启用树莓派SPI与I2C：config.txt配置详解

################################################################################
##  Raspberry Pi Configuration Settings
##
##  Revision 16, 2013/06/22
##
##  Details taken from the eLinux wiki
##  For up-to-date information please refer to wiki page.
##
##  Wiki Location : http://elinux.org/RPiconfig
##
##  For more options and information see
##  http://www.raspberrypi.org/documentation/configuration/config-txt.md
##  Some settings may impact device functionality. See link above for details
##
##  Description:
##    Details of each setting are described with each section that begins with
##    a double hashed comment ('##')
##    It is up to the user to remove the single hashed comment ('#') from each
##    option they want to enable, and to set the specific value of that option.
##
##  Overclock settings will be disabled at runtime if the SoC reaches temp_limit
##
################################################################################

################################################################################
##  Standard Definition Video Settings
################################################################################

## sdtv_mode
##     defines the TV standard for composite output

##
##     Value    Description
##     -------------------------------------------------------------------------
##     0        Normal NTSC (Default)
##     1        Japanese version of NTSC - no pedestal
##     2        Normal PAL
##     3        Brazilian version of PAL - 525/60 rather than 625/50, different
##              subcarrier
##
#sdtv_mode=0

## sdtv_aspect
##     defines the aspect ratio for composite output
##
##     Value    Description
##     -------------------------------------------------------------------------
##     1        4:3 (Default)
##     2        14:9
##     3        16:9
##
#sdtv_aspect=1

## sdtv_disable_colourburst
##     Disables colour burst on composite output. The picture will be
##     monochrome, but possibly sharper
##
##     Value    Description
##     -------------------------------------------------------------------------
##     0        Colour burst is enabled (Default)
##     1        Colour burst is disabled