Could I upload a .hex file to my Atmega16u2 using a Teensy 4.0?

My Arduino UNO won’t go into DFU mode and I am going to by another one at some point to flash the DFU enabled bootloader onto it. I’ve seen people load .hex files and flash bootloaders onto the atmega16u2 using a variety of Arduino products and I’ve only seen a few people do those task using a Teensy 3.0. I only have a Teensy 4.0 (and my UNO) but I haven’t seen anything one the 4.0 despite it being released in August 2019. I’ve tried multiple times in trying to “convert” instructions on wiring Teensy and Arduino boards to one that would make sense using a Teensy but nothing has worked. Though I am aware that buying a Leonardo or a Nano or some other board would be easier, I just don’t want to find out I could do something else to make my life easier. I am currently using the Teensy 4.0 as a programmer for the Arduino UNO but due to the lack of help the internet has given me, IDK how to do it.

TL;DR: Noob want to know if Teensy 4.0 can be used as an ISP programmer for a atmega16u2 micro-controller so he can upload a .hex file or flash DFU mode enabled firmware onto said micro-controller

:confused: P.S if this is the wrong forum could someone kindly direct me to the correct one? THX :slight_smile:

I don’t own a Teensy 4.0, but I would expect you could make the connections:

Teensy ATmega16U2
MISO MISO
MOSI MOSI
SCK SCK
10 Reset
3V +Vcc
G Gnd

Upload the unmodified File > Examples > 11.ArduinoISP > ArduinoISP to the Teensy.

Be sure to not power the Uno separately while you’re doing this. The reason is the Teensy is a 3.3 V device, while the Uno is 5 V. You don’t want to expose the Teensy to 5 V.

Here’s the pinout of the ATmega16U2’s ICSP header:

Pin 1 of the ICSP is near the AREF pin. There will probably be a little dot on the silkscreen next to it.

I don't know the exact specs of the '16U2, but an ATmega328P doesn't run reliably at 16MHz/3.3V.

You may need to run the '16U2 at 5V and use level shifters to connect to the Teensy.

That being said, there's a good chance the '16U2 is dead if it doesn't want to reset into DFU mode anymore.

Pieter

Devoted_Eves:
My Arduino UNO won't go into DFU mode and I am going to by another one at some point to flash the DFU enabled bootloader onto it. I've seen people load .hex files and flash bootloaders onto the atmega16u2 using a variety of Arduino products and I've only seen a few people do those task using a Teensy 3.0. I only have a Teensy 4.0 (and my UNO) but I haven't seen anything one the 4.0 despite it being released in August 2019. I've tried multiple times in trying to "convert" instructions on wiring Teensy and Arduino boards to one that would make sense using a Teensy but nothing has worked. Though I am aware that buying a Leonardo or a Nano or some other board would be easier, I just don't want to find out I could do something else to make my life easier. I am currently using the Teensy 4.0 as a programmer for the Arduino UNO but due to the lack of help the internet has given me, IDK how to do it.

TL;DR: Noob want to know if Teensy 4.0 can be used as an ISP programmer for a atmega16u2 micro-controller so he can upload a .hex file or flash DFU mode enabled firmware onto said micro-controller

:confused: P.S if this is the wrong forum could someone kindly direct me to the correct one? THX :slight_smile:

For what it's worth, my Atmel AVR-ISP MK-II can program a 16u2 just fine.

Therefore, if you have a working ICSP of any kind, it should work.

Whether or not there is any difference between "DFU mode" and ordinary programming I do not know.