EP2AGX95EF29C6N Datasheet, PDF (39/380 Pages) Altera Corporation – Device Interfaces and Integration

Chapter 2: Logic Array Blocks and Adaptive Logic Modules in Arria II Devices
2–9
Adaptive Logic Modules
For the packing of two 5-input functions into one ALM, the functions must have at
least two common inputs. The common inputs are dataa and datab. The combination
of a 4-input function with a 5-input function requires one common input (either dataa
or datab).
In the case of implementing two 6-input functions in one ALM, four inputs must be
shared and the combinational function must be the same. In a sparsely used device,
functions that could be placed in one ALM may be implemented in separate ALMs by
the Quartus II software to achieve the best possible performance. As a device begins
to fill up, the Quartus II software automatically utilizes the full potential of the
Arria II ALM. The Quartus II Compiler automatically searches for functions using
common inputs or completely independent functions to be placed in one ALM to
make efficient use of device resources. In addition, you can manually control resource
usage by setting location assignments.
Any 6-input function can be implemented using inputs dataa, datab, datac, datad,
and either datae0 and dataf0 or datae1 and dataf1. If datae0 and dataf0 are utilized,
the output is driven to register0, and/or register0 is bypassed and the data drives
out to the interconnect using the top set of output drivers (refer to Figure 2–8). If
datae1 and dataf1 are used, the output either drives to register1 or bypasses
register1 and drives to the interconnect using the bottom set of output drivers. The
Quartus II Compiler automatically selects the inputs to the LUT. ALMs in normal
mode support register packing.
Figure 2–8. Input Function in Normal Mode (Note 1)
dataf0
datae0
dataa
datab
datac
datad
datae1
dataf1
(2)
6-Input
LUT
labclk
DQ
reg0
DQ
reg1
To general or
local routing
To general or
local routing
To general or
local routing
Notes to Figure 2–8:
(1) If datae1 and dataf1 are used as inputs to a 6-input function, datae0 and dataf0 are available for register packing.
(2) The dataf1 input is available for register packing only if the 6-input function is unregistered.
December 2010 Altera Corporation
Arria II Device Handbook Volume 1: Device Interfaces and Integration