Which Chip for a Chip Only Arduino Application?

Hi. I have a very simple embedded application that I am working on. I have done lots of projects with several boards in the Arduino line, Teensies, and Adafruit Minis and Trinkets. Now I want to put the micro into a circuit with just the bare necessities. There are several articles and video on "shrinking the Arduino" and I'll use those as a guide but even the ATmega328 has more pins that I need. All I need are one analog input pin and four digital pins.

I would appreciate a recommendation for the right micro that I can use and still develop with the standard IDEs. (I use Visual Studio.)

Thanks very much.

There are several ATtiny chips that would do what you want.

How about an ATtiny85? 5 Pins, 4 of them can be analog input. The only limiting factor is the 8kb memory space.

If you pick the attiny chips I recommend the ATTiny core.

For simple application I like ATTiny13A (only 1 kB Flash, single timer, ADC, comparator).

Of course there are the new feature rich ATTinies.

Sounds like a job for an attiny 85 or attiny 412, depending on what peripherals you need vs flash. 84 or 1614 (1614's peripherals absoluabsolutely bury those of the classic avrs, but you may not need any of them)

Hey thanks for the great replies. I did some looking as well as worked on the design. Of course, as I got into it further, I got into some "technology creep." "If I can do that, well how about I add this feature, and that feature..." That grew the need for more I/O.

If I stay simple, I'll go with the ATTiny85. If I add more features, there is enough room for the ATTiny84.

The project is a model railroading application. For those that aren't familiar with railroading, trains change tracks through a switch or turnout. There are things called "switch machines" that motorize the process of moving the track. Most switch machines are rather big. This is a much smaller one. There is also the issue of handling the polarity of the center portion of the turnout called the "frog". This switch machine will automatically change the polarity of the frog if needed.

Then there is the issue of the signal lights. This is where the extra features come in. I'm not sure if I want to have the switch machine handle controlling signal lights.

Thanks again.