I have an ATTINY2313-20SI running at 12MHz, and configured to run the IGOR firmware USB stack. I have a maxim bi-directional level translator on board so that I can run the processor at 12MHz and still be in spec (as someone posted on th avr-gcc-list - the device is only rated to 10MHz at VCC < 4.5V)
But the bi-directional level translator seems to have grief because of the 1k5 pullup resistor on the Data- line.
I have therefore modified the circuit for now, and run everything at 5V. Evertyhing works ok like this for development, but I need to get the level translation right in order to complete the board.
Has anyone done a level translation that works ok on the USB data lines? Any help is much appreciated! 8)