Hi,
shortly i need io expander (24 channels) and i found that barebones mega are dirty cheap, but i never used bare bone arduino.
Things that must be done for barebone uno doesn't look hard but how about mega? Is it just repating all steps that were needed for barebone uno or there will be some complications? I would love to make my own gpio expander (it would be cheaper and i would have few pwm channels available).
Does anyone made standalone mega? Was is as simple as uno?
I can use following microprocessors: ATMEGA4809-PF, ATMEGA8515L-8PU, ATMEGA16A-PU, ATMEGA164A-PU
That is a subjective question. It can range from quite easy for some of people on this forum to impossible to others who do not even know what a soldering is. It is entirely dependent on the person doing the assembly etc and the skill set and resources they possess.
If I were to take a SWAG I would assume from your question it would be difficult but not impossible for you do do it.
Where do you expect a difference?
I'd think it's all alike. Enough caps to stabilize the operating voltage, quartz/resonator and Reset according to the data sheet.
Afterwards handle the different pins for programming as required. If you want to use the Arduino framework then make sure that your board pinout resembles the Mega or write your own board variant file.
IMO, building a Mega (ie ATmega2560) is much harder because it's a pretty big fine-pitch SMT chip.
(If that doesn't bother you, then it's NOT "much harder.")
If you meant one of the 40-pin DIP chips you listed (which would NOT be an "Arduino Mega"), then yeah, those are pretty similar in difficulty to an Uno. The ATmega4809 needs a different programmer, though.
Yes, i was thinking about DIP ones. Sorry i assumed all atmega with so many pins can be named 'mega'. I just care about having at least 24 output pins and be able to use IDE to program it
But after spending again half hour trying to understand that topic i feel only less sure about it, so i think i'll pass and just use MCP23008-E/P and some diffrent io expander that can handle PWM.
I think there was some confusion. There is "Mega AVR", encompassing a wide range of "ATmega*" chips (many available in DIP), but there is also the "Arduino Mega", a "big" board that uses ATmega1280 or ATmega2560 chips, both of which are 100pin chips available only as SMT.
I don't want to order pcb right know, i'm making big project and i want to order one big motherboard when i will be 100% sure about everything (so after year of running 24/7 without damages/malfunctions). It connests two mcu with each other and a lot of mosfets (with mostly inductive loads), my own i2c device, dozens of sensors and on top of that it mixes digital and analog signals, and uses wifi... - it's a lot of places where something will go wrong, especially because i'm learning everything on the fly
Thanks for help, i'll stick with already-made io expanders. Good u answered, because i was close ordering one and right know i would propobly be frustrated because I hate software problems when problem doesn't lay inside code I wrote (like picking correct programmer and finding why it's not working), especially when there is little to nothing begginer-friendly tutorials online
