Raspberry Pi Lab

Archive for April, 2014

Overclocking the RPi

by on Apr.13, 2014, under Installation

The RPi runs at a default speed of 700 mhz.  I don’t know about you, but that is a bit slow for my tastes.  While I understand that overclocking does generate additional heat and does reduce the life of the device, I am willing to take that risk to get a lttle more speed out of my RPi.  After all at a price of $35 USD, I can afford to replace one occasionally.

The overclocking can be done from the ‘sudo raspi-config’ utility.  However, the real settings are in the file “/boot/config.txt”.

Just for those who aren’t aware… the RPi does NOT have a BIOS.  Therefore the base paramaters that would normally be loaded from a BIOS are moved to the filesystem of the SD card on “/dev/mmcblk0p1”.  This file system is mounted in the OS as “/boot”.

First, make a copy of your “/boot/config.txt” file with “sudo cp /boot/config.txt config.txt.original”.  It’s always good practive to back-up a file before monkeying around with it.

I tried pushing my RPi to the 1 ghz max clocck speed, but it did not work.  The system immediately crashed.  So I resored my config.txt file, re-booted and tried again.  This time I configured it for 950mhz.  This setting has been working for about 48 hours without issue.

Here is the relevant portion of my /boot/config.txt file…

#uncomment to overclock the arm. 700 MHz is the default.
arm_freq=950

# for more options see http://elinux.org/RPi_config.txt
core_freq=250
sdram_freq=450
over_voltage=6

 

 

 

 

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RPi Keeps Crashing

by on Apr.12, 2014, under Troubleshooting

I have been having issues with the RPi staying online.

My setup is a RPi Model B with a WiFi antanea attached and powered by a 1A wall wort.  There is no keyboard, mouse, or video attached.  All access to the RPi is done over SSH.

The RPi will stay online for aprox. one to three hours then disappear from the network.  Powering off for a hard re-boot would bring it back.  However, one to three hours and we’d have to repeat.  Not acceptable.  Eventually, the constant crashing did corrupt the image on the SD card.

After speaking with some geek friends and consulting Google, I believe the issue is the WiFi adpater.  I believe the WiFi adapter is drawing just enough off the USB to cause power related stability issues.

For now, I have disconnected the WiFi and attached the RPi directly to the network via RJ-45.  After flashing an SD card with a new Raspbian image, the RPi is up and has beed stable for the best part of 24 hours.

When I get ready to do some more testing, I’m going to attach the WiFi via an external, powered USB hub.  This should allow the WiFi adapter to draw sufficient power without having to depend on the RPi for its power source.

More to come…

 

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