Logi-Pi vs pif?

jiapei100

Hi, all:

I did a search "raspberry pi fpga" on google, and I got 2 products:

Logi-pi and pif

http://www.bugblat.com/products/pif/

So, did anybody carry out a comparison between these two?

What are their performance?

Cheers

Pei

jpiat

Hi Pei,

the pif and the LOGI-pi are both FPGA based extansion for the raspberry-pi, but i'll try to sum-up the differences :

LOGI-PI is Xilinx based while Pif is Lattice based
LOGI-PI FPGA has 5270 6-input LUT while the biggest PIF has 6864 4-input LUT (comparing the LUT is not enough the logic elements of Lattice and Xilinx are quite differents.)
LOGI-PI FPGA has 64 9K block-ram while the biggest PIF has 26 9k block RAM
LOGI-PI FPGA is SRAM based while the PIF is flash based (consumes less power)
LOGI-PI board has SDRAM (64MB) while the PIF has not external RAM

LOGI-PI has 16Mbit onboard Flash while the PIF has 256kbit

LOGI-Pi has 2x pushbuttons and 2x dip switches while the PIF has none

LOGI-Pi has 2x LEDs  - PIF has 2x LEDs
LOGI-PI has 4x PMOD compatible connector while PIF breakout all the IO on a 13 pin and a 8 pin connector (no standard)
LOGI-PI has 1x Arduino compatible (3.3v only) connector while the PIF does not
LOGI-PI has a SATA connector for fast differential IO and two of the PMOD are routed with differential IO while the PIF does not advertise differential IOs
LOGI-PI uses a 4-layer PCB to ensure good signal integrity (no word on the PCB on the PIF website)
LOGI-PI has mounting holes matching the raspberry-pi mounting holes to make sure your LOGI-PI stays level.
LOGI-PI is 89$ while the biggest PIF is 34.99$

I'am sure the PIF is a nice board to experiment with the raspberry-pi and FPGA, but regarding the specs, it seems to target a smaller subset of application than the LOGI-PI (due to memory and differential signaling mainly). With the LOGI-board we also try to provide a large repository of demo and IP such as the wishbone based peripheral and wishbone wrapper for each of the LOGI platforms. Maybe someone owning the PIF could also give feeback on this forum.

regards,

Jonathan Piat

jiapei100

Thank you so much Jonathan Piat.

It's already quite clear.

Just wondering if they can send LOGI products to the mainland of China?

Cheers

Pei

mjones

Hi @jiapei100 thanks for dropping in to say hello and sharing your great question.

I just wanted to add a few words to what Jonathan has shared.  The big picture design of the LOGI boards is to make using as simple as possible.  There are many pit falls and difficulties in using FPGAs and we have tried to simplify and ease the process to ensure that the end user from beginners to engineers are successful the first time around.  Some of the challenges of working with include learning and understanding the concepts of working with FPGAs, writing the HDL code successfully, connecting external to hardware peripherals, programming the FPGA and finally making everything work together.  We have tried to address as many of complexities of using the FPGA to make the experience for users as seamless and straightforward as possible.  

We have designed the LOGI boards to be used to be used in a maximum number and wide array of applications with the included onboard peripherals.  The PMOD and arduino expansion headers give you access to 400+ off the shelf hardware modules. This allows users to easily move from application to application by simply plugging in the new hardware programming the FPGA and moving along.  I personally have pulled out many a hair and burned up many a board trying to create my own custom external modules by soldering and wiring together perf and breadboards.  It can certainly be done, but in the end it is nice having the option to plug it in and go.  

We are also focused on the educational aspect of getting users comfortable in working with FPGAs.  There are basic fundamentals that need to be addressed before a user can successfully begin doing their own work with FPGAs.  I graduated with an EE degree and still felt pretty useless when introduced to the real world of FPGA use.   We hope to provide minimal theory and maximal access to projects and applications that will ensure that users can be successful in their experience with FPGAs.  For the LOGI-Pi we provide the LOGI-EDU expansion board that supports the examples and projects from the Pong Chu books on verilog and VHDL.  These books are provide a very professional and fun walk through on all of the critical aspects of using FPGAs.  It is critical that users become educated with these concepts in order to be successful in working with FPGAs on their own.  We hope to eventually provide an open source version of FPGA learning material by pulling together current and newly created content from hamster's FPGA and augmenting with our own material.  This will take some time so in the mean time the Pong Chu books are a great resource.  

We provide a number of ways for users to experience FPGAs ranging from simply plugging in the modules and programming our pre-written code and having applications such as blinking leds, machine vision, VGA video games and many more just run.  These are what we refer to as the LOGI-Apps.  We provide all of the source code and and drivers for these apps in our repositories so that users can begin creating their own projects after becoming comfortable and proficient with working FPGAs.  Additionally we have developed a new graphical approach of programming FPGA in a drag and drop manne, see the LOGI Skeleton editor page for more details.  Or you can experiment with it directly live on our webpage here.  

Anyhow, I'll get off of the soapbox, but just wanted to paint the bigger picture of what we are trying to do with the LOGI boards and clarify how they might optimize your experience with FPGAs.  This is the just the start and based upon our own experiences with FPGA.  We look forward to hearing from you what you would feel is need and would like to see happen in enhancing your experience with FPGA!  

Cheers,

Mike