XC3S400-4FT256C Xilinx Inc, XC3S400-4FT256C Datasheet - Page 26

• Manufacturer Part Number: XC3S400-4FT256C
• Description: SEMI CONDUCTOR
• Manufacturer: Xilinx Inc

Specifications of XC3S400-4FT256C

• Case: BGA
• Dc: 04+

Spartan-3 FPGA Family: Functional Description
Table 12: Block RAM Port Signals
26
54
Address Bus
Data Input Bus
Parity Data
Input(s)
Description
Notes:
1.
2.
3.
4.
Signal
ADDRA[r
ADDRB[r
w
p
r
The control signals CLK, WE, EN, and SSR on both ports have the option of inverted polarity.
DIA[w
DIB[w
A
A
A
and r
DIPB[3:0]
and p
DIPA[3:0]
and w
SSRA
A
A
SSRB
B
B
CLKA
CLKB
WEA
WEB
–1:0]
–1:0]
–1:0]
–1:0]
B
ENA
ENB
B
B
are integers representing the address bus width at ports A and B, respectively.
are integers that indicate the number of data path lines serving as parity bits.
are integers representing the total data path width (i.e., data bits plus parity bits) at ports A and B, respectively.
ADDRA
Port A
Signal
Name
DIPA
DIA
RAMB16_Sw
(a) Dual-Port
ADDRB
Port B
Signal
Name
DIPB
DIB
A
_Sw
B
Figure 12: Block RAM Primitives
DOPA[p
DOA[w
DOPB[p
DOB[w
Direction
Input
Input
Input
A
B
A
–1:0]
B
–1:0]
–1:0]
–1:0]
www.xilinx.com
The Address Bus selects a memory location for read or write
operations. The width (w) of the port’s associated data path
determines the number of available address lines (r).
Whenever a port is enabled (ENA or ENB = High), address
transitions must meet the data sheet setup and hold times with
respect to the port clock (CLKA or CLKB). This requirement
must be met, even if the RAM read output is of no interest.
Data at the DI input bus is written to the addressed memory
location addressed on an enabled active CLK edge.
It is possible to configure a port’s total data path width (w) to be
1, 2, 4, 9, 18, or 36 bits. This selection applies to both the DI and
DO paths of a given port. Each port is independent. For a port
assigned a width (w), the number of addressable locations is
16,384/(w-p) where "p" is the number of parity bits. Each
memory location has a width of "w" (including parity bits). See
the DIP signal description for more information of parity.
Parity inputs represent additional bits included in the data input
path to support error detection. The number of parity bits "p"
included in the DI (same as for the DO bus) depends on a port’s
total data path width (w). See
ADDR[r–1:0]
DIP[p–1:0]
DI[w–1:0]
SSR
CLK
WE
EN
Function
(b) Single-Port
Table
RAMB16_Sw
13.
DS099-2 (v2.2) May 25, 2007
Product Specification
DOP[p–1:0]
DO[w–1:0]
DS099-2_13_112905
R