Objective Development Forums

Thanks for this valuable info! I'll fix this for the next release.

These two defines should be all you need to change. And then you need to do a "make clean" because there are no dependencies on usbconfig.h and Makefile. AVRs can usually be overclocked quite a bit, so I doubt that it's a hardware problem. I've tested the 20 MHz module myself and it worked...

As far as I know, USB wakeup is specified as an SE0 condition or USB reset (D+ and D- both 0, for SE0 only two bits long, for reset several 100 ms). Can't remember which of the two it was, but I guess it was the short pulse.

Don't know anything about LIRC, but it is definitely possible to have two apps communicating with the device. Make sure that all communication is done through control transfers on endpoint 0, you don't need to set an interface or configuration for this. If you need to set an interface or configurati...

Make sure that you do a "make clean" after changing USB_CFG_IMPLEMENT_FN_WRITE in usbconfig.h. The makefile does not contain dependencies on this file, as far as I remember. Or delete all object files manually to ensure that everything is re-compiled.

The PC won't tell you directly when it turns on or of. You can check for SOF pulses on D-. They occur every 1 ms if the PC is on. It helps to have D- on an interrupt or even use D- for the USB interrupt in order to detect these pulses.

The function call in the comment is somewhat outdated now...

You would call usbCrc16(data, len) and compare the result to data[len] and data[len + 1].

If you use the 12.8 MHz module (the 12 MHz module won't work because it requires an EXACT clock rate), you also need to add the oscillator calibration. There are two types, see the libs-device directory in the driver distribution. The calibration will tune the oscillator from 8 MHz to 12.8 MHz.

The examples are primarily for the AVR side. On Windows, you need libusb-win32 for the low level device driver.

You can use the 12.8 MHz version on the Mega8 with the built-in RC oscillator.

This can't work on Vista because it uses bulk endpoints. You need a patch in a similar way as for AVR-CDC.

BTW: Why don't you host the project on our wiki at http://vusb.wikidot.com/hosted-projects ?

The limitations are for the license only, not the USB IDs. You can do with the USB IDs whatever you want.

It's OK to use the shared IDs for commercial products. In any case, you can't be USB compliant with our USB IDs because usb.org requires that you own the vendor-ID to be compliant.

And did you configure V-USB with USB_CFG_IMPLEMENT_FN_WRITE defined to 1 in usbconfig.h?

The low level USB packets are always maximum 8 bytes for low speed devices. Larger blocks are transferred in chunks of 8 bytes. V-USB handles this more or less transparently, it calls usbFunctionRead() and usbFunctionWrite() for blocks of 8 bytes.

You must not perform any long lasting actions in these functions. And you must not call usbPoll() from within usbFunction*().

If you have to do long lasting processing, collect the data in a buffer and perform the processing in the main loop. You can easily call usbPoll() from there.