Okay, I found and played with RobotDyn Mega 2560 PRO (Embed) /
Atmega2560-16AU chip [1], it has onboard CH340 for flashing that works
with avrdude, just additional UART2USB board is required, using as
Arduino-Mega2560, builds fine, flashes fine, runs fine so far with
only bare nsh no commands no ostest, will add board and ostest config
if that fits in 8K RAM :-)
Also need to review config because that bare nsh shouold not use 71KB
of flash :-)
avr-gcc (GCC) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
% /usr/bin/time -h ./tools/configure.sh -B arduino-mega2560:nsh
% gmake CROSSDEV=avr-
(..)
Memory region Used Size Region Size %age Used
flash: 71642 B 256 KB 27.33%
sram: 2718 B 8 KB 33.18%
eeprom: 0 B 4 KB 0.00%
2,06s real 17,83s user 7,04s sys
[1] https://robotdyn.com/mega-2560-pro-embed-ch340g-atmega2560-16au
% avrdude -v -V -p atmega2560 -c wiring -P /dev/cuaU0 -D -U flash:w:nuttx.elf:e
Avrdude version 8.2
Copyright see https://github.com/avrdudes/avrdude/blob/main/AUTHORS
System wide configuration file is /usr/local/etc/avrdude.conf
User configuration file is /home/XXX/.avrduderc
Warning: programmer xplainedmini_twi fails to specify prog_modes =
PM_...; [/usr/home/XXX/.avrduderc:357]
Using port : /dev/cuaU0
Using programmer : wiring
AVR part : ATmega2560
Programming modes : SPM, ISP, HVPP, JTAG
Programmer type : Wiring
Description : Wiring bootloader using STK500 v2 protocol
Programmer model : AVRISP
HW version : 15
FW version controller : 2.10
SCK period : 0.1 us
AVR device initialized and ready to accept instructions
Device signature = 1E 98 01 (ATmega2560)
Reading 71642 bytes for flash from input file nuttx.elf
in 1 section [0, 0x117d9]: 280 pages and 38 pad bytes
Writing 71642 bytes to flash
Writing | ################################################## | 100% 22.19s
71642 bytes of flash written
Avrdude done. Thank you.
% cu -l /dev/cuaU1 -s 38400
Connected
NuttShell (NSH) NuttX-13.1.0
nsh> uname -a
nsh: uname: command not found
nsh> help
help usage: help [-v] [<cmd>]
? help
nsh>
:-)
--
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info
