SATA on Stratix FPGAs

[Altera_Forum]

Hello Guys, 

 I was wondering if you share your valuable experiences and ideas with us regarding SATA implementation. I have an old STRATIX dev board and I want to implement SATA protocol on that to use SSD. AS this is kind of initial research project for a bigger project, our budget is kind of limited and I wont be able to buy higher end FPGAs at the moment. I looked at Altera website and notice that Stratix FPGAs are not listed in the list of FPGAs which support minimum 1.5Gbps SATA. on the website, I found out that Starix transceivers can achieve the speed of 840 Mbps which is considerably less that 1.5Gbps. I just want to know that if it is possible to force SATA to work in lower speed? if not, if we use external transceiver, can we achieve such a speed? in our system, the speed is not a bottleneck. the amount of storage which we need is a bottleneck. we currently use 64GB compact flash card and we can't use more than one CF card due to pin limitation and mechanical size availability. CF card uses 28 pins of FPGA and if we able to use SATA, we will be able to free some of those pins for other purposes. after we get some results from this, we will be able to migrate the design into Cyclone III FPGAs. please share your valuable experience and ideas. if you even point me to a document to help that would be brilliant.    many thanks, Aidan.

[Altera_Forum]

Hardware wise, SATA support requires at least 1.5 GBit transceivers and special out-of-band (OOB ) signalling features. Older Stratix GX devices have the GBit transceivers but not the OOB signalling. In addition, the SATA IP most likely hasn't been ported to these devices.  

 It might be possible to provide the OOB functionality by additional external hardware. In any case you need Gigabit transceivers (GX FPGAs). Apparently you have a Stratix device without GX blocks.  It should be noticed, that PATA-to-SATA converters are available as cheap plug-in adapters, so a SATA implementation in your FPGA design is not the only option to connect recent storage devices.

[Altera_Forum]

Thanks for your reply. Yeah, you are right. we have only Stratix device without GX Blocks. can we use external hardware to use Gigabit transceivers?(for example, in one of applications, we used Texas Instruments LVDS driver) can you point me to a document which describes SATA PHY requirements a bit in details. I have already googled it and it is kind of vague probably for me at this stage.  

 thank you.

[Altera_Forum]

SATA PHY requirements are described in detail in Serial ATA Specification, current revision is 3.2. www.sata-io.org 

 I still think that a parallel to serial ATA bridge is the most simple way to interface SATA to non-GX FPGA, particularly if you don't rely on the full SATA speed. You'll just implement a legacy PATA (IDE) storage device interface, the bridge does a transparent conversion.

[Altera_Forum]

Thanks, Yeah, I think that is a good starting point for us until we get a decent FPGA and implement the whole system in it. Bridge will increase the system power consumption . however. we will have to live with it until getting GX FPGA. Really appreciate your response

[Altera_Forum]

We successfully did a SATA implimentation using the DE4 board from Terasic and a SATA core from Inteliprop. 

 It worked well for our needs and Inteliprop was very responsive to our questions.  http://www.terasic.com.tw/cgi-bin/page/archive.pl?language=english&categoryno=138&no=501 http://www.intelliprop.com/  unless you are required to write your own SATA implimentation, a tested core is the way to go. It was pricey, but cheaper than it would cost to develope yourself.  I talked to a couple of other Core vendors at the time, and Inteliprop was quick in responding to our initial questions, and providing trial license to test it out.    Pete

[Altera_Forum]

Thanks Pete, The initial plan was to develop ourselves but as you well said it becomes too expensive. will contact them and ask for trial license to start with.