OR2T15B7BA352-DB View Datasheet(PDF) - Lattice Semiconductor

Part Name

Description

Manufacturer

OR2T15B7BA352-DB

ORCA® Series 2 Field-Programmable Gate Arrays

Lattice Semiconductor

OR2T15B7BA352-DB Datasheet PDF : 200 Pages

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ORCA Series 2 FPGAs

Data Sheet

November 2006

Programmable Logic Cells (continued)

independent functions of up to ﬁve inputs is shown in

Figure 5. In this case, the LUT is conﬁgured in the F5A

The LUT ripple mode operation offers standard arith-

and F5B modes. As a variation, the LUT can do one

metic functions, such as 4-bit adders, subtractors,

function of up to ﬁve input variables and two four-input

adder/subtractors, and counters. In the ORCA

functions using F5A and F4B modes or F4A and F5B

Series 2, there are two new ripple modes available. The

ﬁrst new mode is a 4 x 1 multiplier, and the second is a

4-bit comparator. These new modes offer the advan-

tages of faster speeds as well as denser logic capabili-

S ties.

When the LUT is conﬁgured to operate in the memory

mode, a 16 x 2 asynchronous memory ﬁts into an

E HLUT. Both the MA and MB modes were available in

previous ORCA architectures, and each mode can be

conﬁgured in an HLUT separately. In the Series 2,

IC there are two new memory modes available. The ﬁrst is

D a 16 x 4 synchronous single-port memory (SSPM), and

the second is a 16 x 2 synchronous dual-port memory

(SDPM). These new modes offer easier implementa-

V E tion, faster speeds, denser RAMs, and a dual-port

capability that wasn’t previously offered as an option in

the ATT2Cxx/ATT2Txx families.

E U If the LUT is conﬁgured to operate in the ripple mode, it

cannot be used for basic combinatorial logic or memory

D functions. In modes other than the ripple, SSPM, and

IN SDPM modes, combinations of operating modes are

possible. For example, the LUT can be conﬁgured as a

16 x 2 RAM in one HLUT and a ﬁve-input combinatorial

T logic function in the second HLUT. This can be done by

T conﬁguring HLUTA in the MA mode and HLUTB in the

F5B mode (or vice versa).

C N F4A/F4B Mode—Two Four-Input Functions

E Each HLUT can be used to implement two four-input

O combinatorial functions, but the total number of inputs

into each HLUT cannot exceed ﬁve. The two QLUTs

L within each HLUT share three inputs. In HLUTA, the

E C A1, A2, and A3 inputs are shared by QLUT2 and

QLUT3. Similarly, in HLUTB, the B1, B2, and B3 inputs

are shared by QLUT0 and QLUT1. The four outputs are

S IS F0, F1, F2, and F3. The results can be routed to the

D0, D1, D2, and D3 latch/FF inputs or as an output of

the PFU. The use of the LUT for four functions of up to

D four inputs each is given in Figure 4.

modes.

QLUT3

QLUT2

QLUT1

QLUT0

HLUTA

HLUTB

5-2753(F).r2

Figure 4. F4 Mode—Four Functions of Four-

Input Variables

WEA

WD3

WD2

WPE

A3 QLUT3

A1 QLUT2

WD3

WD2 c0

B3 QLUT1

B1 QLUT0

HLUTA

HLUTB

F5A/F5B Mode—One Five-Input Variable Function

Each HLUT can be used to implement any ﬁve-input

combinatorial function. The input ports are A[4:0] and

B[4:0], and the output ports are F0 and F3. One ﬁve or

less input function is input into A[4:0], and the second

ﬁve or less input function is input into B[4:0]. The

results are routed to the latch/FF D0 and latch/FF D3

inputs, or as a PFU output. The use of the LUT for two

5-2845(F).r2

Figure 5. F5 Mode—Two Functions of Five-Input

Variables

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