How much power is needed?

HiFive Unmatched
1

i prepare to recieve sifive unmatched .

please teach

  1. how much power supply (watt)
  2. the shape of the ATX
2

I don’t have information on the power requirements.

However, if your second question is about the shape of the system board, it’s a Mini-ITX;

Wikipedia - Mini-ITX

3

The Unmatched Getting Started Guide on our web site says it needs a 250W power supply minimum, but I suspect this is worst case assuming that every I/O port is filled with a device drawing power near the limit, plus a little extra to be safe.

Visit https://www.sifive.com/boards/hifive-unmatched and scroll down to the Getting Started Guide.

There is also U740 chip documentation there too.

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4

The Getting Started Guide does say 250 watts, but the document above it, the HiFive Unmatched Product Brief states on page 2 “150W ATX Power Supply (sold separately)”

5

I think the Getting Started Guide is more up to date than the Product Brief. I sent an internal message to try to get the product brief updated.

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6

The Getting Started Guide has just been updated to v1p1 and is available here:

The document has been updated to reflect that the PSU must be rated at a minimum of 150W.

Apologies for the confusion.

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7

The minimum power supply is 150W but I suppose, like for a PC, this doesn’t mean it will continuously draw that much.

Has anyone made measurements of actual power draw of the SiFive Unmatched board (with minimal hardware attached)?

8

If it’s anything like the Unleashed and the BeagleV beta board (same U74 cores) it will be around 5 or 6 W.

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