AT90USBxxxx vs FTDI

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All

pardon my ignorance but I'm developing some projects with USB interfaces. And I was wondering why everyone seems to be using the FTDI products when the AT90USB and ATMEGAxxU4 controllers have USB built in.

It seeems that several people have also complained about the added cost of the FTDI's.

This even gets down to the suppliers (dk and mouser) having virtually no stock of the AVR USB devices.

Is it that they are fairly new and don't have momentum yet? Or is there some technical reason that in my ignorance I don't understand?

Thanks
Chris

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The FTDI chips are a no-brain solution. They do USB->serial and have drivers that work on most computers. They require no specific software on the AVR part to operate. The USB AVRs on the other hand require you to have a USB stack ( a group of s/w routines) to support the USB function. Depending on how you're implementing the USB device, you may need to write specific drivers on the PC side - most people just implement standard devices to avoid this.

Overall, using the USB AVR devices would probably make for a cheaper overall solution, but there's more work involved and you have more flexibility.

Choose your poison.

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Thanks Kartman

In one of my projects physical size is critical. I'm not frightened of s/w solutions (i'm primarily a software guy) and there is plenty of example code around. So it looks like thde USB AVR's are the go

Only problem is getting my hand on a supply of some of the higher end USB AVR's for prototyping. Maybe the 162 will do the job.

Chris

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Do check out my LUFA stack for the USB AVRs:

http://www.fourwalledcubicle.com

It's pretty simple to use, supports the entire USB AVR range, and comes with a giant pile of prewritten demos for most of the standard classes which you can pull apart and extend from. Makes working with the USB AVRs dead simple.

- Dean :twisted:

Make Atmel Studio better with my free extensions. Open source and feedback welcome!

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Hi Chris
I have used both

I have implemented the USB stack in assembler on the AT90USB64, the reason for using this chip is that I wanted to implement Midi using class drivers.

I have also used the ftdt devices as serial ports or fifo parts, they are great if you want to use their drivers.

Let me know if you want a copy of my code

Regards

Colin

I am an assembler freak, I use HLL on DAW's but assembler on embedded processors. I using ATmega128, ATUSB90 and now XMega.

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Thanks Dean and Colin,

Dean I've already seen your work, whhen I was referring to example code I meant yours.

Guys, I'm about a month away from prototype and I am sure I will be in touch soon.

Thanks again
Chris

Dean! I just noticed you're an Aussie. Me too, I'm in Sydney now but was born and bred in Melbourne.