g. If delay is larger than 10 milliseconds and not in ISR, it is the same as wait_ms. Basically, I found out that delayMicroseconds(x) delays (on Arduino UNO, 16MHz) 7 Clock cycles for (x = 0, 1) 14 Clock cycles Short for (x >= 2) I noticed a too quick delay on 'x = 2' case. e esp_timer_get_time() return a int64_t value and is parsed as uint32_t in delayMicroseconds(). (There are 1000 milliseconds in a second. If we would change from HIGH to LOW and back to HIGH as fast as we can, then. On the boards from the Arduino Portenta family this function has a resolution of one microsecond on all cores. I found the minimum value for the delay between steps to be around 300 microseconds. 1 cm = 0,393701 in. us: the number of microseconds to pause (unsigned int) Returns. uint64_t microseconds = esp_timer_get_time (); // Starting the count, it exits. h Arduino library allows the use of up to 8 servos moving asynchronously (because it uses interrupts). //microseconds of on-time long OffTime = 2; //microseconds of off-time unsigned long previousMillis = 0; //will store last time viewTime was updated int. Currently, the largest value that will produce an accurate delay is 16383. // This code is for testing analogRead delay // Compiled using Arduino IDE // ESP32-WROOM-DA Module // Board is ESP WROOM 32 made by // Does nothing more than fire a periodic timer // interrupt every 200 microseconds and an analogRead // inside the ISR: PinTEST is high before read, // then is low. Note that some manufactures do not follow this standard very. hw_timer_t * timerBegin(uint32_t frequency); frequency select timer frequency in Hz. Certain things do go on while the delay () function is controlling the Atmega chip however, because the delay function does not disable interrupts. This number will overflow (go back to zero), after approximately 70 minutes. I've tried to use 'delay(Sampling_Period_in_Milliseconds)' at the end of each iteration, but so far it hasn't worked very well. pulseIn(echoPin, HIGH) will actually wait for the ECHO pin go HIGH, then start measuring the pulse length until it goes LOW again. At this stage, you should see new examples appear under the file menu, and the following code should compile. Nick Gammon's Interrupts Tutorial:. For delays longer than a few thousand microseconds, you should use the delay() function instead. [imported] #576. Holds Now() for the next same period. Unsigned longs on the arduino can reach from 0 to 4,294,967,295. Currently, the largest value that will produce an accurate delay is 16383. Pauses the program for the amount of time (in microseconds) specified by the parameter. 25 and 0. void setup () { Serial. ザ・ delayMicroseconds () 関数は単一の整数（または数値）引数を受け入れます。. Example code HC-SR04 with I2C LCD and Arduino. All without using the delay() function. ino」と間違えていたので、「platformio. There are a thousand microseconds in a millisecond, and a million microseconds in a second. This number will overflow (go back to zero), after approximately 70 minutes. Down at the very bottom you'll see two core task. Description. Open Arduino IDE, select the right board and port. The same technique can be used with micros(). Pauses the program for the amount of time (in microseconds) specified as parameter. Unfortunately, the appropriate headers aren't included in the standard include path, and just dropping them in there doesn't work, either. This could change in future Arduino releases. 008 seconds of overhead)system July 15, 2008, 10:24pm 3. So, cycles is NOT less than RESOLUTION - 1, therefore it was more than maximum. I have changed that to say 1500 Micros. Rinse and repeat as needed. More knowledgeable programmers usually avoid the use of delay () for timing of events longer than 10’s of milliseconds unless the Arduino sketch is very simple. Check the blink Arduino program for an example. delay(60000); // 1 minute = 60x1000 = 60,000 milliseconds. According to Arduino Advance I/O Reference, the function pulseIn () reads a pulse either HIGH or LOW on a pin. delayMicroseconds(us) Parameters. micros() seems to run at the correct rate. Now let us compare delay for 1, 10, 100 and 1000 milliseconds using the vTaskDelay() function. Then, Lets assume the servo potentiometer is approximately set to. void delayMicroseconds (unsigned int us) { // calling avrlib's delay_us() function with low values (e. I need a micro second accuracy to properly control a stepper motor, and I came across inconsistent delays as the delay increases. Returns the length of the pulse in microseconds or gives up and returns 0 if no complete pulse was received within the timeout. The period is actually 5. Syntax – delay (ms) delay function takes only one argument, Which will be the amount