Cypress Semiconductor FX2LP Informacje Techniczne Strona 159

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Chapter 9. Slave FIFOs Page 9-3
9.2.1 Slave FIFO Pins
The FX2 comes out of reset with its I/O pins configured in “Ports” mode, not “Slave FIFO” mode. To
configure the pins for Slave FIFO mode, the IFCFG1:0 bits in the IFCONFIG register must be set
to 11 (see Table 13-10, “IFCFG Selection of Port I/O Pin Functions" for details). When
IFCFG1:0 = 11, the Slave FIFO interface pins are presented to the external master, as shown in
Figure 9-2.
Figure 9-2. FX2 Slave Mode Full-Featured Interface Pins
External logic accesses the FIFOs through an 8- or 16-bit-wide data bus, FD. The data bus is bidi-
rectional, with its output drivers controlled by the SLOE pin.
The FIFOADR[1:0] pins select which of the four FIFOs is connected to the FD bus.
In asynchronous mode (IFCONFIG.3 = 1), SLRD and SLWR are read and write strobes; in syn-
chronous mode (IFCONFIG.3 = 0), SLRD and SLWR are enables for the IFCLK clock pin.
Figure 9-3. Asynchronous vs. Synchronous Timing Models
FX2
Slave
Mode
EXT.
Master
FLAGA
FLAGB
FLAGC
IFCLK
FLAGD / SLCS#
SLOE
SLRD
SLRWR
PKTEND
FD[15:0]
FIFOADR[1:0]
Asynchronous
SLRD
SLWR
Synchronous
SLRD
SLWR
IFCLK
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