fractal

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  1. I never called you a liar. I was suggesting that making statements in BOLD like MORE THAN 12 VOLTS, WILL BE FRIED, WILL BE USELESS are not constructive. I fend many comments from people who got back from the store with their shiny new DVM and immediately post "I JUST MEASURED MY POWER SUPPLY AND IT IS SUPPOSED TO BE 12 VOLTS AND IT IS 12.4312345 VOLTS! I AM AFRAID!!" I refrain from asking them not to post voltages to 6 digits and comfort them that 12 1/2 volts is fine. I agree with you that it is silly to buy cheap, buy twice. And that it is not wise to buy a cheap power supply. That may be why I have a HP 6281A supply on the desk next to me powering my latest little board. But, that does not mean I was suggesting you were telling a falsehood when I noted that modern computer equipment has a wider tolerance for input voltage than you indicated. Due diligence and caution are justified. Crappy power supplies are the bane of us all. But can we please keep it to the level of appropriate caution and not try to entice uncertainty and doubt where not needed? I bought a power brick a few years ago that provided 12V 2A and 5V 2A on a 4 pin molex plug. I use it when I am running a hard drive on the bench with a usb->sata dongle. I just checked and Amazon sells them for 15-20 USD. Something like that might be a better choice for running a hard drive than combining two separate supplies, especially since that is what it is designed for. There is nothing inherently wrong with using two supplies or using a regulator to drop 12V to 5V if you are handy and so inclined. I just found it more convenient to have a single block plugged in to run power the drive instead of having two and a mess of wires to convert the outputs.
  2. Owwie. Not sure if I should respond to this FUD, but.. Please see http://www.seagate.com/staticfiles/docs/pdf/datasheet/disc/desktop-hdd-data-sheet-ds1770-1-1212us.pdf These common 3 1/2 drives wants +5v +- 5% and +12v +10%,-7.5%. Let me do the math. That's 4.75V -> 5.25V and 11.1V -> 13.2V. Now, i don't recommend the cheap power supplies without a proper, non-forgery UL rating out of caution, but a hard drive is a little more resilient than some people think.
  3. I plugged the fan into the end two pins on the serial connector to get +5/gnd. It helps. I am crunching away with 4 cores of cpuminer with temperatures sitting at 65c and clock pretty steady at 1104 Mhz, one step down from the peak 1152.
  4. I love the C2. Too bad its SOC lacks the aes crypto extensions. It is currently my favorite modern little board. I probably wouldn't bother with 64 bit ARM in a production project unless I needed enhanced crypto, but it looks to me like that architecture is going to get more of the good stuff going forward.
  5. I purchased a nano-pi m3 to play with a cheap 8 core arm board and figured I would share my experiences. Much of what I found matches what is posted on this thread but not all. I have not set up a dedicated SBC bench yet so I bring boards up in my mobile area since it is the only place with a spare HDMI cable. I use a good power supply with a long, crappy micro usb cable. A pine-64+ lives there under full load in a constant state of thermal limit. Let's see how long it takes to burn it out. But that is a different post, this one is about the M3. Initial bringup was a breeze. Mount the optional HSF, flash the sdcard and plug it all in. It took three tries to get the fan plug on the right way as usual. Only two ways to plug it in but it always takes three tries. Not sure why. The board came up just fine, idle temperatures were fine. Everything looked good. So down comes multi-miner for a bit of a stress test. Fire it up and temperatures quickly peak and it goes into thermal limit. Less than a minute later it crashes. I repeat this a few times before I see a pattern. Not needing the HDMI any more I move the board to my SBC pile with an Anker 60 watt, 6 port usb charger and short, high power USB charging cables. I inserted a USB doctor between the charger and the cable. I started it up and connected via SSH. Idle power consumption was a bit higher than the other SBC's. I start the miner and temperatures quickly peak and the board goes into thermal limit. USB doctor reports 1.5 amps of current draw. Three and a half days later it is still running. I have no problems running the NanoPI M3 from the micro usb cable when I use a sensible power supply and sensible cable. It crashes and burns about as you would expect if you use a silly wimpy little cable you found in your sock drawer that you love since it is nice and long and gets from the wall wart behind your bed to your night stand where you charged your phone. root@NanoPi3:~# w 05:06:33 up 3 days, 16:51, 2 users, load average: 8.87, 8.88, 9.02 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT fa :0 :0 Wed12 ?xdm? 3days 0.24s /usr/bin/lxsession -s LXDE -e LXDE root pts/0 x.x.x.x Wed12 1.00s 0.39s 0.01s w root@NanoPi3:~# cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state 1400000 29541406 1300000 0 1200000 0 1100000 12 1000000 0 900000 3 800000 1226558 700000 1218579 600000 352 500000 239 400000 9521 My main concerns with this board are that is fails to gracefully slow down. It is alternating between 700, 800 and 1400 MHz. The pine64 I am abusing has settled down to alternating between 960 and 1080 MHz. This feels a bit more sensible than what the M3 is doing. I know it is only software to fix it so I have started down the path of building my own image. I have set up the cross tool chain and built everything so now all I have to do is tweak it.. I am a bit disappointed with the FA provided HSF. The fan is loud and ineffective and the processor overheats. I suppose this is better than the HSF offered with the Pine64 (none). The heat sinks that come with the Odroid's are much better. My C2 does thermal limit a bit running the miner but that is with the board in the optional plastic box. Probably my biggest annoyance is the lack of a 64 bit OS. I really wanted the 64 bit extensions for mining / boinc. Though, given the weak cooling I suspect the lower performing kernel is a blessing in disguise.