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Unread 24-02-2009, 20:04
Shinigami2057 Shinigami2057 is offline
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Re: Using a GPIO pin for both input and output.

Quote:
Originally Posted by EricVanWyk View Post
Take a look at the I2C interface schematic for another implementation.



Can you explain what you mean by this? I am unsure as to what feature you want to add. The direction change timing is a function of the module, not of the FPGA image. The provided image doesn't get in the way unless you ask it to.
Thanks for the clarification; I was under the impression the FPGA was handling the digital I/O as well. If the digital I/O is left untouched, what is the expected delay of changing the direction? Is it enough to warrant using a custom circuit with two pins?

One more quick question: is there any more concrete documentation on what exactly the FPGA does and does not do, and perhaps documentation on how to interface directly with the cRIO functionality? Looking at the WPILib implementation, there's a lot of headers without corresponding source files in the DIO/ChipObject interfaces. If I'd like to work on my own interface/API, would it be possible to get more specific docs or would I have to use WPILib as a reference to how to use the hardware?
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