Flash Atmega 328 without Arduino Dock

[Last Call]

Hello togehter,

i try to flash a hex file to a Atmega328 (installed Arduino Bootloader) without the use of the Arduino IDE.
First try: Use Arduino Dock --> send hex file to omega --> flash .hex file --> Flash works
Next step: Take this omega and place it on an Onion Breadboard Dock and wire a Arduino Mini based on this instruction: https://docs.onion.io/omega2-docs/arduino-dock-2.html. Try to flash again -->

What could be the problem?
ResetPin: The Onion Arduino Dock uses a transistor to pull the Atmega Reset to Ground but Omegas Pin 19 goes to 0V shortly after starting the flash. So I thougt it should work without that transistor. Additional i tried to push Reset by hand.

SPI Connection: I do not use any level shifter but run the mini on 3.3V.

Atemga328: Is there a special script running on the atmega on the Onion Arduino Dock?

Do you have a hint for me?

Thanks.
Kind regards.

[György Farkas]

@Last-Call said in Flash Atmega 328 without Arduino Dock:

i try to flash a hex file to a Atmega328 (installed Arduino Bootloader) without the use of the Arduino IDE.

The Arduino Bootloader doesn't do anything here.

Next step: Take this omega and place it on an Onion Breadboard Dock and wire a Arduino Mini based on this instruction: https://docs.onion.io/omega2-docs/arduino-dock-2.html.

I think you are talking about the "Omega to ATmega MCU Connections" table.
You have to connect only these pins now:

Omega2 pins    ATmega pins
GPIO 15        SPI SCK
GPIO 16        SPI MOSI
GPIO 17        SPI MISO
GPIO 19        /Reset via an Open Collector Inverter (eg. an NPN transistor;)

ResetPin: The Onion Arduino Dock uses a transistor to pull the Atmega Reset to Ground but Omegas Pin 19 goes to 0V shortly after starting the flash. So I thougt it should work without that transistor. Additional i tried to push Reset by hand.

Connect GPIO 19 to /Reset without an OC inverter / NPN transistor is not a too good idea.
If configure GPIO 19 to be an output and set it to High and short the /Reset to GND
then you create an overcurrent condition on the GPIO 19 and it may be destroyed.

If you - even so - want to connect GPIO 19 to /Reset directly then you have to modify the '/usr/share/arduino-dock/avrdude.conf' file.

Additional i tried to push Reset by hand.

I think you should let the avrdude to manage the ATmega's /Reset pin.

SPI Connection: I do not use any level shifter but run the mini on 3.3V.

If the Vcc of an ATmega328P is 3.3V then the clock frequency can be max. 10..11 MHz.
Although - if you are a lucky man - then your Arduino will work @3.3V also with a 16 MHz Xtal.

Atemga328: Is there a special script running on the atmega on the Onion Arduino Dock?

No - avrdude and all related scripts are running on Omega2.

Good Luck!

[Last Call]

Hey György,

oh man... that wasn´t worth to open a topic... I just grab a NPN and it works. Thank you very much.