mail box

mail box


    Designers Guide to the Cortex-M Family
    CMSIS mailbox Example
#include "STM32F10x.h"
#include "cmsis_os.h"
#include "Board_LED.h"

typedef struct                                  //define the mail slot format
    uint8_t LED0; 
    uint8_t LED1; 
    uint8_t LED2; 
    uint8_t LED3;
} mail_format;

osMailQDef(mail_box, 16, mail_format);                  //define the mailbox 
osMailQId  mail_box;                                                        //define the mailbox id

void LED_Producer (void const *argument) 
    uint8_t led0[12] = {1,0,0,0,1,1,1,1,0,0,0,0};                                   //create the patterns to send to the mailbox
    uint8_t led1[12] = {0,2,0,0,0,2,2,2,2,0,0,0};
    uint8_t led2[12] = {0,0,4,0,0,0,4,4,4,4,0,0};
    uint8_t led3[12] = {0,0,0,8,0,0,0,8,8,8,8,0};
    uint8_t index;
    mail_format *LEDtx;                                                             //define a pointer in the mailslot format

    while (1) 
            LEDtx = (mail_format*)osMailAlloc(mail_box, osWaitForever);         //allocate a mailslot
            LEDtx->LED0 = led0[index];                                          //Populate it with data
            LEDtx->LED1 = led1[index];
            LEDtx->LED2 = led2[index];
            LEDtx->LED3 = led3[index];
            osMailPut(mail_box, LEDtx);                                         //Post the mail to the mailbox

void LED_Consumer (void const *argument) 
    osEvent evt;                                                                    //declare an osEvent variable
    mail_format *LEDrx;                                                             //define a pointer in the mailslot format

    while (1) 
        evt = osMailGet(mail_box, osWaitForever);                               //wait until a message arrives
        if(evt.status == osEventMail)                                           //Check for a valid message
            LEDrx = (mail_format*)evt.value.p;                                  //Set the receive pointer to the mailslot
            LED_SetOut(LEDrx->LED0|LEDrx->LED1|LEDrx->LED2|LEDrx->LED3);        //Use the data
            osMailFree(mail_box, LEDrx);                                        //Free the mailslot

osThreadDef(LED_Producer, osPriorityNormal, 1,0);
osThreadDef(LED_Consumer, osPriorityNormal, 1,0);

int main (void) 
    osKernelInitialize ();                    // initialize CMSIS-RTOS

    LED_Initialize ();
    mail_box = osMailCreate(osMailQ(mail_box), NULL);                           // Create the mailbox
    osThreadCreate(osThread(LED_Producer), NULL);
    osThreadCreate(osThread(LED_Consumer), NULL);

    osKernelStart ();                         // start thread execution