Arduino Mega 2560 connection

[grogcw]

Hi !

I tried to use my Arduino Mega board (one of the firsts rev. I think) and I'm having issues :

I compiled thru Arduino project and uploaded the code, I think this part is fine as the board's led is slightly lit (probably waiting for a usb<->serial signal).

My setup is the following :

Attiny402 -> PA0(UPDI pin) -> 4K9 resistor (close enough) -> Arduino Mega board header PWM pin 6

The Arduino's auto-reset is disabled via a 100uF capacitor across reset and GND. Attiny's Vdd and GND are connected to 5v and GND on the Arduino Mega board supply should be ok).

I installed avrdude, and using this command in jtag2updi folder (the port can seem wrong, but it's the right one using MacOS) :

avrdude -C avrdude.conf -c jtag2updi -P /dev/cu.usbmodem143411 -p t402

... I've got either of these two logs :

avrdude: jtagmkII_reset(): timeout/error communicating with programmer (status -1)
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.

avrdude: jtagmkII_close(): timeout/error communicating with programmer (status -1)
avrdude: jtagmkII_close(): timeout/error communicating with programmer (status -1)

avrdude done.  Thank you.

... or ...

avrdude: jtagmkII_getsync(): sign-on command: status -1

... in loop so I have to kill it (by Ctrl-C).

Maybe the pin I connect the UPDI pin is the wrong one ?

Thanks for taking care and for this awesome project,

Cheers !

[ElTangas]

Unfortunately, this software is not compatible with the ATMega 2560, the MCU that powers the Arduino Mega. Probably, the program would be easy to adapt, the problem is that I don't have an Arduino Mega to test it :-(

[grogcw]

If you need anything from me considering that I have quite an experience with electronics, access to the Mega's board schematics (including the nets and pads of the MCU) along with some MCUs to burn (literally), there's no problem. :)

If you consider it would be an hassle to adapt, you can close this issue.

No hard feelings, I also understand that.

Cheers !

[ElTangas]

It should not be difficult. Probably only the file updi_io.cpp needs to be modified. I'll work a bit on it then you can test it (in a week or so, I think).

[ElTangas]

Ok, the test version is almost ready. I will use the code provided by contributor cbalint13 for the Arduino Mega port. I'm adding some configuration options which will make the code easier to port to other devices.

[ElTangas]

I created a test branch: https://github.com/ElTangas/jtag2updi/tree/Experimental-Arduino-Mega-compatible

Note that the binaries on the build folder are for the mega328p, as usual. To test for the Arduino Mega, you will need to build a proper binary. You can use either the Arduino IDE, which is automatic if you select the Arduino Mega, or edit and run a makefile. I've set the UPDI pin to be D3 (TX1/ pin 18 on the Arduino Mega) but you can change it by setting the UPDI_PORT and UPDI_PIN defines. Note that UPDI_PORT must be in the A-G range, higher ports are not supported.

Please test it and if everything is fine I will commit to master.

[grogcw]

All right, I'll check this tomorrow :)

Thanks for the workaround !

Cheers !

[ElTangas]

Weel, I'll close this and merge Arduino Mega experimental version to main.