Suggestion for a project.

Scout · Post by **Scout** » Sun Dec 17, 2006 1:42 am

I've looked at the current and ongoing projects, but I see one need that is sadly missing. A project which will allow the occasional project buiilder to readily interface any AVR project to USB without a lot of added programs to learn, languages to understand, etc. What I would like to see is a simple 1 chip solution, which would act as a standalone interface between another AVR project and the USB port. It would need least one pair of Tx/Rx serial ports with easily adjustable port settings, maybe some pins for optional handshake and some means to select a choice of common HID descriptors. Keyboard, mouse, serial port, mass storage, etc. I hope someone can accept doing a project like this for those of us who need a dirt simple solution for interfacing their project to USB.

Sarge · Post by **Sarge** » Mon Dec 18, 2006 1:40 am

There're a lot of special USB to something converters available:
1. PL2303 from Prolific is USB to RS232 converter (they also provide USB to parallel port converter)
2. FT232 (USB to RS232), FT2232 (two USB to RS232), FT245 from FTDICHIP
3. AT91SAM7S family = ARM7 core + bult-in USB slave at low cost

Post by **christian** » Mon Dec 18, 2006 12:07 pm

As Sarge pointed out, one of the FT232 chips is probably the best solution for this. However, if you want a solution with DIL chips (not SMD) and still small, you may want to look at Osamu Tamura's avrcdc: http://www.recursion.jp/avrcdc/.

Implementing CDC based on AVR-USB is a bit demanding and I admit that a HID to serial converter might be handy for some projects.

os · Post by os » Mon Dec 25, 2006 12:56 am

christian wrote:HID to serial converter might be handy for some projects.

I am not sure if it is possible to implement this in generic way. Porting Atmel AES bootloader to HID, I realized that I have to send exact number of bytes according to HID Report descriptor. So it was required to use a couple of reports which have different number of bytes in them and use bigger report than necessary in some cases.

Maybe other ways are possible but I am not sure if are there any...

Post by **christian** » Mon Dec 25, 2006 5:51 pm

I think this is the best way to implement data streams on top of HID. I've done this in AVR-Doper. The first byte is the number of bytes available and the rest of the report is the payload.