XCS05XL Xilinx, XCS05XL Datasheet - Page 4

• Manufacturer Part Number: XCS05XL
• Description: Spartan and Spartan-XL Families Field Programmable Gate Arrays
• Manufacturer: Xilinx

Spartan and Spartan-XL Families Field Programmable Gate Arrays
A CLB can implement any of the following functions:
•
•
•
•
Implementing wide functions in a single block reduces both
the number of blocks required and the delay in the signal
path, achieving both increased capacity and speed.
The versatility of the CLB function generators significantly
improves system speed. In addition, the design-software
tools can deal with each function generator independently.
This flexibility improves cell usage.
4
Any function of up to four variables, plus any second
function of up to four unrelated variables, plus any third
function of up to three unrelated variables
Note: When three separate functions are generated, one of
the function outputs must be captured in a flip-flop internal to
the CLB. Only two unregistered function generator outputs
are available from the CLB.
Any single function of five variables
Any function of four variables together with some
functions of six variables
Some functions of up to nine variables.
DIN
G4
G3
G2
G1
SR
EC
H1
F4
F3
F2
F1
K
Figure 2: Spartan/XL Simplified CLB Logic Diagram (some features not shown)
G4
G3
G2
G1
F4
F3
F2
F1
G-LUT
F-LUT
Function
Function
G1-G4
F1-F4
Logic
Logic
of
of
G
G
Multiplexer Controlled
by Configuration Program
A
G
H1
F
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H-LUT
Function
F-G-H1
Logic
of
B
H
Flip-Flops
Each CLB contains two flip-flops that can be used to regis-
ter (store) the function generator outputs. The flip-flops and
function generators can also be used independently (see
Figure
to either of the two flip-flops. H1 can also drive either
flip-flop via the H-LUT with a slight additional delay.
The two flip-flops have common clock (CK), clock enable
(EC) and set/reset (SR) inputs. Internally both flip-flops are
also controlled by a global initialization signal (GSR) which
is described in detail in
page
Latches (Spartan-XL only)
The Spartan-XL CLB storage elements can also be config-
ured as latches. The two latches have common clock (K)
and clock enable (EC) inputs. Functionality of the storage
element is described in
20.
2). The CLB input DIN can be used as a direct input
Table
Global Signals: GSR and GTS,
D
CK
EC
D
CK
EC
DS060 (v1.6) September 19, 2001
SR
SR
2.
DS060_02_0506 01
Q
Q
Product Specification
YQ
Y
XQ
X
R