[Arduino Mega Pinout
Betty Neyhart
My Arduino program uses port registers extensively (PORTB, PORTD, etc). Currently, I am merging the work of several Arduino Diecimilas onto one Arduino Mega but I can't find any conclusive information about how the Mega Pinout corresponds to the higher port registers (PORTE, PORTF, etc). I see the port registers referenced on the 1280 data sheet and in the Arduino AVR code libraries, but could use some assistance.
For example, look at the top right corner of the 1280: You'll see a group of 8 pins, ATmega pins 71 through 78. These are labeled PAn, where n is 0 to 7. These are the individual pins of PORTA, along with their corresponding signals (conveniently labeled PAn as well). Now look to the right a bit at JP1, and you'll find these signals again. The green text tells me these are arduino pins 22 through 29.
i'm looking for some "basic" information on pinout for this particular board that i believe anyone with some basic understanding and experience with arduino and this particular board can answer, that i can not, not at the moment without intensive research, for which i do not have the time at the moment.
so PLEASE, don't understand this as me being lazy to look it up! i'm just requesting an answer if you are already have the knowledge, i'm not asking others to do my work!! but im in a building stage and this information is needed to place the wires at the right pins, whicnh needs to be done now. all other work will be done in a few months or a year time, when i can research but for now i need the wires to be at the right place.
the arduino part is only a small part of a (for me) large project of years now that i need to finish. all the rest can be done later. yes maybe this is in the wrong order.. but at this moment it is a necessity.
SDA and SCL pins:
there is a print on the board that SDA is pin 20 and SCL is pin 21 but those pins are digital pins while on genuine arduino boards the SDA and SCl are analog pins (4 and 5) or seperate SDA and SCL pins.
spikey1973:
2) SDA and SCL pins:
there is a print on the board that SDA is pin 20 and SCL is pin 21 but those pins are digital pins while on genuine arduino boards the SDA and SCl are analog pins (4 and 5) or seperate SDA and SCL pins.
about the pmw pins, i had an idea it might.. but as it says 15 pmw's and 2-13 is only 12 pins so i thought i had to be wrong with that assumption. any idea where the other 3 could located then? i only need one, and due to placing the excess to those ports are to say at the least trouble some.
my analog pins are all in use, and digital ports are accessible from pin 16 on, so i hope i can use another as such, this would make me really happy as it is basically the last issue i have before i can move on.
indeed also the mentioning of the 16u2 chip in the name confused me, together i kinda assumped that is sort of simulated the mega by adding a second chip. kiving it all the same options, but leaving me in doubt on the pin structure.
i now understand now that has nothing to do with it, and the mega itself also has this 16u2 chip so it really doesn't make a difference what so every (that is how i understand it. please correct me if i'm wrong)
The ATmega2560 uses serial communication for getting uploaded sketches and communication with the Arduino IDE Serial Monitor (e.g. Serial.prinln()) but most computers these days don't have a true serial port. Nowadays we use USB to connect devices to our computers. The ATmega2560 is a very nice microcontroller but it doesn't have any USB capabilities. For this reason a separate chip is usually added to Arduino boards that acts as a bridge between the serial communication of the ATmega2560 and the USB of your computer. The computer then creates a virtual COM port that makes it seem like your board is connected to a serial port on your computer even though it's connected via USB. The ATmega16U2 is a microcontroller that has native USB capabilities so it can be programmed to act as a serial-USB bridge.
Typically the only reason you will need to think about this chip is if you need to install the correct drivers for it in order for your board to be recognized by your computer. The Arduino IDE comes with the drivers for the ATmega16U2 and FT232 so usually you will only have troubles with that if you get one of the clone Arduino boards that use the CH340 (that's the cheapest of the three chips so it's quite common on the cheap clones).
