The Raspberry Pi Foundation released a new Raspbian SD card image yesterday with some interesting new features including dynamic overclocking. I had the July Raspbian image on an SD card which I already setup with everything I need to do a demo, so I didn't really want to have to startover with a fresh image. Therefore, I decided to give the upgrade process a try:
UPDATE: If you just want overclocking and not a full update of all packages, then asb suggests just doingsudo apt-get update && sudo apt-get install raspberrypi* raspi-config
1) From LXTerminal, I was able to upgrade the installed software packages via:
sudo apt-get update
sudo apt-get upgrade
You'll need to be connected to the Internet and beware that the second command, upgrade, took well over a hour to complete.
2) The next step is to upgrade the firmware by using the rpi-update utility. I didn't already have this utility, so I downloaded it via the instructions on the GitHub:
I was pleseantly suprised to see it's now a Linux 3.2 kernel instead of 3.1 as it previously had been.
5) I was eager to give the overclocking a spin. The CPU frequency is dynamically overclocked when the system activity warrants it (and internal chip temperature is low enough to be safe). In order to tell when the overclocking was happening, I wrote quick loop in the shell to log the current CPU frequency every 5 seconds:
And then I played Quake for a bit. Sure enough, this triggered the Pi to kick up to 1GHz for a period of time as my log revealed:
I also observed that the CPU would increase to 1GHz often when using the Midori web browser, too.