of time we have to pause the code. This number is quite large but is well within the scope of an unsigned long: 32 bits = (2^32. Currently, the largest value that will produce an accurate delay is 16383. IN,. By vilaskafre - Thu Jul 16, 2020 6:00 am - Thu Jul 16, 2020 6:00 am #217174. For example delayMicroseconds(2) takes 330. With delay(), you can wait up to 429497295 ms, or about 49. There are a thousand microseconds in a millisecond, and a million microseconds in a second. timera – considering that we want to blink the LED every second, we insert the frequency 1Hz. La aproximación es debida a la ejecución de las otras instrucciones en el código. system March 16, 2012, 4:40pm 1. (Hint: rename the class to microDelay and replace. Program: void f_Delay_Micro_Sec( unsigned int Delay) { unsigned long useconds, useconds_Dif; char. Arrch July 31, 2012, 9:44pm 2. The code returns the number of microseconds since the Arduino board began. Done as Nick suggested. ), delay() uses the micros() function which itself requires timer interrupts to increment a counter. This the code. e. To do that, you need to make an output pin go Hi & Lo. Limitations If you are using. The Reason I am posting on here is to share this test. This number overflows i. Currently, the largest value that will produce an accurate delay is 16383. Bagi kalian yang belum mengenal apa itu ARDUINO IDE, Arduino dan Microcontroller, silahkan baca terlebih dahulu artikel. g. The Arduino delay is ok - as long as you don't send command message too often… On the computer side there is no "while loop in ms" - it iterates AS FAST AS POSSIBLE! Best regards, GerdW using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019Arduino cuenta con un conjunto básico de funciones para el manejo de tiempo, y estas son: millis, micros, delay y delayMicroseconds. 6. 08. The sensor’s pins are connected to the microcontroller as described in Figure 7. Pauses the program for the amount of time (in microseconds) specified as parameter. Using "delayMicroseconds ()", that delay can be specified with microsecond resolution. The code below prints the word. It only takes a minute to sign up. unsigned long time; void setup() { Serial. Erfahrene Programmierer vermeiden normalerweise die Verwendung von delay () für das Timing von Ereignissen, die länger als 10 Millisekunden sind, es sei denn, der Arduino-Sketch ist sehr einfach. The station reflects the incoming time as it is. Hi, I have several tasks in freeRTOS on my ESP32 delaying with the vTaskDelay-function. It takes around 2 microseconds for digitalWrite to change the state of a pin. I need a prefect sampling rate so these 3 microseconds are going to add up quickly. This. get microseconds, up to a couple of hours, I think. There are a thousand microseconds in a millisecond and a million microseconds in a second. e. When the IDE opens, notice that it automatically opens the "Timer2_Counter. println (println = print line) function to print the value of millis. All without using the delay() function. The delayMicroseconds function which is like the delay function except you specify the time in microseconds. Delay time is somewhere in the range of a few hundred microseconds to a couple milliseconds. a more important difference between the two functions other than the unit of time the accept as parameters the function delay() calculates time using the time interript. 10 kHz is a bit fast in my opinion for the. println(time, DEC); delay(1000); takes about 38900 microseconds (or about 39. delay() to return the delay value that was passed to start() Microsecond version of the library. Returns the length of the pulse in microseconds or gives up and returns 0 if no complete pulse was received within the timeout. Share. Using the 100K resistors, with a delay of 10us the readings were consistently 0 and 1023. 9Hz (901mHz) for delay = 555 after HIGH and LOW; when I tried to generate 10. 미래의 아두이노 릴리스에서 바뀔 수 있다. delay (x) will delay for x number of milliseconds. The Arduino programming language Reference, organized into Functions, Variable and Constant, and Structure keywords. Initially, the code will set the servo at 90 degrees. 