Difference between revisions of "Rtc"
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First, the i2c-bcm2708 i2c driver needs to be loaded. As far as I know, in the first few months of the raspberry pi being available, the module was blacklisted and didn't load automatically, but nowadays the module is loaded by default. If it isn't on your system: |
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sudo modprobe i2c-bcm2708 |
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Load the I2C and RTC drivers as root: |
Load the I2C and RTC drivers as root: |
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sudo -s |
sudo -s |
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Revision as of 10:13, 9 January 2015
First, the i2c-bcm2708 i2c driver needs to be loaded. As far as I know, in the first few months of the raspberry pi being available, the module was blacklisted and didn't load automatically, but nowadays the module is loaded by default. If it isn't on your system:
sudo modprobe i2c-bcm2708
Load the I2C and RTC drivers as root:
sudo -s modprobe i2c-dev modprobe i2c:mcp7941x echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-0/device/new_device # For rev1 RPi echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device # For rev2 RPi
To write the system time to the RTC (you might need to run this command twice, when you use the RTC for the first time):
hwclock -w
Read out the RTC, and print the date and time to your console:
hwclock
Read out the RTC, and adjust system time:
hwclock -s
To automatically do this on startup, add the following lines to /etc/rc.d/rc.local
modprobe i2c-dev modprobe i2c:mcp7941x echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-0/device/new_device # For rev1 RPi echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device # For rev2 RPi hwclock -s