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I'm new to the Raspberry Pi community, but I want to work with the Pi 3 and Android Things.

I want to connect a 7" display via HDMI and USB to my Raspberry Pi 3 (running with Android Things 0.5.1)
Here the link to display: 7" HDMI LCD (C)

I also followed the instruction on the manual and added the lines to the config.txt which is located in the root of my SD card

max_usb_current=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 1024 600 60 6 0 0 0
hdmi_drive=1

Then I plug in the display. It's definitely on! But the display only shows a black screen.

My config.txt

I attached my complete config.txt, maybe I'm missing something. And again: I only added the lines shown above

kernel=u-boot-dtok.bin
framebuffer_depth=16

# Prevent the firmware from loading HAT overlays now that we handle pin muxing.
# ourselves. See:
# https://www.raspberrypi.org/documentation/configuration/device-tree.md#part3.4
dtoverlay=

dtparam=i2c_arm=on
dtparam=spi=on
dtparam=audio=on

# pwm and I2S are mutually-exclusive since they share hardware clocks.
dtoverlay=pwm-2chan-with-clk,pin=18,func=2,pin2=13,func2=4
dtoverlay=generic-i2s

start_x=1

# Tell U-boot to always use the "serial0" interface for the console, which is
# set to whichever uart (uart0 or uart1) is set to the header pins. This doesn't
# interfere with the uart selected for Bluetooth.
dtoverlay=chosen-serial0

# Enable skip-init on the UART interfaces, so U-Boot doesn't attempt to
# re-initialize them.
dtoverlay=rpi-uart-skip-init

# Add pin devices to the system for use by the runtime pin configuration driver.
dtoverlay=runtimepinconfig
dtoverlay=uart1
dtoverlay=bcm2710-rpi-3-b-spi0-pin-reorder

# Tell the I2S driver to use the cprman clock.
dtoverlay=bcm2710-rpi-3-b-i2s-use-cprman

# Uncomment to disable serial port on headers, use GPIO14 and GPIO15
# as gpios and to allow the core_freq to change at runtime.
enable_uart=1
core_freq=400

# Enable hardware graphics acceleration.
dtoverlay=vc4-kms-v3d,cma-256
mask_gpu_interrupt0=0x400
avoid_warnings=2

# Support official RPi display.
dtoverlay=i2c-rtc,ds3231
dtoverlay=rpi-ft5406
hdmi_force_hotplug=1
hdmi_drive=2

# Support custom Waveshare 7inch display
max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 1024 600 60 6 0 0 0
hdmi_drive=1

Contacted the support

I also contacted the manufacturer support, and I received this:

Yes, it can. However, during the test. With only long HDMI cable such as 1m the LCD could display with new version android things. We don't find the reason.

Update - Downgrade to Android Things 0.4.1

I created a new image with Android Thing 0.4.1 and extended the config.txtwith my device specs, and voilá it's working...

But can maybe someone here help me out to get the display running und 0.5.1? Here is my "updated" config.txt

There are some differences between this config and the one I posted above. And of course this config isn't runnable for AT 0.5.1

kernel=u-boot-dtok.bin
framebuffer_depth=16
dtparam=i2c_arm=on
dtparam=spi=on
dtparam=audio=on

# pwm and I2S are mutually-exclusive since they share hardware clocks.  To
# enable I2S comment out the pwm line and uncomment the generic-i2s line.
dtoverlay=pwm-2chan-with-clk,pin=18,func=2,pin2=13,func2=4
# dtoverlay=generic-i2s

start_x=1

# Tell U-boot to always use the "serial0" interface for the console, which is
# set to whichever uart (uart0 or uart1) is set to the header pins. This doesn't
# interfere with the uart selected for Bluetooth.
dtoverlay=chosen-serial0

# Enable skip-init on the UART interfaces, so U-Boot doesn't attempt to
# re-initialize them.
dtoverlay=rpi-uart-skip-init

# Uncomment to disable serial port on headers, use GPIO14 and GPIO15
# as gpios and to allow the core_freq to change at runtime.
enable_uart=1
core_freq=400

max_usb_current=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 1024 600 60 6 0 0 0
hdmi_drive=1
1

I have the SC7B variant of this display (800x480) working with Android Things 0.5.1-dp.

To do this I used the configuration supplied in the documentation (similar to yours) and commented out the RPi official display entries at the end of the file. I also removed the extra hdmi_mode=1 line as it looks like a duplicate line. Here is the changed lines of the configuration I used:

# Support official RPi display.
#dtoverlay=i2c-rtc,ds3231
#dtoverlay=rpi-ft5406
#hdmi_force_hotplug=1
#hdmi_drive=2

# SC7B display
hdmi_force_hotplug=1
max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 800 480 60 6 0 0 0

I did also have to follow the manufacturer suggestion to use a longer cable - the supplied short cable does not work and results in a blank display.

  • And the 7B is, seven beers? Please add references, data and relevant info. – MatsK Oct 4 '17 at 20:33

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