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Getting Started With Linux on the LPC3250 OEM Board Page 34
Copyright 2009 © Embedded Artists AB Rev A
3. The LTIB configuration menu will appear, see Figure 10. Go to the “Package List” option and
hit the Enter key (or click Select button).
4. You will now see a long list of packages. Scroll down to the option called fbv and press
Spacebar on your keyboard to select the package.
5. Click the Exit button.
6. Click the Exit button.
7. Select “Yes” when asked to save the configuration.
8. LTIB will now compile the selected package and copy it (the application) to the root file
system.
9. Copy a picture to the root file system. Here we assume that you have an image named
pic.png
in your home folder (
/home/user/pic.png
).
$ sudo cp /home/user/pic.png /home/user/ltib/rootfs/home/user
10. If you have an NFS mounted root file system the
fbv
application and picture will be
accessible from your Linux system.
11. Before displaying the image on the screen, make sure the display is enabled. It might have
been disabled for power save reasons.
# echo 0 > /sys/class/graphics/fb0/blank
12. Display the image on the LCD screen.
# fbv /home/user/pic.png
5.3 Touch Screen
5.3.1 Hardware
The touch screen controller mounted on the QVGA Base Board is a Texas Instruments TSC2046
which is a next-generation version to the ADS7846 controller. The TSC2046 is compatible with the
ADS7846.
The TSC2046 controller is a low-voltage controller connected to the SPI bus with low power
consumption and high speed (up to 125 kHz).
There is an embedded touch screen controller on the LPC3250 microcontroller, but that isn’t used with
the Embedded Artists LPC3250 OEM Board.
5.3.2 Device Driver and Configuration
A driver for the ADS7846 is integrated in the kernel and located here in the source tree:
/drivers/input/touchscreen/ads7846.c
.
The following configuration options are related to the touch screen functionality.
Configuration
CONFIG_INPUT_TOUCHSCREEN Enable touch screen support
CONFIG_TOUCHSCREEN_ADS7846
Enable the ADS7846/TSC2046 driver