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OMAP-L138 SATA Interface - clock and data termination

fdm
Expert 1070 points
Other Parts Discussed in Thread: OMAP-L138, PMP

Hi,

The  OMAP-L138 DS (sprs586b) shows the SATA interface schematic at section 6.14.2.1, figure 6-30. There are no termination resistors (external or internal) shown at both differential data and clock signals.

However the TI EVM and Hawkboard schematics both have the 100 Ohm parallel termination resistor at the SATA_REFCLK input.

So does the OMAP-L138 have internal termination resistors at the SATA clock and/or data inputs?

 

  • 0
    TI__Mastermind 27585 points

    The OMAP-L138 itself has the parallel terminator built in, so the external terminator is not necessary. In case of discrepancy, always follow the datasheet rather than the EVM or community board.

    Jeff

  • 0 in reply to jc-ti
    Expert 1070 points

    Thank you, Jeff!

    Unfortunately, there is no model for the SATA interface pins in the current revision of IBIS file available on the TI site.

    What is the nominal (target) value of internal parallel terminator at the SATA_REFCLK input? Can I assume for modeling purpose that value is exactly 100 Ohm?

  • 0 in reply to fdm
    TI__Mastermind 27585 points

    Yes it is a 100 ohm parallel terminator you can use to model.

    Jeff

  • 0 in reply to jc-ti
    Prodigy 140 points

    Should the external 100 ohm resistor on the LogicPD board (R68) be removed for proper SATA operation?  I am seeing many SATA bus errors.

     

    Thanks,

    Rick

     

  • 0 in reply to Rick Rogers
    TI__Mastermind 27585 points

    Yes early LogicPD boards have issues with the SATA interface for a variety of reasons, this included. The latest revision has fixed the issue through both component and layout changes. You may not be able to get the interface to work with that revision of the SOM.

    Jeff

  • 0 in reply to jc-ti
    Expert 1070 points

    jc said:
      ... The latest revision has fixed the issues with the SATA interface...

    There is only early revision of design files currently available at the LogicPD site. Where can the latest revision of these files be obtained?

    Best regards,

    Denis

     

  • 0 in reply to fdm
    TI__Mastermind 27585 points

    You should ask LogicPD this question. From my login I see design files for the SOM dated 1/7/2011. 

    Jeff

  • 0 in reply to jc-ti
    Expert 1070 points

    Jeff,

    Sorry for inconvenience - these updated design files have become available after product registration update and they have already fixed the SATA_REFCLK terminator issue.

    Thank you for assistance.

    Denis

  • 0 in reply to jc-ti
    Prodigy 140 points

    Jeff,

     

    Could you please provide more detail into all the issues you alluded to with the SATA interface of the early SOM's?  I removed the 100ohm clock termination resistor on a 1013xxx version SOM, but still get errors reported by the linux SATA driver.  I am trying to work with Logic to get the issue resolve, but need details to ensure it is not a driver issue.  To note, I also ensured the IO voltage on the L138 dev board is selected to 3.3V and the Port Multiplier option of the driver is disabled.

     

    Thanks,

    Rick

     

  • 0 in reply to Rick Rogers
    TI__Mastermind 27585 points

    Can you give a log of the errors you are seeing in Linux? Also can you give the part number for the HDD you are using? It could very well be a driver issue.

    For the current revision of the board Logic has removed that terminator, corrected the values of the coupling capacitors to match the datasheet, and made layout changes that affect the SATA clock and data pins.

