EP2AGX45DF29I5 Altera, EP2AGX45DF29I5 Datasheet - Page 100

• Manufacturer Part Number: EP2AGX45DF29I5
• Description: IC ARRIA II GX FPGA 45K 780FBGA
• Manufacturer: Altera
• Series: Arria II GXr

Specifications of EP2AGX45DF29I5

• Number Of Logic Elements/cells: 42959
• Number Of Labs/clbs: 1805
• Total Ram Bits: 3435
• Number Of I /o: 364
• Voltage - Supply: 0.87 V ~ 0.93 V
• Mounting Type: Surface Mount
• Operating Temperature: -40°C ~ 100°C
• Package / Case: 780-FBGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Number Of Gates: -

4–28
Table 4–6. Example of Round-To-Nearest-Even Mode
Table 4–7. Comparison of Round-to-Nearest-Integer and Round-to-Nearest-Even
Arria II Device Handbook Volume 1: Device Interfaces and Integration
6- to 4-bits Rounding
Rounding and Saturation Mode
010111
001101
001010
001110
110111
101101
110110
110010
Round-To-Nearest-Integer
010111
001101
001010
001110
110111
101101
110110
110010
Rounding and saturation functions are often required in DSP arithmetic. Rounding is
to limit bit growth and its side effects; saturation is to reduce overflow and underflow
side effects.
Two rounding modes are supported in Arria II devices:
■
■
You must select one of the two options at compile time.
The round-to-nearest-integer provides the biased rounding support and is the
simplest form of rounding commonly used in DSP arithmetic. The
round-to-nearest-even mode provides unbiased rounding support and is used where
DC offsets are a concern.
mode. Examples of the difference between the two modes are shown in
this example, a 6-bit input is rounded to 4 bits. You can observe from
the main difference between the two rounding options is when the residue bits are
exactly half way between its nearest two integers and the LSB is zero (even).
Round-to-nearest-integer mode
Round-to-nearest-even mode
➱
➱
➱
➱
➱
➱
➱
➱
Odd/Even (Integer)
0110
0011
0011
0100
1110
1011
1110
1101
Even (0010)
Even (1100)
Odd (0011)
Odd (1101)
×
×
×
×
Table 4–6
Fractional
> 0.5 (11)
< 0.5 (01)
= 0.5 (10)
= 0.5 (10)
> 0.5 (11)
< 0.5 (01)
= 0.5 (10)
= 0.5 (10)
lists an example of how round-to-nearest-even
Round-To-Nearest-Even
Add to Integer
010111
001101
001010
001110
110111
101101
110110
110010
Chapter 4: DSP Blocks in Arria II Devices
1
0
0
1
1
0
1
0
Arria II Operational Mode Descriptions
December 2010 Altera Corporation
➱
➱
➱
➱
➱
➱
➱
➱
0110
0011
0010
0100
1110
1011
1110
1100
Table 4–7
Table
Result
0110
0011
0010
0100
1110
1011
1110
1100
4–7. In
that