C1
C2
C3
C4
H1
DIN
S/R
EC
G4
G3
G2
G1
S/R
CONTROL
DIN
F'
G'
LOGIC
FUNCTION
OF
SD
D
YQ
Q
G'
H'
G1-G4
LOGIC
FUNCTION
OF
F', G',
AND
H1
EC
RD
G'
H'
H'
1
Y
F4
F3
F2
F1
S/R
CONTROL
DIN
F'
G'
H'
LOGIC
FUNCTION
OF
SD
D
XQ
Q
F'
F1-F4
EC
RD
K
(CLOCK)
1
H'
F'
X
MULTIPLEXER CONTROLLED
BY CONFIGURATION PROGRAM
X1519
Figure 13. Simplified Block Diagram of XC4000 Configurable Logic Block
COUT
C1
C2
C3
C4
EC
G4
G3
A1
B1
Logic
Function
of G1 - G4
WE(S/R)
D1(H1)
D0(DIN)
G'
SUM 1
G2
G1
WE
DATA
IN
M
G4
G3
G2
G1
Write G'
G'
Function
Generator
M
Carry
Logic
Write F'
CIN 1
CIN 2
M
16 x 2
Carry
Logic
M
Logic
Function
of F1 - F4
F4
F3
WE
DATA
IN
F4
F3
F2
F1
SUM 0
X5373
F'
F'
B0
A0
F2
F1
M
Configuration Memory Bit
Function
Generator
X6074
Figure 15. CLB Function Generators Can Be Used as
Read/Write Memory Cells
Figure 14. Fast Carry Logic in Each CLB
2-21
XILINX [ XILINX, INC ]