    Jeff

  • 0 in reply to jc-ti
    Prodigy 140 points

    Jeff,

    Below are the errors reported upon modprobe ahci.  The same errors are reported for two different SATA drives : SSDSA1M160G2N 1.8" 3Gb/s SATA SSD  160GB 3.3V 1A, and RiDATA SATA 2 Flash Drive 2.5" 128GB Ultra S (model NSSD-S25-128-C04M-PN).

    root@l138:~# modprobe ahci
    ahci ahci: forcing PORTS_IMPL to 0x1
    ahci ahci: AHCI 0001.0100 32 slots 1 ports 3 Gbps 0x1 impl SATA mode
    ahci ahci: flags: ncq sntf pm led clo only pmp pio slum part ccc
    scsi0 : ahci
    ata1: SATA max UDMA/133 irq 67
    ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
    ata1.00: ATA-7: INTEL SSDSA1M160G2GN, 2CV102HD, max UDMA/133
    ata1.00: 312581808 sectors, multi 1: LBA48 NCQ (depth 31/32)
    ata1.00: configured for UDMA/133
    scsi 0:0:0:0: Direct-Access     ATA      INTEL SSDSA1M160 2CV1 PQ: 0 ANSI: 5
    sd 0:0:0:0: [sda] 312581808 512-byte logical blocks: (160 GB/149 GiB)
    sd 0:0:0:0: [sda] Write Protect is off
    sd 0:0:0:0: Attached scsi generic sg0 type 0
    sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
     sda:
    ata1.00: exception Emask 0x12 SAct 0x1 SErr 0xa80500 action 0x6 frozen
    ata1.00: irq_stat 0x08000000, interface fatal error
    ata1: SError: { UnrecovData Proto 10B8B BadCRC LinkSeq }
    ata1.00: failed command: READ FPDMA QUEUED
    ata1.00: cmd 60/08:00:00:00:00/00:00:00:00:00/40 tag 0 ncq 4096 in
             res 40/00:04:00:00:00/00:00:00:00:00/40 Emask 0x12 (ATA bus error)
    ata1.00: status: { DRDY }
    ata1: hard resetting link
    ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
    ata1.00: configured for UDMA/133
    ata1: EH complete
    ata1: limiting SATA link speed to 1.5 Gbps
    ata1.00: exception Emask 0x2 SAct 0x1 SErr 0x1080400 action 0x6 frozen
    ata1: SError: { Proto 10B8B TrStaTrns }
    ata1.00: failed command: READ FPDMA QUEUED
    ata1.00: cmd 60/08:00:00:00:00/00:00:00:00:00/40 tag 0 ncq 4096 in
             res 40/00:04:00:00:00/00:00:00:00:00/40 Emask 0x6 (timeout)
    ata1.00: status: { DRDY }
    ata1: hard resetting link
    ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
    ata1.00: configured for UDMA/133
    ata1: EH complete
     sda1
    sd 0:0:0:0: [sda] Attached SCSI disk
    sda: detected capacity change from 0 to 160041885696
    root@l138:~# FAT: bogus number of reserved sectors
    VFS: Can't find a valid FAT filesystem on dev sda.
    EXT2-fs (sda1): warning: mounting unchecked fs, running e2fsck is recommended

     

    Thanks,

    -Rick

  • 0 in reply to Rick Rogers
    TI__Mastermind 27585 points

    Rick, there is a new patch out which fixes the PHY settings to work with more SATA drives. Can you give this a try and let me know if it helps? Thanks

    http://arago-project.org/git/people/?p=sekhar/linux-omapl1.git;a=commit;h=03933093267265f64a175ac7e1c2ecdd2a398d2f

    Jeff

  • 0 in reply to jc-ti
    Prodigy 140 points

    Jeff,

    Made the change per the patch provided.  Still only getting ~15-17MB/s writes to ext2 formatted drive (iozone used for benchmarking).

    I got an updated L138 SOM (1016xxx rev)- the previously reported errors are no longer generated upon ahci module insertion- though I'm still using a 1013xxx EVM baseboard. 

    According to this link: http://processors.wiki.ti.com/index.php/DaVinci_PSP_03.20.00.14_Device_Driver_Features_and_Performance_Guide#SATA, sata benchmarks should be >20MB/s (at 99% cpu, 300MHz).  Still trying to figure out why I can't achieve the same...

    -Rick