DS581 Datasheet, PDF (25/50 Pages) Xilinx, Inc – PLB interface with byte enable support

XPS External Peripheral Controller (EPC) v1.02a
output at CLKFX pin of DCM0. Another DCM (DCM1) is used to synchronize the device peripheral
clock to the PRH_Clk signal of XPS_EPC.
Figure Top x-ref 5
FPGA
DCM0
CLKIN CLKFX
PRH_Clk
CLKFB CLK0
DCM1
PRH_Clk_FB ^CLKIN
SPLB_Clk
XPS EPC
SPLB_Clk
PRH_Clk
External
Device
CLKFB CLK0
CLK
DS581_05_080309
Figure 5: External Peripherals clocked by FPGA output with feedback
Example Peripheral Connections
Example: SMSC LAN91C111 10/100 non-PCI Ethernet Single Chip MAC + PHY
An example peripheral device supported by the XPS EPC IP Core is the SMSC 10/100 non-PCI
Ethernet Single Chip MAC + PHY LAN91C111. The XPS EPC IP Core allows PLB masters to access the
device both in synchronous and asynchronous mode. The device connections for synchronous and
asynchronous mode of operations are outlined in the Asynchronous Mode and Synchronous Mode
sections.
Asynchronous Mode
Figure 6 illustrates the SMSC LAN91C111 connections to the XPS EPC IP Core in asynchronous mode
with non-multiplexed address and data buses. In asynchronous mode, the input clock source
(PRH_Clk) to the external device must be tied to Vcc. When the SMSC LAN91C111 is accessed through
the asynchronous mode, the rising edge of PRH_Rd_n and PRH_Wr_n signals are used to control the
read and the write operations respectively. As the device uses Asynchronous Ready (ARDY) signal to
indicate its readiness in asynchronous mode. This signal is connected to the PRH_Rdy input of the XPS
EPC IP Core. Since the address and the data buses are not multiplexed, PRH_ADS will be driven low by
the XPS EPC IP Core. The timing parameters should be set according to the SMSC LAN 91c111 Async
mode specifications.
The following parameter settings apply for the connections shown in Figure 6.
• C_PRH_CLK_SUPPORT = 0
• C_PRH0_AWIDTH = 16
• C_PRH0_DWIDTH = 32
• C_PRH0_SYNC = 0
• C_PRH0_DWIDTH_MATCH = 0
• C_PRH0_BUS_MULTIPLEX = 0
DS581 September 16, 2009
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Product Specification