Does the 16U2 come with firmware pre installed?

Other Hardware 3rd Party Boards
1

Hello,

I have made a prototype using basically a stripped down version of the UNO (16U2 and 328P, see attachment) with some LEDs on it and a 3.7V battery. I used a guy to make a PCB layout and ordered an assembled version but the USB is not working for communication (just battery charging), not even showing up in OS port list of my mac. I have an ICSP header which programs is 328P but the 16U2 does not have a header. So my questions is:
does the 16U2 come with firmware pre installed?
if not the I guess i have created a brick :frowning:

Thanks for reading,
Markus

Schematics.pdf (1.13 MB)

2

The 16u2 does not come with any firmware pre-installed. :frowning:

3

I have made a prototype... ordered an assembled version

Why did you not discover this problem when you made your prototype, before you ordered an assembled version?

4

The prototype was made with a real UNO and that of course has a working 16U2.

5

Ah, too big a gap between the prototype and the assembled version.

6

You might be able to do something with sharp pogopins...

You can probably bypass the 16u2 with some other USB/Serial converter, and/or use ISP programming to program the 328 directly. So ... not quite a brick.

7

Luckily I do have ICSP headers to program the 328P but cannot do any serial prints for debugging - so it's not a total loss. Leaned something: don't just trust anyone who 'has does this before'...

8

In the atmega328 boards I have constructed, I always use a commonly available usb-serial adaptor module to program and debug the board. I use female pcb headers on the main board so the adaptor can be removed when not needed.

Also if I plan to solder the atmega direct to the main board, I will add ISP header in case I need to update the bootloader or program it that way. Otherwise I use a chip socket so I can remove the chip if I ever need to update the bootloader or program it using ISP rather than serial programming.

usb serial adaptor.jpg
usb serial adaptor.jpg1600×1600 84.8 KB

usb serial adaptor.jpg
usb serial adaptor.jpg1600×1600 84.8 KB

9

Have you tried the Atmel FLIP programmer software?

You may be able to program the chip via USB. I use 32U4. It comes with DFU firmware so it shows up on PC device manager. Not sure about macs.

10

that looks promising! can you well me what pins on the 16U2 are actually connected via the 10k resistor shown on the UNO R3 picture?

11

Launching the default DFU loader pre-installed on 16U2 is easy.

With the HWB pin (is PD7) pulled down to GND, simply reset 16U2 with the RESET pin.

Connect 16U2 to your computer via USB.
Using a needle-like probe, connect pin 13 to GND via a 1K ohm resistor.
In that state, touch pin 24 to GND for a moment via a 1K ohm resistor.

OK, The DFU loader will be start: Your computer recognizes 16U2.
You can then use the corresponding any tools to program the firmware.

Note:
The QFP package has a narrow pin to pin clearance.
Be careful of short circuits on other pins when working.
However fortunately, referring to your schematic, both sides of the HWB pin are unused.
And the RESET pin is on the corner of the chip.

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