Can I programm Attiny85 directly from FTDI

Hi All , I ordered couple ATtiny 85 chips from Aliexpress , and they sits here thinking what to do with it ,

in short I have FT232 FTDI programmer + the ATtiny 85(10 of them ) other boards I have is STM32 (2) and Digispark ATtiny 85 usb chip , All videos/tutorials I watch talk about using Arduino board to programm ATtiny chip ,

anyway I wounder if it possible to programm the chip directly via FTDI programmer direct (after upload Arduino boot to it ) .

If you use my core (board manager url in sig), there is a serial bootloader (use the (optiboot) board def).

But you will still need an ISP programmer or arduino running Arduino as ISP sketch to bootload it (usbasps and nano clones are both 3 bucks or so on ebay/aliexpress, either is suitable).

You will also need a 0.1uf cap and 10k resistor for the autoreset circuit so the serial adapter can reset it into the bootloader. (Also, dont forget that you also need a 0.1uf ceramic cap between power and ground close to the t85 ti ensure reliable operation; without this the chip may behave erratically depending on circumstances - I mention this because it is very often omitted in designs I see here, particularly with tinies. You always need this for digital ICs unless otherwise specified in the datasheet. With the t85, if on breadboard or protoboard, i usually put this across the top of the chip to minimize the distance between cap and chip)

Thanks @DrAzzy for the helpful reply , I know now I need Arduino as ISP to burn the bootloader , but I read comment (on other sellers page ) already have Arduino bootloader comes with ship , if that Is the case (I I found another way to burn the bootloader) Could I upload sketch to ATtiny85 directly from the FTDI ! ..... BTW I'm thinking using STM32 as ISP ( of course after I figure out how ) , It's my fault I bought many boards and forgot buying the important one (The Arduino board )

There is no official bootloader for the t85 - it is not an official board, and there is no "official" bootloader.

The most common t85 bootloader is the vusb/digispark/digistump one, which requires a few external components, connects directly to USB, and requires the digispark core (my core has more and better features), and eats a whopping 2k of flash (1/4th of the flash on the t85 - leaving only 6k for your sketch; the serial bootloader my core includes only takes 640b).

I would not be surprised if chips were available pre-loaded with the digispark bootloader - though be aware if you are thinking of getting such pre-bootloaded parts, they sometimes disable reset on them to get an extra I/O pin - if that has been done, you cannot reprogram them with ISP, only via the bootloader. HVSP programming is required to undo that.

Honestly, for the t85 (and other parts with 8k of flash or less without a hardware UART), I recommend not using a bootloader at all, and just programming them via ISP. Bootloaders on parts without hardware UART are always kind of janky, as are bootloaders on parts without hardware bootloader support (basically all classic-avr* attiny parts with a couple of exceptions). You get more flash, and you don't have to worry about what the bootloader might be doing on startup messing up your setup. I only use bootloader on the 841, 1634, and 828 out of the classic attiny - the rest I just program via ISP.

I'm not sure off the top of my head if the STM boards can be used as ISP - I don't see anything immediately obvious in the arduinoisp sketch that would cause a problem, but I never hear of people doing it on these forums. People almost always use a USBAsp, USBTinyISP (both are under $5 shipped, get the 10p-6p adapter for the USBAsp if you go this route), or a classic AVR based arduino like the Uno/Nano/ProMini running the arduinoisp sketch (nano and pro mini clones are also under $5). I usually use USBAsps, though I have a nano with the ISP wires an 10uF cap soldered onto it (wires glued to the back with hot-glue - this keeps them from breaking off during handling, without it they break very easily right where the solder meets the wire) as a dedicated Arduino as ISP programmer.

  • as opposed to megaavr, like the ones my megatinycore supports - ones where the part number ends in a 0 or 1 followed by a 2, 4, 6, or 7 - these all have a hardware uart and bootloader support.

DrAzzy:

Thanks @DrAzzy for this valuabe reply again , What I like about t85 is their small size and amazing power consumption ~2 mA , I really want to learn programming these Microcontrollers and create my own project with'm ,(On in my mind was mini WlkiTalki similar to what I saw on Youtube ). Back to subject I'm 100% agree with your suggestion using ISP to programm this chip , my MC's testing lab messing a lot of components I'm trying to build list of it and buying it at once .

DrAzzy: (Also, dont forget that you also need a 0.1uf ceramic cap between power and ground close to the t85 ti ensure reliable operation; without this the chip may behave erratically depending on circumstances - I mention this because it is very often omitted in designs I see here, particularly with tinies. You always need this for digital ICs unless otherwise specified in the datasheet. With the t85, if on breadboard or protoboard, i usually put this across the top of the chip to minimize the distance between cap and chip)

Excellent advice!

FYI, this is how I bypass parts like the T85:

https://www.instructables.com/id/Zero-Real-Estate-Bypass-Capacitor-for-Prototype-C

It avoids having to solder to the chip itself or doing an ugly "under the board" tack on of a capacitor.