By DragonMaster · 6 replies
Jun 20, 2005
  1. I'm planning to add a SATA HDD LED sometimes. I found the SATA connector pinout and I think that I could send the receive and transmit signal to a 7407(Buffer chip), that would then send the signal to the LED. Do you think it will work or you have no idea of what I'm talking about?
  2. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    You cannot.

    7407 is a TTL chip and it will not be able to recognise the LVD signals used by SATA.
  3. DragonMaster

    DragonMaster TS Rookie Topic Starter Posts: 327

    ! Found a bit of info about LVDS. 250mV instead of 700mV. Then, I just have to find a transistor that can do the job.

    Are there chances that the transistor will make the signal more prone to errors(Since the voltage will be a little bit reduced)? Will just using the + line or both make a difference?
  4. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    Actually the SATA LVDS uses a bias signal of ~500mV and data signals at ~125mV around it so we are talking about a signal that swings between ~400mV and ~600mV.

    Even if you adjust your circuit to those levels it will still not work since during idle periods a synchronisation signal (101010..) is put on the bus. You would need an intelligent device that could detect the difference between the sync signal and data transfers. And your circuit has to be able to work at the 1.5GHz speed SATA uses.

    You may have better luck looking for LED connectors on your hard drive or the motherboard/controller itself. Even if the pins are not there you might find the solder points.
  5. DragonMaster

    DragonMaster TS Rookie Topic Starter Posts: 327

    SiI tell that the Si3112A have some(And have application circuits), but my Adaptec 1205SA still has 4½ years warranty.

    The support is pretty bad at Adaptec tho : Latest bios and driver are from about december 2004 and driver on adaptec site is from january 2003. I modified the 1.2.?.? driver from the SiI SATALink card to give it the same name as the old driver but that's all.

    Soldering on the 3112 will be pretty hard.

    And also, if the sync signal looks darker on the LED, I don't have pretty much problems with this. I could add a small capactor somewhere to make this 010101 seem a lower voltage, and then add a resistor to pass it to a 7407 but I don't know if it will be accurate.

    I just don't want to lose my warranty, that's the problem. The card is 4 months old and even my local shop still has a warranty. I would prefer to cut a SATA cable and to get the signal from there instead.

    Maybe there is a connector on the HDD. Will have to ask WD. A Maxtor is cool for this : since Quantum HDDs and maxtors are the same thing, there's always a little SMD HDD status LED under them. You just need a photoresistor to make the thing work.
  6. edgecase

    edgecase TS Rookie

    SATA Activity LED was added to specs - pin 11 of power connector

    This SATA hotswap chassis uses power connector Pin 11:

    These are better than the Supermicro ones I have (the activity LEDs have to be driven externally) , because they
    support drive fail LED also. I can drive those from a standard PC parallel port if a RAID card doesn't provide them.

    Electrical specs are on page 15:

    In any case, it can "sink" 300uA "micro-amps" max, so you'll need a low power buffer to drive an LED (7407 draws too much even, and it's a TTL interface so normal CMOS won't work either) - a typical surface mount LED takes about 13mA. I'm modifying a SuperMicro CSE-M35T-1 for this purpose so I'll try to post here when I've found a suitable buffer.
  7. DragonMaster

    DragonMaster TS Rookie Topic Starter Posts: 327

    Was it there with SATA I?
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