Answers Database

V1.5, V1.4 COREGEN, LOGIBLOX: Differences between COREGen and LogiBLOX,which modules are generated as RPMs


Record #3681

Product Family:  Software

Product Line:  Coregen

Problem Title:
V1.5, V1.4 COREGEN, LOGIBLOX:  Differences between COREGen and
LogiBLOX,which modules are generated as RPMs



Problem Description:
Keywords: core generator logiblox, coregen

Urgency: standard

General Description:
What are the differences between the LogiBLOX and
COREGen, and the functions supplied with them?


Solution 1:


INTEGRATION
-----------
The LogiBLOX GUI is integrated into Viewlogic
and Foundation flows, whereas the CORE Generator is currently
available only as a standalone tool.


FLEXIBILITY
-----------
LogiBLOX also allows greater flexibility in selecting which
pins will be present on a module.


RELATIVE CLB PLACEMENT (RPM/RLOC support)
-----------------------------------------
Another difference is that ALL cores generated with the CORE
Generator are relatively placed (for example, memories and
muxes).

(Note that in LogiBLOX v1.4, modules that utilize carry
logic such as adders and subtracters do use RLOCs, but only
to specify the how combinational logic is mapped into the
the same CLB with carry logic, not to specify relative
placement.)  This particular difference will disappear for
some additional modules in the M1.5 release, as RLOCs
will be used to constrain placement in LogiBLOX accumulator,
comparator, and counter modules as well.


RAM implementation:
-------------------
- COREGEN:  RAMs are 100% relatively placed, and single and
dual port RAMs of depth 64 or greater use TBUFs for
muxing/address decoding.

- LOGIBLOX:  In pre-M1.5 versions of LogiBLOX, RAMs are not
relatively placed.  In M1.5, the RAMs *will* be relatively
placed, but the associated address decode muxes will not be.

Also, LogiBLOX v1.5 will allow the user to specify the use of
TBUFs for muxing in RAMs, if desired.


THIRD PARTY MODULES
-------------------
The CORE Generator also differs in that it includes datasheets
for Xilinx PCI modules, and third-party AllianceCORE modules.


RECOMMENDATIONS
---------------
In general, functions that are available in both
CORE Generator and LogiBLOX should give better performance
using the CORE Generator implementation when the CORE
Generator implementation is relatively placed.	i

The main reason for using COREGen today is to get
access to new functions which are not supported by LogiBLOX,
such as:

  - square root function
  - multipliers
  - FIR filters
  - Comb filter
  - other DSP related functions

or to take advantage of the improved performance associated
with the use of relative placement constraints in COREGen.

If you do not need any of the functions supported
in the CORE Generator, you can continue to use LogiBLOX.

In a future release, the functions of both products will be
merged.



Solution 2:

					  LogiBLOX		     COREGen
					  ---------		  -------------
Accumulators				  Standard		  scale by 1/2
Adders					  Standard		   Registered
Clock Dividers				      X 			-
Comparators				      X 			-
Constants				      X 			-
Counters				      X 			-
Data Registers				      X 			-
Decoders				      X 			-
Inputs/Outputs				      X 			-
Memories				      X 			-
     Asynchronous RAM			      X 		   Registered
     Synchronous Dual Por		      X 		   Registered
     FIFO				      X 		   Registered
Multiplexers				Variable size		  2-, 3-, & 4-in
put only
Pads									-
Shift Registers 			      X 			X
Simple Gates				      X 			-
Subtracters				      X 		   Registered
Tristate Buffers			      X 			-
Parallel-Serial Converter	      Shift Register option		X


--------------------------------------------------------------------------------
------

COREGEN-only Functions
-----------------------
Time Skew Buffers			      - 			X
Sine-Cosine LUTs			      - 			X
PDA FIR 				      - 			X
SDA FIR 				      - 			X
Comb Filter				      - 			X
Registered Scaled Adder 		      - 			X
Complementer				      - 			X
Integrator				      - 			X
Square Root				      - 			X
Delay Element				      - 			X



End of Record #3681