ATtiny85 how to program without bootloader

Hello everyone!

I know this might be answered somewhere but whatever i found online and tried had no success. Since im new to that i cannot combine info from different tutorials etc.

I have an arduino nano and a mega(missing the cable for mega so lets forget that for today, everything is closed due to coronovirus) and a YSUMA01-341A which i found on my old room and it seems to be usb to serial etc.

From what i read online, dont know if im wrong, but to program an attiny85 with arduino as programmer i need to burn bootloader to my chip. Which is something id like to avoid for now.

So using my usb serial board how to program my attiny85 using arduino IDE?

For now I only managed to download attiny boards for arduino IDE from

Please find attached the settings i have on my arduino IDE.

Thanks everyone in advance

Best Regards,


Burning a bootloader to the tiny85 can do 2 things. It can install firmware to enable programming via Serial and set the fuses for the chip setup. You do not have to install the serial programming software, but the fuses must be set if the chip is to be used with anything other than the factory defaults for oscillator and other options.

So using my usb serial board how to program my attiny85 using arduino IDE?

The bootloader cannot be installed with serial, it must be installed with the ICSP pins. See this page (done with an Uno, but uses the same pins on a Nano).

I prefer the SpenceKonde ATTinyCore. In my opinion the ATTinyCore is easier to use and has better functionality.

Hi. Thanks for your info. What does it mean to set fuses for chip setup? Thank you

Perhaps this tutorial can explain what the fuses do and how and why that they are set.

The "fuses" are a small area of memory - 3 bytes on classic AVRs like the t85 and '328p - which configure basic operation of the part - what clock source it uses, whether to enable BOD (brown-out detect - resets the chip if the voltage goes below minimum), whether to retain the EEPROM data when an ISP programmer does a "chip erase" cycle, stuff like that.

Classic AVRs, from the factory, come set to run off the 8MHz internal oscillator divided by 8 for 1MHz (this is done because it is in spec over the whole range of operating conditions the chip is rated for). People generally want to set them up to run at 8MHz (for most ATtiny's - though the t85 can run at 16MHz internal as well).

The fuses can only be set via ISP programming. I will note that (at least in the US - maybe not all countries) online stores are running normally - and that's where you go to get ISP programmers anyway (I like the USBAsp - though you can also use other Arduino's running ArduinoISP sketch. The Arduino IDE only sets fuses when you choose "Burn Bootloader" - my ATTinyCore (linked above) has two options for most families of parts in the Tools -> Board menu:
A normal one, which assumes ISP programming will be used - I generally recommend this method for most ATTiny parts - with no bootloader, where "burn bootloader" just sets the fuses and erases the flash. Upload will try to use the selected ISP programmer to upload the sketch.
An Optiboot one, which has a serial bootloader. This takes up some of the flash, but allows programming over serial - once you "burn bootloader" with an ISP programmer, you can wire it up with the "DTR reset" circuit (see the readme of the ATTinyCore docs, or google) and a serial adapter for programming over serial. With the optiboot board definition selected, this is what it will try to use when you choose upload.

thanks everyone for the replies.

This is what i found in my room


I can see SPI so i can program it with this programmer also right? When i plug it in i get a new com port.However how to connect it to my chip and what settings shall i put in Arduino IDE?

PS in greece everything is closed so im trying to use only what i have atm

appreciate everybody's help

I can see SPI so i can program it with this programmer also right?

Very doubtful.

You said that you have a Nano. Why not use the Nano to program the tiny85 using ICSP programming and the Arduino as ISP example?

I have not heard of people using adapters like that with avrdude. Certainly theoretically 100% possible. But no idea if avrdude supports that adapter. Certainly no programmers.txt entry for it.

After googling around, not finding relevant tutorials except this thread - I want to share my hesitation about this mini board:

It looks like it meant to be used to program the ATTiny 85 even for the first time, but I can't see on it any clue of a chip that can be used as a programmer.

I don't know if the micro-USB connector is intended just for 5V power, or it can be connected to the computer running Arduino IDE and to upload the sketch using it (without another ISP connected).

If someone knows this board or have any clue about this it would be really appreciated.