Objective Development Forums

Yes. Zener diodes have a high capacity which distorts the signals. Low power diodes have less capacity. And the nominal voltage is measured at lower currents for low power types. You may have to choose a higher voltage for higher power types. For an experimental circuit, you may try several Si-diode...

Just for the reference:
You can use crystal clocks of 12, 15, 16, 16.5 or 20 MHz. Lower rates are not supported. An RC clock of 16.5 MHz is also supported, but this clock is only available on some AVRs such as the ATTiny25, 45, 85 and ATTiny26.

If no data must be processed (99% of the calls), it does two global variable loads, two comparisons and returns. You must call it at least every 50 ms, see usbdrv.h for more info about the API.

See "embedded USB hosts" at http://www.obdev.at/products/avrusb/links.html. The first link is a firmware implementation.

Please start with a less complex example, something which does not require the boot section and switching the interrupt vectors. When that works, you can at least be sure that the hardware infrastructure is OK.

The most likely cause for this is a voltage level problem on D+ or D-. Please check the idle voltage on D- and ensure it's above 3 V and below 3.6 V.

Other things to try: Different host, insert USB 2.0 hub, swap USB cables etc. If one of these helps, a voltage level problem is very likely.

usbPoll() returns within a few microseconds, unless a message was received. If a message was received, it calls one of your functions (e.g. usbFunctionSetup()) and returns then. usbPoll() NEVER blocks by itself. The code example you gave won't work because you don't call usbPoll() often enough. You ...

Did you choose the same options for the boot loader (same emulation level) as when you do a "make allhexfiles"? Other than that, you might use a different version of avr-libc (although I doubt that this make such a great difference).

I compiled this with gcc 3.4.6. If you use WinAVR, you must use a rather old version (before the switch to gcc 4).

For the Pin Change thing, see the end of this thread: m This was on the tiny45, but it's still an example for using the pin change interrupt. A different issue: The osccal routine is too big for a 2 k boot loader. Your code size is ~ 2.5 k, too much for the boot section. You'll probably find a diffe...

I'm not sure I understand what you are asking... Looking at the code: You still have those defines commented out. But I see that you have already found the appropriate values for the defines. I have not checked them, but you obviously understood the concept. Regarding interrupt edge sensitivity: The...

Please download the latest driver and see the hid-data example in the examples directory. Or read the documentation for usbFunctionWrite() in usbdrv.h.

I never tried gcc with avrstudio, so I can't comment on that. If you use WinAVR, you can use our standard Makefiles. Adding osccal.c may become tight due to the 2kB restriction for boot loaders. To use the Pin Change Interrupt, you need to change the last section of usbconfig.h: /* -----------------...

It seems that Windows Vista forbids low speed devices with bulk endpoints. Osamu has a workaround for this, see www.obdev.at/goto.php?t=lowbulk

The example above is for sending data from the host to the AVR, as you requested. On the AVR side, you need to implement usbFunctionWrite(). See the hid-data example which ships with the driver for details.