Objective Development Forums

Seems to be true: the Tiny2313 may not be able to reach 12.8 MHz...

This is not so much of an issue because it's hard to implement something useful in only ~ 300 bytes of code. The 12.8 MHz driver is much bigger than the other modules.

When the basis is set to 0, strtol() determines the basis from the number's prefix. If it's 0..., then the number is interpreted as octal, if it's 0x..., then as hex and if it's any other digit then it must be decimal.

Sorry, I don't have the time to go through your code. But I can confirm that sending a 18 byte report as 8 + 8 + 2 should work as long as you make sure that the buffer is available when you call usbSetInterrupt().

Sorry, I don't have the time to go through your code. But I can confirm that sending a 18 byte report as 8 + 8 + 2 should work as long as you make sure that the buffer is available when you call usbSetInterrupt().

The final dot is not part of the URL, the URL is

http://www.obdev.at/products/avrusb/links.html

A software host for low speed devices is possible and there are implementations available, see http://instruct1.cit.cornell.edu/course ... index.html

You CAN use a UART interrupt together with USB. But you must make sure that the first thing your interrupt routine does is to set the global Interrupt Enable flag. In GCC you do this by declaring the interrupt with "__attribute__ ((interrupt))".

When you send reports of more than 8 bytes, concatenate several calls to usbSetInterrupt() and make sure the buffer is empty with usbInterruptIsReady() before you call usbSetInterrupt(). The last chunk should be less than 8 bytes to indicate the end of transfer.

I don't think using the comparator brings an advantage. Signals are usually good enough for direct detection by input ports.

Checking CRC during reception is probably possible at 18 MHz. You need a 256 byte CRC table for that.

Regarding bzero: Seems to be a problem of header versions. My MinGW installation has it...

Regarding -lusb: You need to install libusb-win32. This is a separate install not included with MinGW. The example demonstrates how to use direct (libusb based) access to HID devices.

Did you check the voltage level on D-? It should be between 3 and 3.6 V when no data is transferred. You need low power zener diodes on D+ and D- unless you use a 3.3 V voltage regulator for the AVR's supply.

PORTC is the output port (more or less write-only) while PINC is the input port (read-only).

If you use a voltage divider, you limit the pull-up voltage only, not the signal levels generated by the processor. For reliable communication, the signal levels need to be near the levels defined in the USB spec.

Regarding the pull-up: I use 1.5 kOhm usually, but it all depends on the zener diodes. The voltage should be between 3 and 3.3 V in idle mode.

Regarding the endpoint: Endpoint 0 is always there and is a control endpoint. You don't need to declare it.

Yes, looks OK. But please also check the idle voltage on D-. It should be above ~ 3 V.