876 microseconds Got response 3 round-trip delay: 880 microseconds Got response 4 round-trip delay: 1960 microseconds Got response 5 round-trip delay: 4128. Description. For example, if value is HIGH, pulseIn() waits for the pin to go from LOW to HIGH, starts timing, then waits for the pin to go LOW and stops timing. I can't get a second's delay with delay (1000) or delayMicroseconds (1000000) Instead, delay (230000) would give. ) So. Writes a value in microseconds (uS) to the servo, controlling the shaft accordingly. arduino-nano. Currently, the largest value that will produce an accurate delay is 16383. MHz May 14, 2016, 6:14pm 1. The speaker hooks up to pin 1, as the. 1000 microseconds is full left and 2000 microseconds is full right. Anmerkungen und Warnungen. Here is an. If you need multiple tasks to occur at the same time, you simply cannot use delay (). the value returned is always a multiple of four). Ideally, 500ns or less. 7 microseconds. This could change in future Arduino releases. delayMicroseconds() function Syntax The resolution for micros() is 4 microseconds on all 16MHz Arduino boards: Uno, Mega, Nano, etc. This code sets the prescaler to 1024, as slow as you can get. Hello community, I made a function that should be able to create a delay for a certain number of microseconds, here the code. The default timeout for pulseIn() is 1,000,000 microseconds (1 second). 1 or // 2 microseconds) gives delays longer than desired. I wrote some if statements to include _delay_us () for values of 1 and 2 microseconds. For delays longer than a few thousand microseconds, you should use delay() instead. the value returned is always a. 25 uS (ie. However, this would. Syntax. I can't seem to find an elegant. 8. 2 microsecond (High) About a 10 second Delay. The idea is to: Configure the built-in timers to generate a 20 KHz PWM signal. Arduino-ESP32 Timer API. 29 platformioの設定ファイルを「platformio. 2 - LEDs, I used one red and one green. 1 const int trigPin = 2; 2 const int echoPin = 4; 3 void setup() { 4 Serial. realtime clock, microseconds, etc. The following program lets you enter a desired frequency and duty cycle, then. This function works very accurately in the range 3 microseconds and up. Pauses the program for the amount of time (in microseconds) specified as parameter. Para delays mais. delayMicroseconds có nhiệm vụ dừng chương trình trong thời gian micro giây. If you need better resolution, micros () may be the way to go. For this I got a code from Arduino forum which is given below. The Arduino by default does NOT run a "non-real time" scheduler; it runs bare metal code that ought to be very deterministic, except for the occasional timer or UART interrupt that is usually much shorter than RTOS guarantees. Description Pauses the program for the amount of time (in microseconds) specified as parameter. Serial. . There are a thousand microseconds in a millisecond, and a million microseconds in a second. Description. The Arduino millis () is a timer-based function that returns to you the time elapsed (in milliseconds) since the Arduino board was powered up. There are a thousand microseconds in a millisecond and a million microseconds in a second. delayMicroseconds () deaktiviert ab Arduino 0018 keine Interrupts mehr. The Arduino micros () is a function that returns to you the time elapsed (in microseconds) since the Arduino board was powered up. This could change in future Arduino releases. Description. Using simple code to write out the microseconds every delay(1000) I get the following: Zero - Delay Time: 20876. The test I describe below has been done on several boards: Arduino Uno and Arduino nano AT328p. There are a thousand microseconds in a millisecond, and a million microseconds in a second. There are. Set the duty cycle for each PWM signal. Duemilanove and Nano), this function has a resolution of four microseconds (i. (knowing that delay() does not) does millis() and micros() increase as usual while in ISR ? The reason I ask, is that I came over an bigger app, that is very timer-driven (mstimer2) - and it does also read millis & micros for timing - the only way that can be precise, if both are always running. timeout (optional): the number of microseconds to wait for the pulse to start; default is one second. Looking at delayMicroseconds (), it states that for this delay, a maximum of 16383 microseconds is possible for accurate timing. Since interrupts are disabled for the duration of the delay, this will cause a loss of one timer overflow interrupt (delays in excess of 1024 microseconds) for every call to home and clear. cycles = (16,000,000 / 2,000,000) * 60,000,000 = 480,000,000. the value returned is always a multiple of four). Description. I measured the time taken by an analogRead call (without extra delay) at around 110 microseconds. Currently, the largest value that will produce an accurate delay is 16383. Open Serial Monitor. You can use the Servo arduino library, which is very easy to use. TWO - a blocking delay, but one that does NOT use timers (timer0, timer1, or timer2) and is able to work with libraries which have a lot of timing issues or which corrupt millis() or timer0 counts. This could change in future Arduino releases. Pins 0 and 1 are used for the serial port so