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I had wrote on this subject last year and put the project down until now. I am having a problem when an external device sets its address lines to outputs while connected to the EZ-USB AN2125 chip at Port D. I an2125 goes into an unknown state. I am using the fast read and fast write on the an2125 and the fast write works just fine. When I attempt to do a fast read the the external device swithches to an output is when the an2125 loses control. Any help would be appreciated.
We are using two micros that are directly connected between their data busses. We are not using a FIFO or buffer at this time. You are right that we can single step a fast write and not a fast read but we are also not able to stop anywhere within the program when the other micro changes from input to outputs on its data bus.
Sure looks like you have bus contention. Each micro thinks it is a bus master. I can not think of a way to do multiple fast transfers without a fifo between them.
I guess I don't understand your comment. The micros never try to send at the same time. Does the data bus on the an2125 always act like an output? The an2125 code works as a stand alone and not on the development board.
Can you send me information on how to set up the options on Target of the monitor for debugging purposes? Thank you for your help!
All I know is the data bus is not shared with I/O pins. The 2125 manual state that the 2125 is the SOLE master of the memory expansion bus. I would talk to Cypress to see if what you are doing is OK.