Raspberry Pi A, User Manual, Page: 129 / 314

C H A P T E R 7
A D V A N C E D R A S P B E R R Y P I C O N F I G U R A T I O N
113
❍
hdmi_group —Sets the HDMI group mode to CEA or DMT. You should change this
setting according to the display type you’re trying to connect, before using
hdmi_mode
to control the output resolution and frequency. The two possible values are:
•
1 —Sets the HDMI group to that defined by the Consumer Electronics Association
of America (CEA). Use this setting when the Pi is connected to a high-definition
television (HDTV) over HDMI and use the first settings list from Appendix C,
“HDMI Display Modes”.
•
2 —Sets the HDMI group to that defined by the Video Electronics Standards
Association (VESA) in the Display Monitor Timings (DMT) specification. Use this
setting when the Pi is connected to a computer monitor over DVI and use the
second settings list from Appendix C, “HDMI Display Modes”.
❍
hdmi_safe —Forces the Pi to use a pre-set collection of HDMI settings designed to
provide maximum compatibility with displays connected to the HDMI port. Setting
this to a value of
1
is the equivalent of setting
hdmi_force_hotpug=1
,
config_
hdmi_boost=4
,
hdmi_group=1
,
hdmi_mode=1
and
disable_overscan=0
.
❍
config_hdmi_boost
—Some monitors require more power on the HDMI output to
operate. If your picture looks snowy, try increasing this value in stages from
1
(for
short cables) to
7
(for long cables).
Each option in
config.tx
t should be on its own line, with the option name followed by an
equals sign (
=
) and then the required value. For example, to tell the Pi to use a PAL-format
analogue TV with a 4:3 aspect ratio and a 20-pixel overscan on all sides, put the following
lines into
config.txt
:
sdtv_mode=2
sdtv_aspect=1
overscan_left=20
overscan_right=20
overscan_top=20
overscan_bottom=20
To tell the Pi to use a DVI display through the HDMI port in the 720p60 format with no
overscan at all, use the following values instead:
hdmi_group=1
hdmi_mode=4
hdmi_drive=1
disable_overscan=1