Re: Support for ATTINY827, 1627 and 3227

[Konrad Rosenbaum]

Hi,

On 21/02/2023 11:59, dvalin@internode.on.net wrote:
> Apropos the last two words above, I've had a bit of a google for a
> windoze-free path to the programmed ATmega328 needed for an UPDI
> interface, but haven't figured that out yet.

Could you please clarify: is your goal to use an AtMega328 AS an UPDI 
progger to program a DIFFERENT chip? Or do you plan to program the 
AtMega328 USING UPDI?

The AtMega328 uses the ISP protocol (based on SPI) to be programmed. 
That's what your STK500 can speak.


If you need a cheap progger to program a true UPDI chip (eg. 0-series 
AtMegas, various modern AtTinies), simply do this:

1) Get a cheap USB-serial-TTL dongle from your online electronics 
discounter of choice. The TTL part is important. (There are plenty of 
CP210x, FTsomething, and CH340 based designs out there. And they are 
really cheap.)

2) Connect a 1kΩ resistor to the Tx pin of the dongle.

3) Connect the other side of the resistor and the Rx pin directly to the 
UPDI pin of the target chip.

4) Use GND and Vcc(*) out directly to power the chip while programming it.

5) Tell AVRdude to use a "serialupdi" progger (because that's what you 
just hacked together).

(*) Many of those cheap dongles have a 5V and a 3.3V output, make sure 
you use the same level as the Tx pin (it outputs high while idle, so 
simply use a multimeter and compare). The chips are usually quite okay 
with being powered with either voltage while being programmed.

This "hack" is surprisingly reliable. I've been using it for quite a 
while now and it never failed to program my chips. I even made myself a 
"professional" looking PCB that incorporates all of that using a CH340N 
and a few simple SMD components.


> Does anyone have a link to
> a Linux-only guide, just using the gnu toolchain & avrdude? I.e. no
> arduino dev environment hocus pocus. (I have an old Atmel STK500 for
> programming the interface ATmega.)

What exactly are you looking for?

If you have an arduino sketch that you need to push to a chip: using the 
Arduino environment is really the easiest way, since it adds a lot of 
libraries and #include guesswork (a'ka hocus pocus) to the translation 
process. The good news is: you can install arduino from its official 
download on Linux without contaminating other environments, it just sits 
in a separate directory and is quite happy there without installing 
stuff elsewhere. So cleaning it up is just deleting this arduino 
directory (and perhaps the "sketch" directory) from your home directory.



    Konrad

OpenPGP_signature
Description: OpenPGP digital signature