That depends on what you plug in. A bare system assuming ONLY the CPU and refresh current (not high-bandwidth usage) of the DRAM requires:

3.3V 800mA
5V 100mA
12V 20mA

Graphics card will be supplied by the 3.3V rail and the PCI specs have a maximum of 25W per card, hard disk by the 5V, check your required disk (could be as low as 1.8W, could be as high as 10W for spinup). USB is on the 5V rail, we would recommend you don't allow the power on that rail to go below 10W (after hard disk).

Add on your requirements there. Please be generous to the board - make sure you add some overhead

We already have specs for two or three suitable embedded 'open frame' power supplies. Most that spec to provide 50W provide more than enough current. It is ALWAYS safe to overspecify the power supply - remember if the board doesn't draw the current, it just doesn't draw the current, and a 50W supply will just run at a draw of 10W or 15W.

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Matt Sealey

From my experience the 12V rail (on the picopsu) has never had enough current on it to run 3.5" drives. Typically 2.5" drives are more limited in their capacity than 3.5" 'standard' drives and especially for a HTPC the more space the better.

These are the specs im looking at.
3.3V 3-5A (enough for the most power hungry cards)
5V 3-5A (USB devices do consume a bit of power)
12V 2A+ (The more the merrier)
(though 3A is seen as nominal supply current)

However I'm not quite sure about the needed current on the -12V rail

Please do not consider 3.5" drives, they are so out of scope for the EFIKA (they will draw 25-30x the power of the entire base system! What is the point of using a 1.08W board then?) and you CANNOT connect one to the internal 44pin connector for some VERY good technical reasons (no strange adapter cables please, due to the design of the MPC5200B, and the sharing of IO pins, ATA connector length has to be less than a certain size; the connector we have on the board fulfils this requirement)

If you are planning an ATA card in there or something to drive these disks, then you will obviously need to spec for it. But don't think about the internal ATA.
This depends on your PCI card, how old it is etc. - nothing on the board is connected to -12 unless you plug in a PCI card that has that connected. Some cards which do real video output (RF, SVideo, RGB) have line drivers which require symmetric +12 and -12 supplies. Most newer ones do not, however this is a decision of the guy designing the card.

For most normal usage; just use +3, +5, +12, ignore the other unless you have a special requirement on PCI.

The best way to spec a power supply and your requirements is to test; grab an EFIKA, plug all your devices in, and get your multimeter out and start looking at how the ATX connector is wired. You will get accurate load readouts there.

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Matt Sealey

I see Efika should also provide serial port (9-pin canon), the question is: is SmartFirmware also supported to work with this serial port as a serial console? I don't see any reason to connect USB keyboard/PCI/AGP graphics for embedded OS port in case this is supported...
Thanks,
Karel

kcg:
The serial port is used as a console/debug port
on the original Pegasos'es. I see no reason why
they would remove this from a development board.

Absolutely, positively, yes.

If you unplug a keyboard and display (either..) it will fall back there. If you wish to force it, the article in the PowerDeveloper articles list still works - as it does for ANY Open Firmware implementation.

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Matt Sealey

Ah, yes, true! Sorry, I've just seen the article now when you mentioned ``PD articles''! Thanks for the pointer, this is indeed cool so I don't need to hassle with useless USB keyboard. :-)
Thanks!
Karel

Now that the efika boards have landed... any news with regards to the possible selling of the PicoPSU?

Still working on it.

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Matt Sealey

Great. Sounds a lot better than 'forget it, kthxbye' :)