Need advices on FPGA for telecom apps

[Altera_Forum]

Hi, 

I'm new to these forums so please let me know if this is the wrong place to post. I'm also quite new to the FPGA world (I've been using for 1 month a DE1 evaluation board with an Altera's Cyclone II 2C20 FPGA).  I need to develop a demonstrative board for a high-bandwidth (>30Mhz of baseband signal to process) telecom application. I'd like to have some advices about possible existing boards which contain high-performance FPGA + fast (>100MSPS) ADC + fast DAC (>100MSPS) + other misc required stuff (interface for FPGA programming, some Mbits of DRAM memory). I searched the web for vendors of such kind of boards but with no great success. Do you know if such kind of board is already available from some vendor? Where do you suggest me to look?  If such a board does not exist, I'm interested to develop a custom board (this would bring us the know-how for customizing in future more boards of this kind). However I'm a bit worried by the amount of work/testing which would require the design of a FPGA+ADC+DAC board from scratch (given that board would probably require > 4 layers, lots of support circuitry, etc). Could you point me to some existing resource (application note, open project, etc) which I could use as a start base?  I already have knowledge about the ADC/DAC I want to use since I tried to connect them with a DSP before trying the FPGA approach.  I'm used to EAGLE as PCB Layout tool and I've found some FPGA-related eagle projects here: http://www.jopdesign.com/board.jsp and I'm also looking at the "Prototype board" section at: http://www.opencores.org/projects Are there other good online resources I could dig into?  Thanks a lot! Francesco Montorsi

[Altera_Forum]

In the altera development kits (http://www.altera.com/products/devkits/kit-dev_platforms.jsp), you can have a look at the different DSP Development kits. They all have over-100MSPS converters.

[Altera_Forum]

--- Quote Start ---  In the altera development kits (http://www.altera.com/products/devkits/kit-dev_platforms.jsp), you can have a look at the different DSP Development kits. They all have over-100MSPS converters.  --- Quote End ---   Thanks for the hint. It turns out that I didn't look at the most obvious place, sorry. Indeed the DSP DevKits include suitable ADC/DACs!  I need to look into some other details however. For example the "DSP Development Kit, Cyclone II Edition" board features a 100Mhz on-board oscillator (even if it mounts a 165-MSPS DAC) and the possibility to provide an external clock.  If I'd need to use the DAC at its maximum performances (say 150MSPS) should I use an external clock source?  Thanks again! Francesco

[Altera_Forum]

There are some PLLs in the FPGAs, so you can generate higher clock rates if necessary. 

You will also need to determine if the Cyclone II will be powerful enough for your application. If you have started working on the internal design, you can try and compile it for different FPGA families and see how much resources you use and if your timing requirements are met.

[Altera_Forum]

Ok, thanks again for the info. 

Up to now I've never used the PLLs of my FPGA but it looks like I really need to learn how to use them :)  I'm now searching the "best buy" board among the DSP development kits of Altera; as you say I should have a raw idea of the resources required by the internal design of my project; since I have the project written as a MATLAB script, I'd first need to convert it to a Simulink model however.  AFAIK in fact, most telecommunication projects are developed using Simulink and then the Simulink => HDL coder => Quartus II chain. Could anyone confirm/deny this?  Another question which arises is: how to efficiently debug the board? For example if I create a program which takes data from the A/D, elaborates it and then stores it into memory, how can I read from a computer that memory, to test if the processing was ok?  Reading e.g. the "Cyclone II DSP Development Board reference manual", I see that for this scope, there are basically: - the USB-blaster cable connector (JTAG): in my DE1 board I never managed to use that for debugging, only for programming. From the reference manual it seems it's possible to use it as a general-purpose FPGA<->PC channel up to 1Mbps, instancing a specific IP core. Is it a good solution (i.e. something used in practice) for e.g. inspecting the board's memory contents? - the Mictor connector: this seems to be useful only for logic analyzer usage... - ASI connector: this one seems dedicated to programming only.  Thanks again for any precious hints! Francesco