Hello Fellow Arduino Fans,
I have been working a lot with the ATtiny85 lately and recently designed a easy-to-use prototyping board which makes it easy to use on a breadboard and program via ISP. ATtiny85 is a great way to port your smaller Arduino projects over to the low-cost ATtiny85 chip.
What makes the ATtiny85 ISP! more powerful and different than other similar ATtiny85 based projects, is that it does not require a bootloader. Some bootloaders for the ATtiny85 take up to 2K of flash memory, when the ATtiny85 only has 8k to begin with. Using ISP solves this issue and allows the user the full 8k of flash, plus the ability to change clock speeds and set fuses at will.
Anyways, if you are interested in checking out my project I have it up on Kickstarter where you can help the project and receive a full version of the board or kit! Link is here:
The best part about this project is that it will be released to the Arduino community under an Open Source Hardware license. The moment the project is successfully funded, the design files will be available for download.
Thanks for checking out my project!
I've thought about this one a lot... prior to your thread.
The perfect attiny85 tool consists of...
An atmega surface mount with a preloaded (or diy) arduino as isp, 1 micro usb interface (to upload your attiny sketches) and aziff socket to prevent damage from over use.
Step 1. Insert attiny into an attiny85.
Step 2. Set to arduino as isp, etc etc.
Step 3. Upload.
Take attiny85 out, anywhere anytime.
Thanks for the reply! That is a cool idea you have, and I did think of those options but there are some challenges to be dealt with the idea as you described:
- There is not a ZIF socket available in 8 pin (that I have seen) 14 pin is the smallest
- Each time you want to program the ATtiny85, you will have to pop it out of your breadboard, into the ZIF, and back again (lots of wear on the pins)
Futhermore, as you probably know, it is difficult to program the ATtiny85 via ISP when it is a circuit unless the pins are isolated by high value resistors from the rest of your project. With the ATtiny85 ISP! you simply can just pop the entire board out of the breadboard, upload the sketch, and pop it back in. When you are satisfied that your programming is OK, you can take the chip out of the 8pin DIP socket and embed it into your project and put a fresh one in.
Also most ISP programmers (USBtinyISP etc.) have built in +5v power from the USB port, so when your ISP cable is hooked up to the prototyping board, you do not need to supply power (unless your circuit draws more than the 500 mA the USB can supply to the programmer and your project)
Got my Kickstart Reward ATtiny85 ISP and made it Blink. (Feb. 2013). Had some difficulty with older tutorials etc on programming the ATtiny85 using my UNO R3(clone) as an ISP. Success via download of 1.5.5 IDE and ATTiny files including cores from here:
Made the /hardware/tiny folder in my Sketchbook and things went OK from there after copying the tiny folder from the link above (version: arduino-tiny-0150-0020.zip). You have to have a boards.txt file as described in readme. Used ATTiny85 internal 8 MHz board option and left heartbeat delay at 20 in the ArduinoISP sketch from 1.5.5.
Some older How To & references to ATTiny programming with an Arduino as ISP had folks reverting from 1.0.x IDE to 1.0.1 or even earlier environments. One ref. said Uno wouldn't work. One had the change in heartbeat that was not necessary any more. Looks like the Uno and 1.5.5 are good to go for ISP programing of the ATTiny85. Worked w raw chip and with the ATtiny85 ISP board. I used the LEDs on pin 7,8 and 9 as per the Arduino ISP sketch directions for additional visual clues.
As noted elsewhere "On the Arduino Uno, you'll need to connect a 10 uF capacitor between reset and ground "
Hold Shift to download using programmer in IDE, as Ben noted. Ordered a ISP shield before I got my Uno working w the most recent IDE and the ATtiny 01500-0020 above. Oh well, will likely be easier to use and give me a nice ISP 6 pin cable...