Document No.: FT_000138
VINCULUM-II EMBEDDED DUAL USB HOST CONTROLLER IC Datasheet
Version -
1.2
Clearance No.: FTDI#
143
6.6.2 Read / Write Transaction Asynchronous FIFO Mode
When in Asynchronous FIFO interface mode, the timing of read and write operations on the FIFO
interface are shown in
and
In asynchronous mode an external device can control data transfer driving FIFO_WR# and FIFO_RD#
inputs. In contrast to synchronous mode, in asynchronous mode the 245 FIFO module generates the
output enable EN# signal. EN# signal is effectively the read signal RD#.
Current byte is available to be read when FIFO_RD# goes low. When FIFO_RD# goes high, FIFO_RXF#
output will also go high. It will only become low again when there is another byte to read.
When FIFO_WR# goes low FIFO_TXE# flag will always go high. FIFO_TXE# goes low again only when
there is still space for data to be written in to the module.
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