Hi,
I use AVR128DA28 (or higher pin count variants of that chip) for
development and testing - breadxavr:nsh gives you configuration that has
NSH. The documentation page is at
https://nuttx.apache.org/docs/latest/platforms/avr/avrdx/boards/breadxavr/index.html
If you want to try it at some point, the page has a schematic of simple
circuitry needed to interface PC side UART with chip'a proprietary
programming interface (UPDI). It is supported by avrdude as well.
As for the ostest mentioned below - if you get to running it (on either
this chip or the 2560), please let me know how it went. I tried some
basic utilities like ls on this one and did not get very far (hit what
looked like a memory corruption.)
On 2026-10-04 17:06, Tomek CEDRO wrote:
Thank you KR, and what AVR chip do you use in your projects and
testing the release? I will try to align :-)
--
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info
On Sun, Oct 4, 2026 at 9:54 AM <[email protected]> wrote:
Hi,
if I was trying to do this with a DYI solution while aiming for single
USB connection, I'd have a look at something based on FT2232H from
FTDI.
Dual channel serial device, in UART mode by default but can switch
(among others) to SPI which is used by both ATMEGA128A and ATMEGA2560
for program memory programming.
If I am not mistaken, both of those chips could also be powered from
3.3V output of the FTDI - albeit not with highest clock with the 2560.
Avrdude on the PC side for uploading the program.
I am not familiar with any AVR boards except for their name in NuttX
configuration so can't tell you if there is a solution the can be
bought
and used out-of-the-box.
As for what is the most popular chip for use in NuttX - no idea. The
arduino-mega2560 was chosen to be covered by MemBrowse Memory Report
but
IDK what was the reason to pick that board specifically. There is
pretty
much no development activity in arch/avr so can't judge much from that
either. If someone wanted me to recommend AVR chip for new design, I
would certainly recommend the new generation (AVR128DA28 etc.) but
support for that family was added last year so there is little chance
that it is the most popular one.
I believe Alan was trying to run NuttX on one of the older supported
chips last year but as far as I know, could not make it work. Don't
remember which chip was that though.
Btw. if I remember correctly, the AtMega256 has a bug in NuttX - one
of
the I/O registers that facilitates access to program memory addresses
higher than 16 bits is not stored in process context. The other chips
with 128kB of flash are not affected. So I would probably not use that
one for any tests that are designed to try to break things.
On 2026-10-03 11:37, Tomek CEDRO wrote:
> Hello world :-)
>
> I am looking for hints on how to quickly connect AVR device over
> single USB connection to have flash and shell connectivity to my test
> suite.
>
> I have several bigger devices but only as cpu module bare bones on a
> pcb so no interfacing even no power supply: ATMEGA128A and
> ATMEGA2560.
>
> Which AVR devices are most popular on NuttX? If not 128 or 2560 but
> some inexpensive board with flash+shell link onboard then I will get
> one please let me know :-)
>
> Any hints welcome :-)
> Tomek
>
> --
> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info
