Jaydeep Shah / Mbed OS 10) SEMAPHORE_PART1

SEMAPHORE PART-1 USE OF WAIT_UNTIL() FUNCTION , TIME BASED LOCKING + SEMAPHORE SIGNAL BASED LOCKING IMPLEMENTATION SEMAPHORE BASIC PART 1 USE AND APK JAYDEEP SHAH--radhey04ec@gmail.com

main.cpp@0:a8abf59930e4, 2020-07-12 (annotated)

Committer:
radhey04ec
Date:
Sun Jul 12 07:53:33 2020 +0000
Revision:
0:a8abf59930e4
Child:
1:e0e8a1a599d9
SEMAPHORE WAIT & TIME BASE WAIT ; SEMAPHORE PART 1; BASIC USE OF SEMAPHORE; ; ; JAYDEEP SHAH -radhey04ec@gmail.com

Who changed what in which revision?

UserRevisionLine numberNew contents of line
radhey04ec 0:a8abf59930e4 1 //USE OF PRINTF() STATEMENT IN MBED WITH ISR
radhey04ec 0:a8abf59930e4 2
radhey04ec 0:a8abf59930e4 3 //method : semaphore
radhey04ec 0:a8abf59930e4 4
radhey04ec 0:a8abf59930e4 5 /* NOTE : PRINTF() IS PART OF STDIO.H LIBRARY
radhey04ec 0:a8abf59930e4 6 AND THIS LIBRARY PROTECTED BY MUTEX GUARD, SO YOU CAN NOT CALL PRINTF() FROM
radhey04ec 0:a8abf59930e4 7 ISR FUNCTION.
radhey04ec 0:a8abf59930e4 8 SIMPLE WAY IS USE SOMETYPE OF SIGNAL OR FLAG AND PRINTF() OUTSIDE ISR depends on
radhey04ec 0:a8abf59930e4 9 flag and signal */
radhey04ec 0:a8abf59930e4 10
radhey04ec 0:a8abf59930e4 11 //USE SERIAL TERMINAL WITH 9600 BAUD RATE 8-N-1 FORMAT
radhey04ec 0:a8abf59930e4 12
radhey04ec 0:a8abf59930e4 13 //Created by : JAYDEEP SHAH --radhey04ec@gmail.com
radhey04ec 0:a8abf59930e4 14
radhey04ec 0:a8abf59930e4 15
radhey04ec 0:a8abf59930e4 16 //Library Added :::::
radhey04ec 0:a8abf59930e4 17 #include "mbed.h"
radhey04ec 0:a8abf59930e4 18
radhey04ec 0:a8abf59930e4 19 DigitalOut led(LED1); // ON BOARD LED
radhey04ec 0:a8abf59930e4 20 InterruptIn btn(USER_BUTTON); // ON BOARD BUTTON PORT PC_13
radhey04ec 0:a8abf59930e4 21 //INTERRUPT REGISTERATION
radhey04ec 0:a8abf59930e4 22
radhey04ec 0:a8abf59930e4 23 Semaphore updates(0); //SEMAPHORE OBJECT CREATE = SHARE RESOURCE 0
radhey04ec 0:a8abf59930e4 24 //NO SHARE RESOURCE ONLY ISR
radhey04ec 0:a8abf59930e4 25
radhey04ec 0:a8abf59930e4 26 void do_something() { //ISR FUNCTION
radhey04ec 0:a8abf59930e4 27 // release the semaphore
radhey04ec 0:a8abf59930e4 28 updates.release(); // NOW V=1
radhey04ec 0:a8abf59930e4 29 }
radhey04ec 0:a8abf59930e4 30
radhey04ec 0:a8abf59930e4 31 int main() {
radhey04ec 0:a8abf59930e4 32 btn.fall(&do_something); //FUNCTION CALL WHEN FALL EDGE OF BUTTON - ISR
radhey04ec 0:a8abf59930e4 33
radhey04ec 0:a8abf59930e4 34 while (1) { //LOOP FOREVER
radhey04ec 0:a8abf59930e4 35 // wait for the semaphore to be released from the ISR
radhey04ec 0:a8abf59930e4 36 uint32_t v = updates.wait_until(30000); //RETURN STORE IN V
radhey04ec 0:a8abf59930e4 37
radhey04ec 0:a8abf59930e4 38 // now this runs on the main thread, and is safe
radhey04ec 0:a8abf59930e4 39
radhey04ec 0:a8abf59930e4 40 if(v==1) //THIS ONLY RUN WHEN BUTTON PRESS & SEMAPHORE RELEASE BY 1
radhey04ec 0:a8abf59930e4 41 {
radhey04ec 0:a8abf59930e4 42 led = !led; //LED TOGGLE
radhey04ec 0:a8abf59930e4 43 printf("Toggle LED! V= %d \r\n",v); //SERIAL PRINT V === 0 AGAIN
radhey04ec 0:a8abf59930e4 44 }
radhey04ec 0:a8abf59930e4 45
radhey04ec 0:a8abf59930e4 46 if(v == 0) // This Function run after 30 sec of Power on/RST Continue -- NO matter button press or not
radhey04ec 0:a8abf59930e4 47 {
radhey04ec 0:a8abf59930e4 48 printf("\n TIMER RELEASE SEMAPHORE V = %d \r\n",v);
radhey04ec 0:a8abf59930e4 49 }
radhey04ec 0:a8abf59930e4 50
radhey04ec 0:a8abf59930e4 51 }
radhey04ec 0:a8abf59930e4 52 }