Power supply sensitivity?

[aolofsson]

Yesterday we played around with a USB supply rated at 2A connected yet the micro-usb connector next to the rj45 Ethernet port. Sadly the best at failed to load the FPGA bit stream (probably because this requires peak current..we'll provide a current signature soon.)
Fortunately the USB wall wart also had a secondary USB output. That one worked!

Clearly we need to take a look at the board to see if there is something we can do to see improve the situation. Until then, please mak sure you use a supply with a 2A rating AND a short fat cable. To be safe..we still recommend that you buy an accessory kit that has been tested with the board.

[StarfirePrime]

I've been playing with my Parallella on and off for a couple of weeks. Unfortunately, I'm having several sporadic issues (that others have reported). Unreliable USB operation with kb/mouse with and without a powered hub (I'm using a Logitech wireless combo so I can't believe it's drawing much power). Usually I ssh into the board. e-test works find and matmul-16 runs fine for single iterations. Other demo apps, even simple ones seem to hang the board. No idea about that. I've notice that trying to compile some examples, I'm occasionally getting missing header references and missing symbols at linking. So there may be something in my setup. However, I'm using the sd image provided on the Parallella site.

I have tried using a 5V/2A (HP Touchpad) USB supply (made my own cord) and also tried a 5V/2A wall wart (changed the tip to fit) and I get the same behavior. I'm guessing that when the board goes to draw more power, it's not there (?). I have a variable, bench power supply that I was going to try next (but I need another tip).

Do you think 2A is a minimum?

[aolofsson]

2A should definitely be fine if it's a real 2A with a good cable. Most if the time we have run between 0.9A and 1.35A.(depends on load and what is connected on he USB port).

Do you have a fan pointed at the board?
(Overheating is the second most common issue)

[StarfirePrime]

Yes, I have a 60mm fan right over the top of the heatsink and epiphany chip (no sink). The xtemp program shows the idle temp @ 50C when I drive the fan with 12V and 59C when I pull it back to 5V.