RE: Building with an MCU

Robert Peter Oakes — Fri, 05 Dec 2014 03:52:05 GMT

This should help re programming the ATTiny85

http://www.instructables.com/id/Program-an-ATtiny-with-Arduino/

regards

Peter

RE: Building with an MCU

bobcroft — Thu, 04 Dec 2014 09:15:29 GMT

David,

This should answer part of your question, taken from the official Arduino web site;

There are three pools of memory in the microcontroller used on avr-based Arduino boards :

Flash memory (program space), is where the Arduino sketch is stored.
SRAM (static random access memory) is where the sketch creates and manipulates variables when it runs.
EEPROM is memory space that programmers can use to store long-term information.

Flash memory and EEPROM memory are non-volatile (the information persists after the power is turned off). SRAM is volatile and will be lost when the power is cycled.

The ATmega328 chip found on the Uno has the following amounts of memory:

Flash 32k bytes (of which .5k is used for the bootloader)

SRAM 2k bytes

EEPROM 1k byte

So if you decide to use another processor then you need to look at its Flash memeory capacity for > 6.25K in your present project.

I believe it is possible to program the ATtiny series via an UNO acting as an ISP (In System Programmer) although I have never done it. A 'Google' search will usually bring up the information you are seeking.

An alternative is simply buy a cheap clone UNO and use that but I get the impression you want to build a controller from scratch. Again there is plenty of information on minimal circuits for the ATmega and Attiny processors. Usually you just need the chip, crystal oscillator and a few capacitors. You can also use the internal oscillator on the 328 instead of an external crystal if you want to go really minimal.

The minimal circuit configurations lack the ability to program the device via USB so you would need to program the devices via a fully configured UNO used as an ISP. Alternatively you could use a dedicated programmer.

To my mind these alternatives require a lot more effort than using a cheap clone.

Best of luck.

Bob