attiny85 as a micro controller without ftdi or another avr board to program it?

Hello i been looking for a more smaller board to fit one of my project. And what i came across was a Attiny85 board with USB on it no FTDI or another board programming it. I was wondering if it is possible to do this? I never saw or head of using a attiny85 like this. I have seen the atmega32u4 that requires no ftdi on it or anything else.

I found this board on ebay. http://www.ebay.com/itm/5X-PCS-Digispark-Kickstarter-Attiny85-USB-Development-Board-for-arduino-/221898923514?hash=item33aa34ddfa:g:W-0AAOSwo6lWJaDh

I'm wondering how is this possible?

arduino does not need usb serial adapter or external isp programmer if it has a usb connector and self-program bootloader. t85 digispark is one of the early and most popular examples and there are many variations and clones. mega series chips can also do it like in this recent thread: http://forum.arduino.cc/index.php?topic=404035.0.

one drawback is the bootloader take up memory which can be a handicap on small chips like those. another is, unlike serial or isp, the need to press a button every download which is very inconvenient for productivity fiends like me. there are work arounds but sometimes the cure is worse than the disease. for me isp is the key for tiny and mega.

josephchrzempiec:
<…>
I’m wondering how is this possible?

Trinket and DigiSpark are both tiny85 and have USB.
The USB is provided by code originally written by ObDev generally known as V-USB.

Trinket and ProTrinket are Adafruit products but the V-USB bootloader firmware comes from the same dude that designed and programmed the USnooBie stick. Frank Zhao is one of the lesser known but IMO still great brains in the Arduino movement.

Ray

mrburnette: USnooBie stick. Frank Zhao is one of the lesser known but IMO still great brains in the Arduino movement.

ah yes... another (not quite so) flatduino. when will these guys get down to REALLY flat form factor. and realize weee doe need no steeeeenkin' PCB.

soviet igor cesko, the true father of soft usb, is even lesser than lesser known but deserves the real credit. i recall many years ago struggling for months trying to get his early versions running. it wasnt until years after that atmel adopted igorplug as an app note that progress was made.

soviet igor cesko, the true father of soft usb, is even lesser than lesser known but deserves the real credit.

I'm enlightened! Just read his post.

Thx,

Ray

Thank you all for these comments. It is awesome to see that arduino can be program some other way besides using a FTDI or ch340 chip. Gives me a lot to think about for a future project thank you.

Get one of these:

https://www.sparkfun.com/products/9825

It's really useful for all my tiny projects (I use it with ATTiny85, '45 and '84 processors.)

josephchrzempiec:
Hello i been looking for a more smaller board to fit one of my project.
<…>

I would exercise some reasoning when considering smaller … that does not necessarily mean less power provided you have a little room in your concept of “smaller.” You first need to consider your application needs.

Ray

Left --------> Center -----> Right:
ProMicro, ProMini, Trinket
2.5K SRAM, 2K SRAM, 0.5K SRAM

Flicker

ChrisTenone: Get one of these.

It's really useful for all my tiny projects (I use it with ATTiny85, '45 and '84 processors.)

Interesting to note - in relation to another thread here - that the page specifically explains that they have not mastered the 2560 code.

(So it's just fine for the Tinys. :grinning: )

Good to know Paul. Thanks for the link.