should be avoided for general IO on a standard arduino board. and, similarly the return value is described as: The length of the pulse (in microseconds) or 0 if no pulse started before the timeout. In the implementation of the function, in the "wiring. Serial communication that appears at. Since delay() requires interrupts to work, it will not work if called inside an ISR. In general, it works already, but the servos are vibrating all the time. g. It will be called regularly. Duemilanove and Nano. Serial communication that appears. //Runtime : 8 microseconds ISR(TIMER2_OVF_vect). When you do delay (1000) your Arduino stops on that line for 1 second. delay () is a blocking function. The macro F_CPU is supposed to be defined to a constant defining the CPU clock frequency (in Hertz). (Hint: rename the class to microDelay and replace occurrences of millis() with micros() ) Freezing/Pausing. Wait(); Reset delay timer right now. The return value for millis() is of type unsigned long, logic errors may occur if a programmer tries to do arithmetic with smaller data types such as int. delay (200) = 2 Hz at the flow computer. Pausa o programa pela quantidade de tempo especificada como parâmetro (em microssegundos). However, we have now increased the number of times we are printing. This function causes a delay in microseconds (μs) instead of milliseconds. 2Hz (200mHz) for delay = 2500 after HIGH and LOW; up until. These values are in microseconds when the timer reach a_value do something. Here is some example code. The Arduino millis () is a timer-based function that returns to you the time elapsed (in milliseconds) since the Arduino board was powered up. microsecond is sent to the station. End Loop. you don't need to start the serial port or SPI interfaces in this instance. Description. From simple blinking LEDs to complex robotic systems, Arduino provides a versatile environment for enthusiasts and professionals to bring their ideas to life. Just like delay () has a microsecond-version called delayMicroseconds (), millis () has micros (). Therefore if you set a tick period of 2ms (500hz) and request a delay of 1 tick you will get a delay of between just over 0 ms (if the request to delay. *; Arduino arduino; int speakerOut = 11;I'm thinking similar to the Arduino delayMicroseconds() function. In reality it's probably a microsecond or two, but the resolution of the micros() function is 4 microseconds. I promise this one is definitely about dual core issues and not my crappy array management. As soon as the transmitter receives the reflected time data, it generates microseconds again. Duemilanove and Nano), this function has a resolution of four microseconds (i. (1000), then the delay will be of 1000 microseconds i. You can also time by microseconds. Currently, the largest value that will produce an accurate. agdl mentioned this issue on Jan 9, 2015. @16Mhz, there are 16 instructions per microsecond. Pauses the program for the amount of time (in microseconds) specified as parameter. e delay(6400) equals to 1 sec delay time. Does the one you quoted do what you want? Here it is written as a regular Arduino function. Wir können nicht garantieren, dass delayMicroseconds () genau für kürzere Verzögerungszeiten funktionieren. g. system November 9, 2008, 9:49pm 1. Check the RTOS documentation to see how to cause a thread to wait. The Arduino programming. They seem incredibly poor in accuracy/consistency and I'm struggling to understand why. delayMicroseconds () is a cycle-counting loop, so it doesn't include any time taken by background functions like interrupts. e. You use it a bit like micros(), except that you have to handle the wraparound explicitly, and because it counts down the subtraction is the other way around. Re: help delayMicroseconds() on esp? Post by dmaxben » Wed Aug 04, 2021 12:36 pm . Central. delay (1) = 494 Hz at flow computer. You just have to know the calling convention. If your servos are just regular servos modified for continuous rotation, the way to control them is to send a 50Hz PWM signal (20ms period) with a high level time between 1ms (full left) and 2ms (full right). 