Upload to AtMega4809 on Arduino Uno WiFi2 fails

[Virtual-Java]

After downloading the extension packages from microchip, compiling the hex file worked for me. Unfortunately uploading to the Arduino Uno WiFi fails reproducibly (Programmer is not responding). Previous the IO-MCU on the board was flashed with Optiboot via the onboard UPDI Programmer running on the AtMega32u4 USB-MCU. For my tests the AtMega4809 is connected via the UART pins broken out to pins D0 (RX) and D1 (TX) to another Arduino Uno (without a processor in the socket) being used as a USB to UART converter. I have checked my connections several times, so the hardware should do its job. But maybe my settings for the fuses are wrong?

Compiling Optiboot for "Mega0 AVR boards": 1.) Download Atmel.ATmega_DFP..atpack.zip from Microchips website (e.g. Atmel.ATmega_DFP.1.7.374.atpack.zip from http://packs.download.atmel.com) 2.) unzip Atmel.ATmega_DFP..atpack.zip to any directory and remember the path to it (e.g. \~/Downloads/Atmel.ATmega_DFP.<newest.version>.atpack_Files) 3.) export the path and adapt the path in all makefiles when using make scripts like makeall.mega0.sh (e.g. export PACKS=\~/Downloads/Atmel.ATmega_DFP.1.7.374.atpack_FILES) 4.) compile for the new Atmega devices either manually or by running makefiles (e.g. make -f Makefile.mega0 UARTTX=C4 LED=D6 atmega4809 or . makeall.mega0.sh 5.) NO error messages caused by missing packs should appear during compilation!!!_

  _Bootloader size with skeleton App   text data bss dec hex filename   04      9      0   513   201 optiboot_atmega4809.elf     avr-size optiboot_atmega4809.hex   Bare Bootloader size   text data bss dec hex filename      0   466    0   466 1d2 optibootatmega4809.hex

6.) Rename the created files: for most linux distros like Arch:'rename optiboot_atmega4809 optiboot_atmega4809_UnoWiFi2 optiboot_atmega4809.* for Ubuntu derivates like Mint: rename 's/optiboot_atmega4809/optiboot_atmega4809_UnoWiFi2/;' optiboot_atmega4809.* 7.) create custom hexfile directory: mkdir ../../hexfiles/mega0_custom 8.) move UnoWiFi2 files to hexfiles directory: mv optiboot_atmega4809_UnoWiFi2.* ../../hexfiles/mega0_custom/ 9.) test image by uploading it to Arduino Uno WiFi Rev2:

10.)Backup the fuses and flash memory (dump flash): Optiboot/compile_optiboot_gcc5_4/original-github/optiboot/optiboot/hexfiles/mega0_custom$ ~/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/bin/avrdude -C ~/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf -v -p atmega4809 -c xplainedmini_updi -P usb -D -U fuse0:r:fuse0:b -U fuse1:r:fuse1:b -U fuse2:r:fuse2:b -U fuse5:r:fuse5:b -U fuse6:r:fuse6:b -U fuse7:r:fuse7:b -U fuse8:r:fuse8:b -U flash:r:optiboot_atmega4809_UnoWiFi2_dump.hex:i

11.) My commands to BURN Optibootloader: AVRdude burn custom Optiboot bootloader: \~/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/bin/avrdude -C \~/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf -v -patmega4809 -cxplainedmini_updi -Pusb -Ufuse0:w:0x00:m -Ufuse1:w:0x48:m -Ufuse2:w:0x01:m -Ufuse5:w:0xC9:m -Ufuse6:w:0x07:m -Ufuse7:w:0x00:m -Ufuse8:w:0x02:m -Ufuse9:w:0xC5:m -Uflash:w:optiboot_atmega4809_UnoWiFi2.hex:i

12.)RESTORE original bootloader dumped from flash previously (works): Arduino IDE burn original mEDBG bootloader: \~/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/bin/avrdude -C \~/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf -v -patmega4809 -cxplainedmini_updi -Pusb -Ufuse2:w:0x01:m -Ufuse5:w:0xC9:m -Ufuse8:w:0x02:m -Uflash:w:\~/.arduino15/packages/arduino/hardware/megaavr/1.8.7/bootloaders/atmega4809_uart_bl.hex:i

Q1:) FUSE VALUES: are they correct??? -Ufuse0:w:0x00:m Watchdog timer window and period mode are disabled -Ufuse1:w:0x48:m BODLEVEL2 2.6V; SampleFreq 1kHz; Sampled in Active and Idle Mode only -Ufuse2:w:0x01:m Oscillator calibration at runtime is possible; internal oscillator running at 16MHz -Ufuse3DONTWRITE RESERVED -Ufuse4DONTWRITE RESERVED -Ufuse5:w:0xC9:m no CRC Source; RESET pin; keep EEPROM during chip erase -Ufuse6:w:0x07:m 64 ms startup time after power on before code execution -Ufuse7:w:0x00:m append is at flashend otherwise size of bootsection + appsection (rest unused) -Ufuse8:w:0x02:m bootend is 512 Bytes (256 words) from flashstart -Ufuse9:w:0xC5:m device is open, reading all memories is possible Q2:) ERROR: "fuse9" memory type not defined for part "ATmega4809" WHY???

Q3:) Why is my arduino USB-MCUs Serial number FFF… Programmer Type : JTAGICE3_UPDI Description : Atmel AVR XplainedMini in UPDI mode Serial number : FFFFFFFFFFFFFFFFFFFF Vtarget : 5.00 V

Since I spent a lot of time to research the information how to compile Optibootloader for the AtMega4809, I decided to describe my procedure very detailed to simplify the steps for other people.

Because I am not sure how many mistakes I made, I will definitely correct them afterwards. Please tell me if I should change my original post as far as possible or post an improved short guide. Maybe I can spend some time in writing a file for make atmega4809-isp, when the fuses are clear.ed:)

[WestfW]

I don't understand...

uploading to the Arduino Uno WiFi fails reproducibly

Uploading, how?

RESTORE original bootloader dumped from flash previously

Isn't the original bootloader only for OTA updates, via the wifi module (which is on a different UART than pins0/1) It also uses a different protocol than optiboot, based on AN2634

[WestfW]

For my tests the AtMega4809 is connected via the UART pins broken out to pins D0 (RX) and D1 (TX) to another Arduino Uno (without a processor in the socket) being used as a USB to UART converter. UARTTX=C4

Ah. That and your fuses seem correct. Have you changed your board type to reflect that you are uploading using optiboot? What was the actual avrdude command line that was issued for the upload?

[mcuee]

Maybe this is related. https://github.com/arduino/ArduinoCore-megaavr/issues/119