Re: Support for ATTINY827, 1627 and 3227

[Konrad Rosenbaum]

Hi,

On 15/02/2023 19:39, tony@montgomery-smith.org wrote:
> Thanks for your response.
>
> I don't think the avr8-gnu-toolchain needs to be recompiled. As far as 
> I can see, it just needs the addition of iotn827.h, iotn1627.h and 
> iotn3227.h to avr8-gnu-toolchain-win32_x86\avr\include\avr. For 
> earlier chips, the necessary info was in the datasheet in Register 
> Summary. But this info is missing for the newest chips.
The compiler needs those header files, the linker needs some basic 
pre-compiled code. Both of them also need descriptions/scripts that tell 
them how the chip works. All of those can be found in the compiler packs 
you can download from Atmel.

http://packs.download.atmel.com/

You add some parameters to compiler and linker calls:

GCC: -B /location/of/pack/gcc/dev/attiny827 -isystem 
/location/of/pack/gcc/dev/attiny827/include

LD: -B /location/of/pack/gcc/dev/attiny827

-B tells them where to find the chip descriptions and linker 
instructions, -isystem is the include file location; you need to set the 
correct base path of the pack and replace "attiny827" with the correct 
chip name

> The authors of avrdude must have had access to more info than in the 
> datasheet to add these chips.
It's all in the datasheet. Check it out - it's over 500 pages long!

https://ww1.microchip.com/downloads/aemDocuments/documents/MCU08/ProductDocuments/DataSheets/ATtiny1624-26-27-DataSheet-DS40002234B.pdf

The information that is important for AVRdude is in chapter 7 "Memories" 
and 31 "UPDI".

The programming interfaces of those chips are pretty uniform, if you 
know what location to write to you are basically golden once you have 
the protocol available.


    Konrad

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