6us. If it's true, how come it is 6. See the LED: The LED toggles between ON/OFF periodically every second. When we try other numbers, it has the same degree of inaccuracy. doesn't work with delays <1 ms. If the time A sends the signal is TSA,; the time. The Arduino code above shows the loop function which, in this case, is the only code required; Make the contents of the setup() function empty as you don't need to initialise anything i. Some interesting info about delayMicroseconds(). Returns Nothing Example Code The code pauses the program for one second before toggling the output pin. For delays longer than a few thousand. **This code works in Arduino with the delayMicroseconds () function. A typical servo uses 1500 microseconds as a center position signal. Duemilanove and Nano), this function has a resolution of four microseconds (i. From the arduino reference page for delay the parameter for delay is an unsigned long. Then you take it high to initiate the trigger pulse, then wait ten microseconds. Pauses the program for the amount of time (in microseconds) specified as parameter. Pito's answer works, but more importantly, do you understand why it works? Also, the #include directive was never intended to be used with source code files (e. These simple Arduino delay functions just wait a fixed amount of time. Ultrasonic ruler with inches, centimetres, and millimetres. Pausa o programa pela quantidade de tempo especificada como parâmetro (em microssegundos). e. Arduino Reference - Arduino Reference This page is also available in 2 other languagesThe Time1. delay(ms) only delays for about 96% of the requested time on Pico and Nano RP2040. Bestimmte Dinge laufen jedoch weiter, während die delay () -Funktion den Atmega-Chip steuert, da die delay () -Funktion Interrupts nicht deaktiviert. 024 milliseconds, then. On 16 MHz Arduino boards (e. While these functions are easy, your program can not do other work. 2 things that come to my mind: -Either the micros() function is not. Currently, the largest value that will produce an accurate delay is 16383. Click the tab to view its contents, including detailed descriptions of the available. On standard servos a parameter value of 1000 is fully counter-clockwise, 2000 is fully clockwise, and 1500 is in the middle. Also keep in mind that the Arduino digitalWrite function is rather slow (it has to map the Arduino pin numbers to PORT/pin), so in your case it would be better to write to the PORT/pin directly. You should explicitly declare your delay value as an. This would mean the delay is limited to a max of 32,767. 8 seconds of delay + 0. Therefore, I need to establish a fixed sampling frequency. August 10, 2020 by garrys. A single I/O instruction is 0. The arduino-esp32 core achieves this using the following code for the delayMicroseconds() func. delay (5) = 100 Hz at flow computer. An exact 100ns delay is not going to be possible with a regular arduino board. Pauses the program for the amount of time (in miliseconds) specified as parameter. For delays longer than a few thousand. Here is the code. Description. /* Delay for the given number of microseconds. One of the best things about Arduino is the ability to just block for a period with: delay (1000); // hang on a second, buddy. set the output LOW PinFlasher f (4,true); // set pin 4 as the output. There are a thousand microseconds in a millisecond, and a million microseconds in a second. In this project I used a timer interrupt to output a sine wave of a specific frequency from the Arduino. Another point, you DON’T need a wait for 33 micro-seconds, but a wait to the next 100 micro-second period, so you just need a 10 kHz rate timer. Arduino0. As soon as you need to do a few things at the same time, you. -1 – counter number 0 so we insert -1 in the formula. Se envía un tren de pulsos de un periodo de aproximadamente 100 microsegundos. On. 23 kHz on pin D9. delay() 関数を使用してコードに遅延を追加し、コード内の出力を確認しました。 micros() 関数の前のコード行を実行するのに 1060 マイクロ秒かかりました。 命令の実行にかかる時間は、Arduino ボードの種類によって異なります。 There are a thousand microseconds in a millisecond, and a million microseconds in a second. Improve this answer. Returns the number of microseconds since the Arduino board began running the current program. millis() is incremented (for 16 MHz AVR chips and some others) every 1. I read other answers before asking this question, but they rely on the time module, which prior to Python 3. The Arduino has three timers – Timer0, Timer1, and Timer2: Timer0 – an 8 bit timer used for the delay(), millis(), and micros() functions; Timer1 – a 16 bit timer; Timer2 – an 8 bit timer; Don’t use Timer0 for interrupts or it might break the delay(), millis(), and micros() functions. Pauses the program for the amount of time (in microseconds) specified by the parameter. Continuing to loop is very important if part of your project is 'listening' for. Description. Use the button connected to pin 3 to increase the angle. However, be aware that micros. println(time); //prints time since program started delay(1000); // wait a second so as not to send massive amounts of data } Notes. It’s only delaying for 8. That is without the time for the iteration/loop. And when in the code it asks for refresh rate *3. 