Week 6 Journal – Controllers

A controller I’ve been looking at for several weeks now is the Atmel ATtiny24A. What is this and why am I interested in it? I’m glad you asked!

The ATtiny24A is the tiny little brother of the bigger ATmega328 and ATmega168 used on most Arduino boards. It’s smaller and weaker, but just like your little 1-week old baby brother, it still has all the same functioning parts and speaks the same language (well, if babies could speak). How tiny is it? If you get one in surface-mount packaging, it can be as little as 3mm square, or about the thickness of two nickles.

(not the actual ATtiny24A, but close)

That smallness is important, because a side project I’m working on, a pocket-sized Ethercon cable tester, only allows a PCB of 20mm square, on which I need to fit most of the electronics.

Fine, it’s little, but what does it DO?

  • 8-bit AVR
  • 20 Mhz
  • 2 Kbytes Flash memory
  • 12 I/O pins

Compared to the ATmega chips used in Arduino boards, the primary differences are less flash memory and fewer I/O pins. The code required for my tester is minimal, and I need 9, possibly 10 I/O pins.

Out of all the chips out there, why am I picking this particular chip? Because it’s an AVR chip, and can use the same code as the Arduino, and can even use the same Arduino compiler for programming the chip, if you follow instructions listed here and here. Is it the *best* chip to use? Probably not – it’s capable of doing more than is needed and costs 3 times as much (ATtiny24A chips can be had for 60-70 cents in quantities of 100, while smaller chips can be had for under 20 cents). But, those smaller chips would require me to learn assembly, and I don’t have time for that right now. I already know Arduino programming, somewhat, so, I’m using what I know.

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4 Responses to Week 6 Journal – Controllers

  1. Frank Mason says:

    I love that no matter what, technology just keeps finding ways to get smaller. Maybe one day, technology will become so small there will be components on a device that are there by which we cannot see with the naked eye, but it is just a thought. How will you be using this particular micocontroller in your future project?





    I found a website and some videos that could help you to gain some more information about microcontrollers and however you may want to use them, I hope it helps.

    • I’m pretty sure there already are components that exist at the millimeter and even nanometer scale. And I’m certain there exists components that are smaller than we can see with our own eyes! Even on some consumer devices, I sometimes have a hard time seeing LEDs — until they’re on and they’re incredibly bright. If it wasn’t for the plastic packaging surrounding those LEDs, they basically wouldn’t be anything more than spots on the board.

      For my project the controller is just sequencing through 8 wires, making sure there is electrical continuity. It theoretically can be done using simpler electronic components, but all the ones I’ve tested that way had one flaw or another, while the microcontroller always got it right.

  2. Yaro says:

    Cool controller! I wonder, how is it mounted on a PCB? I don’t see any pins at all. Does it go into a special socket, like a memory card?

    • If it’s one of the SMD chips, it’s actually just held on with solder – a special solder paste is applied to the board, the chip is put on top of the solder, and then the board is baked in an oven (or a special heat gun is used) to melt the solder. It’s possible to do by hand, but is considerably more difficult than through-hole technology.

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