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Problem background: My ultimate aim is to implement a SATA host controller on an Artix 7 FPGA. Having said that I am first focusing on the physical layer. Through my research I have found and read through open source IP located here: http://www.ecs.umass.edu/ece/tessier/rcg/virtex4-sata/sata_core.html

The IP described above is for an older family of FPGA devices and hence cannot be easily imported into the newer Vivado environment.

My question: Would it be better to start the physical layer from scratch using the 7-series transceiver wizard OR should I try to migrate bit by bit the old protocol to be used on the newer device?

Important notes:

  • Rocket IO transceivers are not supported in Vivado
  • The new device does not have a SATA output port itself like the ML405 board used for the open source core
  • From the product guide it seems like the 7-series transceiver wizard handles all the SATA physical layer things such as OOB, 8b/10b, comma detection etc. BUT there is no formal documentation or example design I can locate about SATA.
Voltage Spike
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sacco
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1 Answers1

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I wrote a SATA controller for a Spartan 6 and Virtex 6. It was not easy and it needs some work to be usable.

That said, I would suggest using Coregen to implement the Physical layer.

I found that there are quite a few registers that are not documented within the gigabit transceivers of the different FPGA generations. It's much better to follow the wizard. If I were going to start out on an Artix7 I would select the following:

Line Rate/RefClk Selection enter image description here

Encoding and Clocking enter image description here

Comma Alignment and Equalization enter image description here

PCIe, SATA, PRBS enter image description here

CB and CC Sequence enter image description here

Most of the selections are the default SATA 2 configurations but I chose to use 32-bit data bus.

Side note

Although you didn't ask I think this should be said:

While developing I wrote a simulated phy layer. It worked out really well because it both sped up development and I could disable the scrambler whenever I needed to.

Creating a simulated phy layer shouldn't be that bad. It really boils down to something like this interface:

module sata_phy_layer (

input               rst,            //reset
input               clk,

input               platform_ready,   //the underlying physical platform is
output              platform_error,
output              linkup,           //link is finished

output  [31:0]      tx_dout,
output              tx_is_k,
output              tx_comm_reset,
output              tx_comm_wake,
output              tx_elec_idle,
input               tx_oob_complete,

input   [31:0]      rx_din,
input   [3:0]       rx_is_k,  //I should have kept the rx/tx_is_k consistent 4 or 1 :/
input               rx_elec_idle,
input               rx_byte_is_aligned,

input               comm_init_detect,
input               comm_wake_detect,

output              phy_ready,
input               phy_error,
output      [3:0]   lax_state
);

I'm not here to support my old sata work, in fact I discourage it. There were some parts of it that I got working in a, shall I say... inelegant way.. but it might help if you are looking for a place to start.

SATA Project in Verilog

Dave
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