There are some Arduino boards that use microcontrollers with native USB capabilities. These boards do not require a separate bridge chip, they can communicate directly over USB. The most common are the Arduino Leonardo and the Pro Micro.
it is intended to use the rotary encoder to set the light intensity of a ledstrip (ws2812b strip) manually, as the apperatus will be used in the dark as in light. therefor one would want it brighter or dimmer according to the circumstances, maybe i can do an automatic adjustment. but ifso i will also have this manual override.
the coding and actually getting things to work will be a long time from now, the main thing is to get the hardware ready to be fully assembled. then i can use a second board with a test setup to get things working with the wires in the same place, but before i can do that i need to be sure that things will work with the way it is wired.
as access by then will be very complex, and i'd rather avoid that at all.
as also said i have some major limitations with the pins i can use, for now you've been a saving angle, as all pieces have fallen together, just realized though that there maybe one final issue, the interrupt in this code, as for now i have only one available., with some effort i can get a 2e one available but i rather not, so if i don't need to i won't
I put a spreadsheet together that shows arduino pins to atmega2560 ports and atmega2560 ports to arduino pins
I've put it in the playground in interfacing with hardware / general (right at the bottom)
By the way someone already placed a arduino pins worksheet on the google spreadsheet site, showing pins assignments for both the 168/328 chips and 'mega' chip, which in the arduino world means both the mega1280 and mega2560 chips which share the same pin assignments.
Well to edit or convert it I would have to be able to open it, right? I don't have open office on my machine, I'm sure that is the case for lots of the forum members. I'm not trying to put down your effort, it is appreciated ( I think, can't open the document), just that you consider making it avalible in a more common document format.
I've created an updated version that removes what you rarely need (IC pins), ordered it by port and added the colours from the mega pin diagram. I've also included the diagram and IC for reference.
In doing so i found a mistake on Chris's version (pins PF0/1 were reversed)
Perhaps this can be posted in place of the old version on the playground -moderator?
Hi! I am very new to kicad and just created and ordered my first pcb
For my seond project i would like to create a arduino mega shield.
I found a pcd layout thru google that has all the pins in correct place
But how can i assign this to the correct footprint. There is no file that i can find
So i thought i just draw the pcb route tracks but the pencil will not snap to the pbc points.
All advice is more then welcome!
What we have here is the actual conductor number in the grey background (counting the conductors in the ribbon cable from left to right) and then above and below them the corresponding signal lines according to the above pinout. Above and below the signal lines I have noted the actual Arduino pins that correspond to the signals.
So we have to connect signals D0 through to D15 to the necessary digital pins. Then we also have to connect pins RS, WR, CS and REST to whichever pins we like (we must declare these pins in our sketch, see UTFT documentation). Pin 11 is RD and it must be pulled high, which means connecting it to +3.3V. Pin 37 is the backlight illumination which means it must also be connected to +3.3V. This leaves pin 1 which must be connected to ground and pin 3 which must be connected to Vcc which in our case is 5V.
Now, there is one more thing that I should point out and it is very important. The Arduino MEGA is using 5V logic while the TFT is expecting 3.3V logic. This means that if you connect the D0-D15 and RS, WR, CS, REST lines directly to the MEGA you will most likely damage the TFT. You need to connect a 10K resistor in series with each and every one of the lines. That will bring the voltage down to acceptable levels. Do not forget to do this!
Would you mind showing your pin interface? or send me an email with some type of picture or diagram with it? I think buying the shield is pointless because i have more going on with my arduino than just a TFT, I would appreciate any help you could give!
It is definitely not the best way of doing things but it limits the current just enough so that it does not cause damage. A more proper solution would be a voltage divider built with 2 resistors, but that would not be easy to do without a PCB. The best solution would be to use level shifting ICs, but we would definitely need a PCB for those.
To be totally honest, IMHO the best solution would be to retire the MEGA and go for a DUE.. 3.3V logic and fast as hell which is particularly useful when driving an LCD. Also practically same price with the MEGAs.
While Arduino Nano is a breadboard friendly version of Arduino UNO with more or less the same features, Arduino Mega is completely a different board. It can be considered as a big brother to both UNO and Nano, both in terms of size as well as features.
As you can notice, there is a Type-B USB connector on the left short edge of the board, which is used for powering on the board as well as programming the Microcontroller. There is also a 2.1 mm DC jack to provide external power supply. Apart from that, the layout of Arduino Mega is very much self-explanatory.
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