2 - 330-560 Ohm resistors, for LEDs. It sends a. That would be very nice. Currently, the largest value that will produce an accurate delay is 16383. So is there a way I can implement a delay of 1us without using these functions? Thanks in advance 🙂 Description. Blink without Delay - Arduino Tutorial. 11. Auf 16-MHz-Arduino-Boards (z. It is likely that the number being passed to 'delay' is being interpreted as an int. Everything seemed to be working well in my simulations, but whenever I built the circuit and looked at the timing on an oscilloscope all of my uS values seemed to be off. Returns the number of microseconds since the Arduino board began running the current program. Currently, the largest value that will produce an accurate delay is 16383. I have been working on an LED controller that uses a Return-to-zero protocol that requires me to send high and low signals at delays of 0. Arduino Due delay(1) vs delaymicroseconds(1000) #217174. Its hard to see exactly where the time difference is due to not having a scope but I am running an LED. the value returned is always a multiple of four). 0) )) #define SPEED_STATE_WAIT 0 #define. microseconds micros : 10814 HPtimer = 10814 --> 10000 calls of micros() on core 1 (500µs longer) but value measured by the two functions give the same result microseconds micros core0 : 10835 microseconds HighPrecTimer: 10216 microseconds HighPrecTimer core0: 10504 microseconds micros : 10795 HPtimer = 10795. See full list on deepbluembedded. Basically, I found out that delayMicroseconds(x) delays (on Arduino UNO, 16MHz) 7 Clock cycles for (x = 0, 1) 14 Clock cycles Short for (x >= 2) I noticed a too quick delay on 'x = 2' case. vTaskDelay(500 / portTICK_RATE_MS); You can use vTaskDelay () even if not using FreeRTOS tasks. At first I thought this would be fairly simple, but after thinking about it, I have no idea how to code it. The Arduino core uses hardware Timer0 with its ISR (Interrupt Service Routine) for timekeeping. Therefor, I read a lot, especally about xSemaphoreGiveFromISR which seems to be the most efficiant way to deal with this problem. Top. The Arduino framework already includes a function for timekeeping: millis (). Click the "Timer2_Counter_Basic_Example. 1밀리초는 1000 마이크로 초, 1초는 100만 마이크로 초. Schematic view of an Arduino Uno attached to an HC-SR04 ultrasonic sensor. (or Lo and back Hi) Usual fast way is Direct Port Manipulation (vs digitalWrite (pinX,. board. Regards, Ritesh Prajapati. 0. The off-the-shelf micros() function has a resolution of 1/256th of about a millisecond, so pick 4, 8 or 12. See Wait() method. Allowed data types: unsigned long. Microsecond delay within task. Measuring Pulse Width. Hope the info is helpful and maybe others can add new MCU's or tests. CrossRoads: delay (500) delays for 500milliseconds, or 1/2 second. 768kHz clock source, a single. produced a delay of 45 ticks. Two things: you cannot delay for 2 microseconds or 10 microseconds. Instead use Timer1 or Timer2. Hi everyone! I want to implement a timing delay of 1us in my program. I'm struggling to understand how the micros(), millis(), delay() and delaymicroseconds() work on the Arduino Zero. The best way to stop a continuous-rotation servo is to detach it. *; import processing. Currently, the largest value that will produce an accurate delay is 16383. g. My code works but my minimum delay is 880ns (due too the interrupt latency maybe?) and i can only add 1us by 1us. when the timer reach b_value do something. Atualmente, o maior valor que irá porduzir um delay preciso é 16383. Arduinoでパルスを読み取る方法 参考 タイマー割り込みでLEDを点滅させます 変更履歴 2019. I'm not sure if it's a problem with not counting the time instructions in arduino take, but I think it's weird I always get the two same results no matter the distance. com Add Delay in Microseconds in Arduino. Wir können nicht garantieren, dass delayMicroseconds () genau für kürzere Verzögerungszeiten funktionieren. In LiquidCrystal bundled with the Arduino IDE 0016, the functions “clear()” and “home()” use delayMicroseconds to pause for 2000 microseconds. } configura el número de pin 8 para trabajar como un pin de salida. And just changed everything to 500microseconds. Arduino Stack Exchange is a question and answer site for developers of open-source hardware and software that is compatible with Arduino. Description. I'm sorry to have added unnecessary confusion. This tutorial is a simple sketch and circuit to show how this is done. Forum 2005-2010 (read only) Software Bugs & Suggestions. Any delay over 1024us will include timer0 interrupts, and in your example you'll also have serial interrupts. 1000 microseconds is one milliseconds and 1000 milliseconds is one second. It took 1060 microseconds to execute the lines of code before the micros () function.