DS561 Datasheet, PDF (25/29 Pages) Xilinx, Inc – PLBV46 SLAVE SINGLE

PLBV46 SLAVE SINGLE (v1.01a)
architecture USER_ARCH of user_top_level;
-- Extract the number of CEs assigned to the second address pair
Constant NUM_USER_01_CE : integer := C_ARD_NUM_CE_ARRAY(1);
-- Determine the CE indexes to use for the the second Register CE
Constant USER_01_START_CE_INDEX : integer := calc_start _ce_index(C_ARD_NUM_CE_ARRAY, 1);
Constant USER_01_END_CE_INDEX : integer := USER_01_START_CE_INDEX + NUM_USER_01_CE - 1;
-- Declare signals
signal user_01_cs
signal user_01_rdce
signal user_01_wrce
begin (architecture )
: std_logic;
: std_logic_vector(0 to NUM_USER_01_CE -1);
: std_logic_vector(0 to NUM_USER_01_CE -1);
-- Now rip the buses and connect
user_01_cs
<= Bus2IP_CS(1);
user_01_rdce
<= Bus2IP_RdCE(USER_01_START_CE_INDEX to USER_01_END_CE_INDEX);
user_01_wrce
<= Bus2IP_WrCE(USER_01_START_CE_INDEX to USER_01_END_CE_INDEX);
Figure 13: Bus Ripping Example
Point-To-Point Configuration
A Point-To-Point configuration is defined as 1 Master talking to 1 Slave over the PLB Bus. If the PLB
topology is configured such that it is a Point-To-Point configuration then some of the FPGA resource
utilization can be reduced as well as some of the latency through the slave (See Figure 13 through
Figure 14). To accomplish this the user must set C_SPLB_P2P = 1.
Single Address Pair in C_ARD_ADDR_RANGE_ARRAY
For situations where the User does not require additional slave services then 1 address pair should be
defined in C_ARD_ADDR_RANGE_ARRAY. The address pair should span the entire address range of
the system. For example, set the base address to X"0000_0000_0000_0000" and set the high address to
X"FFFF_FFFF_FFFF_FFFF".
Multiple Address Pair in C_ARD_ADDR_RANGE_ARRAY
For situations where other slave services are required, such as interrupt control and/or soft reset
services, then the user will need to define multiple address pairs in C_ARD_ADDR_RANGE_ARRAY.
If the user defines multiple address pairs in C_ARD_ADDR_RANGE_ARRAY then from a system
perspective the PLB Bus starts looking like a shared bus, i.e. one having multiple Slaves. For this
configuration the bus no longer represents a point to point configuration. In other words the address
decode logic must be instantiated in the Slave Attachment to decode the multiple address ranges.
When multiple address pairs are defined in C_ARD_ADDR_RANGE_ARRAY and C_SPLB_P2P = 1
DS561 June 22, 2010
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