newb here.. 
how do you connect multiple items - (like say 6 different things) to the Atmeg1284P and share power?
like an lcd screen, keypad, mini printer, buzzer and so on?
I don't understand the question. The 1284 doesn't power anything. The 1284 would be connected to the same 5V line that fed all of those other things (assuming that they are all running at 5V).
saying pin wise.. not power.. each item has it's own power recommendations... be it 3.3v to 5.5v
Then each component that needs different voltages will need a different supply. You'll need a 3.3V rail, a 5V rail, and a rail for whatever other voltages you need. The power pin on each device connects to the source that is the right voltage for it. The 1284 will draw its power from the 5V rail.
So you'll need more than one voltage regulator is sounds like.
You just have to make sure that all the grounds are connected together.
i may be a newb, but i highly doubt i would need separate regulators.. considering they pretty much all can run on 3.3 v
insignia:
i may be a newb, but i highly doubt i would need separate regulators.. considering they pretty much all can run on 3.3 v
Well, in reply #2 you indicated that some would be 3.3V and some would be 5.5V. THe 1284 needs 5V. So there are three voltage levels there. That's what I'm going from. I can't see your project or any of the ideas in your head. I can only respond to what you write here.
Either way, the 1284 and your components all get their power from somewhere. They all have Vin or Vcc or some other pin where power comes in and that needs to be connected to a suitable voltage source. None of the power pins on any of your components should be connected directly to the 1284.
1284P can run from 3.3V as well (not like a 2560 that needs 4.5V - while 2560V will run at lower voltage)
1284P Speed Grades
̶ 0 - 4MHz @ 1.8 - 5.5V
̶ 0 - 10MHz @ 2.7 - 5.5V
̶ 0 - 20MHz @ 4.5 - 5.5V
3.3V & 8 MHz would be fine. Need to adjust brown out detection fuse accordingly. See 27.2 Extended fuse bits in the datasheet. Set those when loading the bootloader (you do have a programmer, yes?)
just an arduino.. well.. a clone the like there of..
still don't see how you connect multiple things..
all the tutorials i find only show like 2 or 3 things.. IE: keypad, lcd and buzzer.. what if i wanted to add a mini printer and another component? trying to reduce the number of pins as possible but again i don't see any tutroials showing exactly what i'm trying to accomplish..
looking at like 20 pins.. and 5 gnd and 5 power
I don't understand what the issue here is. 5V comes from somewhere and connects to the top rail of a breadboard. Ground connects to the bottom rail. All of your components connect their 5V pins to the 5V rail and the ground pins to the ground rail.
How many things you get hooked to an Arduino is very dependent on the interfaces and demands of the components you're trying to control. If I hook an 320x480 touchscreen to an arduino, I need about 10 pins. Now suppose I want to hook up a GPS module as well, which might take 4 more pins. Maybe two or three buttons and a few LEDs. An Arduino isn't very hard to max out, either in bandwidth or hardware addons.
As for tutorials on such a topic, just set up the project you want to create, and add components and test the interfaces one at a time. If an Atmega 328 arduino won't get you there, use a bigger one, like the Mega.
I find that Nanos are very very cheap, and I frequently break up the load onto two Nanos. A simple serial link between them can pretty much make them fucntion as one processor, with a lot more pins, memory, and processing power.
But in the long run, you won't start by building Arduino products of great complexity. Get in there and play with the various peripherals you want, then try to integrate them.
You linked to a Mega board.
That one has an onboard 5volt regulator, capable of supplying ~500mA under certain circumstances.
~75mA is already used by the MCU and surrounding parts.
It also has a 3.3volt regulator that can supply ~100mA.
Both supplies can be use to power small things, like sensors and an LCD (shield).
Relays, motors, solenoids, etc. draw too much current, and may need their own supply.
The Mega can still "control" them.
Tell us how you intend to supply the Mega.
Make a list of what you want to connect (links), and we will talk you through it.
Leo..
8 digit 7 segment led display
12 key keypad
buzzer/speaker
mini printer
usb 3 track card reader
i bought this to go with it when ready for the perfboard:
20x4 lcd display
but thinking about buying this to reduce the amount of pins:
all to be powered with some sort of wall power supply..
Hi,
I won't insist on hardware (voltage, # of pins needed, etcetera) concerns . . .
Just one advice: should you have in mind a project that involves all that stuff, go step by step: i.e. first a program with the first display, then the other, then the keyboard, . . . . and so on.
Regards
vffgaston:
Hi,I won't insist on hardware (voltage, # of pins needed, etcetera) concerns . . .
Just one advice: should you have in mind a project that involves all that stuff, go step by step: i.e. first a program with the first display, then the other, then the keyboard, . . . . and so on.
Regards
please feel free to insist.. i would like to hear all advice.. and as far as coding 1 thing at a time.. that's the plan.. 
please feel free to insist.. i would like to hear all advice.. and as far as coding 1 thing at a time.. that's the plan
People that have already sent posts know much more than me . . . By counting pins I'd say that you'll manage with a Mega . .
Reegards
Wawa:
You linked to a Mega board.
That one has an onboard 5volt regulator, capable of supplying ~500mA under certain circumstances.
~75mA is already used by the MCU and surrounding parts.
It also has a 3.3volt regulator that can supply ~100mA.Both supplies can be use to power small things, like sensors and an LCD (shield).
Relays, motors, solenoids, etc. draw too much current, and may need their own supply.
The Mega can still "control" them.Tell us how you intend to supply the Mega.
Make a list of what you want to connect (links), and we will talk you through it.
Leo..
right now i want to code and wire up everything with my arduino mega 2560.. but eventually i want to transfer everything onto a perfboard.. whatever makes it work has to be put onto the perfboard so it is a standalone unit without my arduino mega attached.. as for power - in the end it will be a wall power supply
I'm wondering how you will integrate the 'usb (3 track) card reader' with your Atmega1284P?
Whandall:
I'm wondering how you will integrate the 'usb (3 track) card reader' with your Atmega1284P?
i bought this to put onto the perfboard:
maybe i have the wrong part here? but i know currently you CAN use the arduino USB for it.. so somehow it can be done on a perfboard as well..
maybe use something like this on the perfboard?
right now, i just want to know how to connect it all to the arduino.. and surely the arduino does not have enough pins.. so can somebody please tell me how to minimize say 20 pins or more to the arduino - based on the 6 different components as mentioned?
USB 3 TRACK CARD READER:
usb connection
5v - ASSUMING.. that's what i've read
KEYPAD:
gnd, power, 5 pins
+3.0V to +5VDC
LCD Display:
gnd, power, 14 pins? unles it uses one of these: http://i.ebayimg.com/images/g/Q4UAAOSwNSxVeRI-/s-l1600.jpg.. then gnd, power, 2 pins
5v
BUZZER/SPEAKER:
gnd, power, 1 pin
3.5 to 5.5V
8 DIGIT 7 SEGMENT DISPLAY:
gnd, power, 1 pin
5v
MINI PRINTER:
gnd, power, 3 pins
5 Volt to 9 Volt regulated DC power supply that can provide 1.5 Amps or more during high-current printing