HP SAS expander

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ghost6303

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http://pinouts.ru/Slots/pci_express_pinout.shtml

does anyone happen to know exactly which pins this expander card uses from the PCIE connector? ive read of several people using junk motherboards simply to power the card, and figure there should be a better way. if anyone can point me in the right direction i would appreciate it (you all might as well, if what i have in my head works out).

tl;dr {what PCIE pins on the expander card are necessary for its operation? only power pins and grounds? pwrgood or reference clocks as well?}
 
more or less answered some of my own question already, but if anyone has information regarding the behavior of the power good signal, or if the reference clocks are used, or any other datasheets you would like to share....
 
Thanks nitro :)

To the OP: If you are considering making an adapter or simply wiring some cables to a PCIe connector, you will need to supply power to the expander as well as the powergood signal. You could use the powergood signal straight off the power supplies ATX connector, however I would suggest you run it through a schmitt trigger buffer to guarantee clean fast rising and falling edges of the powergood signal.

It's been a while since I last looked at the actual pins used by the adapter. IIRC, you will need to supply +12V and +3.3V (including the +3.3Vstandby), as well as the PWRGD signal and of course GND. That should be all you need to run the card in a standalone environment.

Hope this helps.
 
nitrobass24 said:
Look up treadstones build log.
Click to expand...

thats where i read it before! thanks for the link, couldnt remember where it was. wasnt in the expander thread...

@treadstone- yes that is very helpful. though you said in your thread that PWRGD signal was 3.3v, though the ATX PWR_GD is 5v from what i can find. does that matter to the expander? or is it simply looking for a steady positive voltage on that pin to keep the chip out of reset (or looking for a short to ground to initiate a reset), do you think? a schmitt trigger is probably a good idea.

@nitro- good link, and that is similar to what i wanted, but what i have in mind would be both cheaper (hopefully, since it doesnt need to be full length 16x or have all those other connectors), simpler and more specifically tailored to what we would be using it for. im not really looking to mass produce this, though il make a few if people want. a friend of mine in IT was working on a few storage boxes and we got to talking about this. i told him my idea and he said he would buy a dozen if i made em, so im looking into it....
 
@ghost6303: you are correct, here are the PWR_OK Signal Characteristics according to the ATX power supply guidelines:

PWR_OK Signal Characteristics
Signal Type +5 V TTL compatible
Logic level low < 0.4 V while sinking 4 mA
Logic level high Between 2.4 V and 5 V output while sourcing 200 &#956;A
High-state output impedance 1 k&#937; from output to common
PWR_OK delay 100 ms < T3 < 500 ms
PWR_OK risetime T4 &#8804; 10 ms
AC loss to PWR_OK hold-up time T5 &#8805; 16 ms
Power-down warning T6 &#8805; 1 ms

I don't know if the PWRGD input signal on the HP SAS expander is 5V tolerant. But to be on the safe side, you can either put a voltage divider or a resistor and zener on this signal to limit the high level. Or you could use a 5V tolerant schmitt trigger buffer powered of the 3.3V which will also solve this problem for you...

I was going to design a small PCB with a PCIe and ATX power connector on it to power an HP SAS expander for use in external enclosures along with a simple circuitry to use a push button to control the ATX power on/off function. I could have that whipped up in a few minutes. If there is enough interest I would get a PCB manufactured. I do this on a regular basis anyway :)
 
treadstone said:
I was going to design a small PCB with a PCIe and ATX power connector on it to power an HP SAS expander for use in external enclosures along with a simple circuitry to use a push button to control the ATX power on/off function. I could have that whipped up in a few minutes. If there is enough interest I would get a PCB manufactured. I do this on a regular basis anyway :)
Click to expand...

i think you'd sell more than you realize. put me down for 10 :) why don't you post about it in the official thread to gauge interest, i can also stick it in the OP.

btw, not sure why we need multiple threads on the hp expander since that fragments the information, but whatev - this forum is 90% redundant threads anyway.
 
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treadstone said:
...
I was going to design a small PCB with a PCIe and ATX power connector on it to power an HP SAS expander for use in external enclosures along with a simple circuitry to use a push button to control the ATX power on/off function. I could have that whipped up in a few minutes. If there is enough interest I would get a PCB manufactured. I do this on a regular basis anyway :)
Click to expand...
Make sure you include a relay to turn the ATX power on/off with a +5v trigger. That way you can run a +5v lead from another chassis and remotely turn it on w/out directly connecting the PSU in one case to the other (considered a good thing as long as your goal is not starting a fire).
 
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