Expansion Bus I/O Port Operation
8-13
Expansion Bus
Notes:
1) XRDY is active (low) during host-port accesses.
2) XBE[3:0]/XA[5:2] operate as XBE[3:0] during host-port accesses.
8.4.2
Synch FIFO Modes
The synchronous FIFO mode of the expansion bus offers a glueless and/or low
glue interface to standard synchronous FIFOs.
The expansion bus can interface up to four write FIFOs without using glue logic
(one per XCE space) or three write FIFOs and a single read FIFO (in XCE3
only). However, with a minimal amount of glue, up to 16 read and write FIFOs
can be used per XCE space.
The XOE, XRE, XWE, and XCEn signals are not tri-stated while the DSP re-
leases control of the expansion bus.