External Logic Read of the CY7C68013

Question: When using the C7C68013, is there a limit on the number of words/bytes the external logic can read from the FIFO at one time? For instance, when the empty flag is not asserted and the external logic has read 512 bytes from a quad buffered FIFO, does the external device need to stop and check the empty flag before beginning to start reading again?



In both synchronous and asynchronous modes, the external device can read data continuously until the empty flag is asserted. The empty flag will be asserted when there are no more packets (including short packets, a packet with less than 512 bytes) to be read from the FIFO. The external logic should monitor the state of the flag continuosly before reading from the FIFO unless the interface is designed in such a way that the external device has a previous knowledge of the availability of a specifc number of data bytes after initiating the read from the FIFO.

Related Documents:
"EZ-USB FX2 Datasheet"