USBtiny is not a USB-Serial device, it is its own USB protocol which is understood by Avrdude. You will not see a COM port or Serial port created when you plug it in.
Any AVR that uses the ISP interface for programming and has 64K or less of flash can be programmed.
Chips such as the Atmega1280/1281 and Atmega2560/2561 have more than 64K and cannot be programmed.
Chips that use TPI interface, such as Attiny4/5/9/10 cannot be programmed.
Some very old chips such as the AT90S1200 and similar cannot be programmed
- Put a fresh AVR chip (such as an Atmega328) into the Arduino in the correct orientation
- Remove the jumper from the USBtinyISP
- Plug in the USBtiny to USB
- Plug the Arduino into DC or USB so it is powered
- Plug the 6 pin cable from the USBtinyISP into the Arduino so that pin 1 mark is lined up with the red wire on the cable
- Start up Arduino IDE
- Select the chip/Arduino you are using in the Tools->Board menu
- Do not select a COM/Serial port
- Select Tools->Burn Bootloader->w/USBtinyISP
- The USBtinyISP red LED should light up. It will take a minute or two to program the chip
- When it is done, the IDE will tell you it has completed and the red LED will be off.
The USBtinyISP design as-is only works with the AVR core chips (ATtiny/ATmega/etc). However Lucas Chiesa and his peers have done an excellent job porting this version to support 8051-core chips.