(rand()&0xFFFF); + return (rv/65536.0f); +} + +int main (void) +{ + float RGB1[3]; + float RGB2[3]; + float INC[3]; + Thread thread2(led_thread); +//--- Create a random color --------------------- + for (int x=0; x<3; x++) { + RGB1[x] = frand(); + } + + while (true) { +//--- Create a new random color ----------------- + for (int x=0; x<3; x++) { + RGB2[x] = frand(); + } +//--- Determine increments to go from color 1 to color 2 in 25 steps + for (int x=0; x<3; x++) { + INC[x] = (RGB1[x] - RGB2[x]) / 25; + } +//--- Send color codes to thread2 --------------- + for (int s=0; s<25; s++) { + message_t *message = mpool.alloc(); //Allocate memory + message->red = RGB1[0]; + message->green = RGB1[1]; + message->blue = RGB1[2]; + queue.put(message); //Send data as message + Thread::wait(100); + for (int x=0; x<3; x++) { + RGB1[x] -= INC[x]; //Approach to second colour + } + } + } +}