Otherwise wrong value can be read to main code. Volatile long count_2 = 0 //interrupt counter 2Īccess to variables changed in ISR from main code have to be does in atomic style. volatile long count_1 = 0 //interrupt counter 1 ino file at line 29 with: ssd1963 tft (RS, WR, CS, RST) If the class definition is changed so that it inherits from Print like this: class ssd1963 : public Print. This is hint for compiler that variable can change any time and compiler do not use optimization for access to variable. In the display.h file the line at 59 is: class ssd1963 //: public Print. Variables used in interrupts and in main code have to be declared as volatile. It is means values is printing approximately two times per second how many increment is done in 1s? Estimate one loop duration to 10µs, so it is 100000 increments.Type of count_3 is int, so every 2^16(65536) increments overflow to 0 and then is again 1. next time count_3 is incremented only in if statement.count_3 is incremented in if statement and then is incremented in while statement, some data is printed.if sensorVal goes to LOW you must know how long it takes.loop() is called again, again and again in never ending loop.Int sensorVal = digitalRead(4) //read pin 4Ĭount_3++ //increase count so program enters while loop onceĬount_3++ //increase count3 so it never prints again put your main code here, to run repeatedly: Serial.begin(9600) // open the serial port at 9600 bps:ĪttachInterrupt(digitalPinToInterrupt(2), increment_1, RISING) //Enable InterruptĪttachInterrupt(digitalPinToInterrupt(3), increment_2, RISING) //Enable Interrupt put your setup code here, to run once: What is Arduino Serial.availableForWrite(). Return The number of bytes available to write. Get the number of bytes (characters) available for writing in the serial buffer without blocking the write operation. Learn Serial.availableForWrite() example code, reference, definition. Int count_3 = 0 //counter to trigger serial print How to use Serial.availableForWrite() Function with Arduino. So I guess if you switch over to direct serial-send and serial-receive it should work. dont know what the developper of this code thought what he is doing here. How can it enter the while loop when it is larger than 1?! I must be missing something obvious. the function it reads from the serial receivebuffer and just throws away the received bytes. I've printed the values of count_3 inside the while loop to show that it is larger than 1 and it still prints when count_3 is larger than 1. I wrote a while loop to make sure that the values are printed when count_3 =1, but even when count_3 is larger than 1 the values still print. When I pull pin 4 low I want to print the number of counts from pins 2 and 3 once and not multiple times. I wrote code for an Arduino Mega to count the number of times a rising edge occurs on pins 2 and 3 (interrupts).
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