![]() On Rev1 boards: connecting the solder jumper on the back of the board (near the map of Italy) and then resetting the 8U2.The ATmega16U2/8U2 is loaded with a DFU bootloader, which can be activated by: The ATmega16U2 (or 8U2 in the rev1 and rev2 boards) firmware source code is available in the Arduino repository. You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header using Arduino ISP or similar see these instructions for details. It communicates using the original STK500 protocol ( reference, C header files). The ATmega2560 on the Mega 2560 comes preprogrammed with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. For details, see the reference and tutorials. ![]() The Mega 2560 board can be programmed with the Arduino Software (IDE). You can find here your board warranty information. Need any help with your board please get in touch with the official Arduino User Support as explained in our Contact Us page. Need Help?Ĭheck the Arduino Forum for questions about the Arduino Language, or how to make your own Projects with Arduino. You can find in the Getting Started with Arduino MEGA2560 Rev 3 section all the information you need to configure your board, use the Arduino Software (IDE), and start tinkering with coding and electronics.įrom the Tutorials section you can find examples from libraries and built-in sketches as well other useful information to expand your knowledge of the Arduino hardware and software. If you are looking at upgrading from previous Arduino designs, or if you are just interested in boards with similar functionality, at Arduino you can find:įind inspiration for your projects with the Mega 2560 board from our tutorial platform Project Hub. The Mega 2560 is an update to the Arduino Mega, which it replaces. The Mega 2560 board is compatible with most shields designed for the Uno and the former boards Duemilanove or Diecimila. It contains everything needed to support the microcontroller simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. It has 54 digital input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. Int.The Arduino Mega 2560 is a microcontroller board based on the ATmega2560. Note: Beware the mismatch in interrupt numbers used on MEGA2560 versus the ArduinoĪttach/DetachInterrupt commands, as follows: Is 1/10000sec (100µS) so we get our result in just 100µS. We deduce the frequency by multiplying theĬounts between the leading edges by 62.5.Īn advantage of this method is the quick calculation. By using no prescaler the timer countsĮvery clock cycle (62.5nS at 16 MHz). Timer 3 is a high-precision 16-bit timer. * Frequency counter using Timer 3 to work out the interval (i.e wavelength)īy counting between two consecutive rising interrupts (leading edge) on pin D18 (int3).īased on Nick Gammon's similar program for Atmel 328P processor, here:Īdapted for MEGA2560 by Chris Jennings. If anyone is interested, here is the code: #define CJ_ID "Wavelength2560 version:C" So my listing of the numbering mismatch above seems to be correct. Since posting I adapted my code to use timer/counter 3, interrupt 3 and Attach/DetachInterrupt 5, and it works perfectly on my MEGA2560. I have yet to try using Attachinterrupt(5.) and timer/counter 3, but will do so if my understanding above proves correct Interestingly when I convert Nick Gammons example from interrupt 0 to interrupt 5 with the signal on D18 it does read the frequency correct, but only on the first reading. This suggests that if I use AttachInterrupt(5,isr,rising) with the signal coming into D18 I am actually using MEGA interrupt 3 and Timer/Counter 3 !Ĭhecking the MEGA2560 pin mapping further suggests the true mapping is: So I decided to use int.5 on pin D18 but then I noticed that maps to pin 46 on the MEGA2560 chip ("PD3/TXD1/INT3") But in trying to convert it to run on a MEGA 2560 I came across what appears to me to be an Interrupt numbering mismatch between those used in the Arduino AttachInterrupt / DetachInterrupt commands and the ATMEL numbering for the MEGA 2560.Īccording to the Arduino reference the Mega2560 mapping is: I tested on my UNO first and it worked just fine. This is the example that works by counting the interval between rising edges. I am working with "Another Frequency Counter" program in Nick Gammon's excellent notes on Timers and Counters ( Gammon Forum : Electronics : Microprocessors : Timers and counters).
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