ep1sgx25d Altera Corporation, ep1sgx25d Datasheet - Page 76

• Manufacturer Part Number: ep1sgx25d
• Description: Stratix Gx Device Family Data Sheet
• Manufacturer: Altera Corporation

Logic Elements
Figure 4–7. Carry Select Chain
4–10
Stratix GX Device Handbook, Volume 1
LAB Carry-In
A1
B1
A2
B2
A3
B3
A4
B4
A5
A6
B6
A7
B7
A8
B8
A9
B9
A10
B10
B5
LAB Carry-Out
0
0
LE1
LE2
LE3
LE4
LE5
LE6
LE7
LE8
LE9
LE10
1
1
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 GX devices support simultaneous
preset/ asynchronous load, and clear signals. An asynchronous clear
signal takes precedence if both signals are asserted simultaneously. Each
LAB supports up to two clears and one preset signal.
In addition to the clear and preset ports, Stratix GX devices provide a
chip-wide reset pin (DEV_CLRn) that resets all registers in the device. An
option set before compilation in the Quartus II software controls this pin.
This chip-wide reset overrides all other control signals.
Sum1
Sum2
Sum3
Sum4
Sum5
Sum6
Sum7
Sum8
Sum9
Sum10
LAB Carry-In
Carry-In0
Carry-In1
data1
data2
Carry-Out0
LUT
LUT
LUT
LUT
Carry-Out1
Sum
Altera Corporation
February 2005