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Topic: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!! (Read 18910 times) previous topic - next topic

New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Two new Arduino boards have been released:

- Arduino Uno
- Arduino Mega2560

The most drastic change is that they have replaced the FT232RL with an AT90USB82 (2,-- EUR @ 100qty) for the USB-serial chip!!!

The Arduinos now have their own VID/PID and need no FTDI driver any longer! Like the DP projects that make use of PIC USB MCUs (Flash Destroyer, IR Toy) only an .inf file is needed for the installation.

Maybe we should consider moving away from the FT232R for future projects with MCUs that provide no USB port and look in the direction of PIC18F24J50 or AT90USB82/162 for the USB-serial interface.

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #1
The advantage of the AT90USB for this purpose is that there's an open source USB stack (LUFA). I believe this is an issue with using the USB PICs for open source projects, but I admit I haven't been paying close attention.

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #2
alm is right, LUFA is an open stack for AVR. We're still working on an open PIC stack, but it is very workable at the moment.

Microchip also has a new 8 (or a few more? 28?) pin USB->serial transceiver that's cheaper than the FTDI chip. The main benefit of the FTDI chip is that everyone uses it so it's highly available and the consolidated BOM means they're really cheap for us because Seeed orders a ton at once.
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Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #3
I wanted to add - when I first saw this topic I was really curious how they were doing it. I thought maybe the Arduino + bootloader had gone integrated USB.
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Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #4
The source code for the AT90USB82 on the new Arduinos is freely available and yes, they use the LUFA stack for AT90USBs.
If you are curious, take a look:

http://github.com/arduino/Arduino/tree/ ... firmwares/ --> arduino-usbdfu/

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #5
I've been skimming AVR documentation off and on for months, and it seems like a USB bootloader is available from the factory, and I believe it is DFU compatible.  Looks like they also have Flash protection so that the bootloader shouldn't get erased by accident.  All in all, that's a lot prettier than the effort needed to get the same features on the PIC.  Then again, certain PIC models have hardware features that are impossible to add to the AVR...

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #6
http://electronics.stackexchange.com/questions/4539/what-are-you-going-to-do-with-the-arduino-uno

Quote
Re: Arduino Uno

I'm a huge fan of the USB-AVRs. Last year I built an AT90USB162 board. Since then, I've been working on a single chip Bus Pirate clone on one and using them to build USB connected test jigs for our production line.
...
I had hoped that the Arduino Uno would combine the two chips. But, I'm disappointed. My advice - wait for v1.1 (Uno punto uno?) (see @reemrevnivek below).

Looking at the Uno schematic, they haven't connected up most of the pins from the ATmegaU8 (not even out to pads). So, some the LUFA stuff won't work without big changes (JTAG, AVR programming, SD cards as mass storage, etc)

There are two lines connecting the ATmegaU8 to the ATmega328 - meant for a serial link.

My advice, buy a Teensy. If the Arduino users start coding for ATmegaU8 it'll run better on Teensy's ATmegaU4 and have acres of flash and RAM left. With the DFU/HID bootloader in the ATmega8, things must be very tight indeed.

PS. ATmegaU8 as FTDI replacement for Arduino - see Benito and Uno response.

PPS. Here's the FAQ. The U8 is a cost down.

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #7
Yeah, I don't see the point of paying for two AVR chips just to maintain compatibility with the Arduino.  There's not really anything crucial in that world that can't be done better.  Personally, I'd love to see a single-chip USB-AVR board with lots of I/O breakouts - why not break into the modern world?

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #8
True, there is no need for a dedicated USB controller on the Arduinos.

They could go 32-Bit i.e. AVR32UC3B based board - winavr toolchain to be replaced with the GNU AVR32 toolchain in Arduino IDE ;)

Or, for the "big" ATmegas without USB controller they could use V-USB - works well for a virtual COM port!

... or go AT90USB1287 with LUFA for the USB part ... but some/all (?) of the 5V shields could not be used anymore.

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #9
Why not just keep most things the same, use an 8-bit USB-AVR, and put some 3.3V-to-5V logic level shifter/buffer chips for the shields?  I haven't studied the AVR data sheets side by side, but it doesn't seem that there could be much difference between them.

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #10
I didn't check the data sheet for the AT90USB1286 and AT90USB1287 ... operating voltage range for Vcc is 2.7V ... 5.5V. All shields should still work.
Those chips are hard to source, so.

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #11
What about the AT90USB82 that is specifically used in the Uno?  Same voltages?  Same availability/sourcing?

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #12
The AT90USB82 has only 8k flash ... it's the smallest USB AVR.

AT90USB646/AT90USB1286 (full-speed USB 2.0 device) or AT90USB647/AT90USB1287 (full-speed USB 2.0 device/host OTG) would be options for an Arduino Mega. ATmega32U2 or ATmega32U4 are the 32k flash size "equivalents" to the ATmega328 used on the Arduino/Arduino Uno ... but then the code for the virtual COM port in addition to the bootloader would reduce the memory available for applications considerably.

In the end the Arduino team made the right decision to use two MCUs (one for USB communication and the other one for applications). It keeps the small (Arduino Uno) and the big Arduino (Mega 2560) compatible and gives maximum space for applications on the Uno. Beyond compatibility the AT90USB82 can be reprogrammed and used to flash the ATmegas via the SPI interface (kind of like the bit-bang option the USB Arduinos with FT232RL had) or for other applications. The new Arduinos even cost a little less than their predecessors and I think they are great designs.

If it's all about price then a "light version" could  use an ATmega640, ATmega1280 or ATmega2560 with a "soft" USB virtual COM port.

 

Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #13
I think part of the issue has to be ease of use. USB isn't simple. Beginners want (need) to poll and use blocking loops, and USB drivers usually need more attention than that. I would have done the same thing.
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Re: New Arduinos - Arduino Uno and Arduino Mega 2560 - no more FT232R!!!!!

Reply #14
I think after all these years of staying away from Arduino, it is time for me to get at least the Arduino Uno board. For quick prototyping stuff. And also an mBed maybe and... (the list goes on)