On 10/25/07, Robin Abbott wrote: > I converted Microchip's CDC code into a drag and drop component for our own > compiler (WIZ-C), which wasn't too bad a task - except that the silicon has > a bug which meant that spurious bytes are inserted in transmitted packets > unless the timing relationships are exactly correct. Which silicon bug are you referring to? I've collected a list of potential firmware frameworks bugs in the Microchip forum thread. http://forum.microchip.com/tm.aspx?m=275422 The new V1.2 stack solved some problems but not all. The suspend handling code (sleeping) is still causing problems. > I am assuming that you > are looking at the 18F devices, the 16F devices are limited. > I believe a 20 pin device is on the way. That would be nice. > > I would suggest you look hard at HID or CDC. Understanding the Microchip > libraries is not too difficult to get your head around once you have looked > at them together with the USB standards (which are quite readable and > available from the USB forum). HID or CDC USB can use standard Windows > drivers with a simple INI file and then most compilers/development systems > in Windows can be used relatively easily. Should be INF file. HID normally uses the built-in INF file. CDC-ACM will require an INF file. However the built-on usbser.sys is not really that stable. Custom driver from FTDI and Silicon Labs for their USB Serail device are much better. > A full custom USB implementation requires you to build a Windows device > driver - which personally I find a magnitude harder than using CDC or HID ! > That said Microchip do have an example in their USB libraries. The driver is not easy but Microchip has already provided the driver (but not open source and not well documented). You can also use Windows DDK drivers like bulkusb. > FTDI is quite an expensive solution which requires you to have many > additional components in your implementation over and above the > base PIC. For USB to serial conversion, I think FTDI is much better than CDC-ACM with 18F USB. But an 18F USB PICs can do a lot more. Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist