A while back, I proudly wrote about my newest foray into the realm of AT90USB.  The past few days, I've been working on some code for the board.  Not much, just some simple changes to the stock Atmel CDC demo.  At first I just put the Atmel demo on the chip and plugged it into my computer.  Perfect.  A USB serial port.  Last night, I plugged it into a Linux system.  It pretty much worked.  Tonight, I decided to try getting my two computers to actually talk to the device.

Not so much luck.  I stripped out everything except a blurb which is supposed to print a string when you press a button.  It seemed to work under Windows, but behaved erratically under Linux.  The I realized, it was behaving badly under Windows as well.

The string of text just kept displaying, whether I touched the button or not.  Sometimes if I tried to transmit text, communications would come to a screeching halt...

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  Per usual, I have an Evil Genius (TM) scheme in the works.  The scheme involves using Linux to control a robot.  Of course, I need a way for the CPU to talk to the peripherals.  USB is a great choice, especially since AT90USB is cheap and easy to use.

The chip shown to the left costs only about as much as its FTDI counterpart, except that it can be completely programmed in C.  This is the latest incarnation of my development board.  One of the buttons is reset, and the other one triggers the bootloader.  For the sake of simplicity I will probably emulate a USB serial port and then use the serial port to talk to the board from Linux.  A generic HID class would also work, but that might be a bit more work than I want to commit to right...

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Last summer Atmel released exciting news.  They had gone into production with their new 32 bit series of processor, the AT32 (alternately called AVR 32).  Unfortunately the debugging tools are a bit too expensive for me, and creating a circuit containing the processor, RAM, and flash memory would take much expertise that I have not got.  Further, the chance of getting the whole thing running without the complete debugging environment is extraordinarily slim. 

Lucky for me, Atmel released a microcontroller version of the chip.  This version is much more accessible to fiddlers like myself, although it only started becoming available for purchase in the last couple of months.  In the meantime, I slathered at the mere thought of getting my grubby mitts on one of these chips.  Well, I finally did.  The only one available for order at the time was a 144 pin TQFP.  Since I've never worked with this chip, my first task was to create an adapter board that I could use to get the chip running in a test environment.

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