Objective Development Forums

If usbInterruptIsReady() is never true, then the host does not poll the interrupt endpoint. There are two possilbe causes for this: (1) The endpoint is not declared correctly in the configuration descriptor, or (2) the device did not respond when the host polled the interrupt endpoint and the host t...

The default control endpoint is endpoint 0. It need not be listed in the configuration descriptor's list of endpoints because it's always there and MUST be a control endpoint.

I don't see a reason why it should not work, but I have never tried it myself.

We may add a 20 MHz module, but I don't see a demand for 18 MHz.

Sorry, I don't have the time to go through your code and descriptors, but some comments: It's OK that D+ is at 0 V and D- at 3.3 V. This is the idle status when no data is transferred. Since data is transferred in bursts, you see the bus idle most of the time. If the device is recognized by Windows,...

Please see my reply in the other thread: http://forums.obdev.at/viewtopic.php?t=1002 . When you move the descriptor to your own code, you can remove all the #ifs and many definitions because the values are known. That makes it MUCH easier to see the structure and find potential bugs.

If you want more than the most basic configuration descriptor, please put the entire descriptor into your own C module and add #define USB_CFG_DESCR_PROPS_CONFIGURATION USB_PROP_LENGTH(xxx) to your usbconfig.h where xxx stands for the length of the descriptor in bytes. Alternatively you can add #def...

To everybody who uses the AVR-Doper firmware: There's a serious bug in the ISP MULTI command which is used (e.g.) by avrdude to read fuse values. The effect of the bug is to send uninitialized data to the device on the ISP interface. The commands may have undesired effects such as changing fuse valu...

It's a matter of personal preference. Newer versions are not always better. I, personally, prefer gcc 3 because of the somewhat smaller code and because I'm used to its behavior (which warnings are on by default and so on). On the other hand, new features are only added to gcc 4. If you want any of ...

Here's an example: char buffer[44]; /* fill buffer with data here... */ nBytes = usb_control_msg(handle, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_OUT, MY_REQUEST_ID, 0, 0, buffer, 44, 5000); if(nBytes < 0) fprintf(stderr, "USB error: %s\n", usb_strerror(...

I don't know how you want to control the communication direction of your RS485 interface. If the device should look like a serial interface, I'd recommend that you implement a CDC class device. See m for an example. This class of device does not need a Windows driver, only a .inf file which tells it...

usbFunctionWrite() should be defined in your own code. It is called by the driver when control data is received. See the documentation in usbdrv.h for details. usbCrc16() is defined in the assembler module. If the linker does not find it, you don't link usbdrvasm.S. Add this file to your project or ...

A low speed USB device sends with a bit clock of 1.5 MHz. The driver is easier to implement if the CPU clock is a multiple of that. For crystal based designs, I would recommend 12 MHz as this is the oldest and therefore best tested implementation. But you can also use 15 or 16 MHz crystals, as long ...

Before you connect the programmer, please run the following command in a Terminal window:

tail -f /var/log/system.log

Then connect the device and watch the messages in the Terminal window. This may provide more information.

The newer versions of the driver don't really care whether you connect D+ or D- to INT0. For counting frames, however, you MUST connect D- to INT0 because only D- carries the frame marker.