Can FPGA read and write SD card in 4 bit SD mode?
The DAT[0:3] lines are bi-directional in this case.
It seems hard to deal with it.
Any ideas or should I purchase some written SD mode driver (where can I find it?)?
I think bidirectional bus operation is a problem because I was thinking I can only assign a line to be either input or output in FPGA's GPIO. If it's bidirectional, I would have difficulty to tell part when it works as an input line and when it works as an output line.
Thanks for sharing the project!
But I haven't had a full account.. Can anyone upload it?
Thanks in advance.
Otherwise I have to wait two days until my account in OpenCores get approved.
you create a signal named test_o_en in your design and assert it whenever you want to send something on your bidirectional 'test' signal. Drive '0' on it when you want 'test' to be in input mode.