ep1s25 Altera Corporation, ep1s25 Datasheet - Page 27

• Manufacturer Part Number: ep1s25
• Description: Stratix Device Family Data Sheet
• Manufacturer: Altera Corporation

Figure 2–8. Carry Select Chain
Altera Corporation
July 2005
LAB Carry-In
A1
B1
A2
B2
A3
B3
A4
B4
A5
B5
A6
B6
A7
B7
A8
B8
A9
B9
A10
B10
LAB Carry-Out
0
0
LE1
LE2
LE3
LE4
LE5
LE6
LE7
LE8
LE9
LE10
1
1
Sum1
Sum2
Sum3
Sum4
Sum5
Sum6
Sum7
Sum8
Sum9
Sum10
Clear & Preset Logic Control
LAB-wide signals control the logic for the register’s clear and preset
signals. The LE directly supports an asynchronous clear and preset
function. The register preset is achieved through the asynchronous load
of a logic high. The direct asynchronous preset does not require a NOT-
gate push-back technique. Stratix devices support simultaneous preset/
LAB Carry-In
Carry-In0
Carry-In1
data1
data2
Stratix Device Handbook, Volume 1
Carry-Out0
LUT
LUT
LUT
LUT
Carry-Out1
Stratix Architecture
Sum
2–13