Atmega16u2 & Atmega1284p

I'd like to build my own Arduino clone board using the Atmega16u2 with a Atmega1284p but I'm having a hard time finding any firmware that supports both. This article makes it sound simple using Atmel Flip, but the filenames of the firmware indicate you have to choose one for a 328/16u2 or 2560/16u2 combo.

The 328 doesn't have enough GPIO for my project, but the 2560 is overkill. In doing research about flashing a 16u2, it seems as if the firmware is designed to work with only a few chips, and the 1284p is not one of them.

Considering the complexity involved with flashing brand new chips ordered online, I'm also leaning towards using a 1284p with an FTDI FT232, essentially building my own FTDI Basic into my board. Its design requires a continuous USB\Serial connection so I can send commands from a PC running nanpy (I'm coding everything in Python). I've successfully used an MCP2221A with an Atmega328 to control a board with nanpy, but now I want to be able to use SMD components and therefor I can't swap chips liked I use to do with my custom board and a official Uno to download sketches.

So my questions are: - Is it possible to use the 16u2 with the 1284p? - is there any advantage to using either the 16u2 over the FT232? Or vice versa? - Can I use Atmel Flip to flash everything? Or do I need AvrDude?

BTW, I'm new to flashing and bootloading fresh chips. I've only ever bought pre-flashed 328s to build the one Arduino board I've made. But I'm at the point where I need to make changes to the design and upgrade to the 1284. But I'm unsure if it's possible.

Worse case scenario is I just use the 2560. But that takes up more board space and cost more than a 1284p.

Any advice would be appreciated.

Thanks!

Look at my Arduino variant variant with ATmega1284P. |500x364

Your questions: - Is it possible to use the 16u2 with the 1284p? Definitely. Any ATmega which is able to upload code via serial. You can use UNO board with removed chip connected to 1284P as test.

  • is there any advantage to using either the 16u2 over the FT232? Or vice versa? My experience is that the FTDI is better for less error producing serial transfer.

  • Can I use Atmel Flip to flash everything? Or do I need AvrDude? I have no experience with Flip since the averdude solve all my needs.

Thanks for the reply. I think I'll order both an FT232 and 16u2 and try both out.

How do you plan on programming the 16U2?

I'll wager that the same f/w used on the 16u2 on the Uno or the Mega will work just fine, and that the only "issue" would be that it shows up as an Uno or Mega in device manager.

I would use a CH340G - dirt cheap, SOP-14 is easy to solder, and minimal external components, and a dead-simple circuit.

I prefer FT232 myself. Can get a MIKROE483 module from Mouser to install on the board, and wire up an FTDI Basic header in parallel for when you want the connections for programming but don't need the onboard USB connectivity.

I have several 1284P boards available, see if any will fit your needs. http://www.crossroadsfencing.com/BobuinoRev17/ |500x209

There is also an FT231XS-R

https://www.digikey.com/products/en?keywords=768-1129-1-ND

Which cost a little less than the FT232RL

https://www.digikey.com/products/en?keywords=768-1007-1-ND

The main reason I use FTDI is that it has a VID/PID which I am allowed to send to a customer. Having said that I would dump the USB and use an adapter like CrossRoads is showing. I have started using a Raspberry Pi's hardware UART connected with level conversion to the AVR, and it is making me think that not having USB hardware is going to be more appealing as these single board computers become more popular.