RPi Touch 2.8″ TFT Touchscreen Display Setup Instructions
In this tutorial I will guide you through the setup and configuration process of the RPi Touch 2.8″ TFT LCD Shield.
In order to add support for the RPi Touch 2.8″ TFT and touchscreen, Linux Kernel with framebuffer driver is needed. Lucky for you, we have created a custom image based on the official Raspbian so all you have to do is download it and flash it to the SD card. All credit for creating the drivers goes to the extremely talented Notro.
RPi Touch Ready Image
[button link=”https://www.dropbox.com/s/kwz0a1eaqmlqt1j/2014-06-20-wheezy-raspbian-2014-11-13-rpi-touch.zip?dl=0″ style=”download” size=”medium” color=”green” window=”yes”] Download RPi Touch-Ready Raspbian May 20 2014 Image[/button]
All the necessary drivers and modules are preinstalled on this image and are loaded automatically on every boot.
Note that this image may not be the latest version of Raspbian!
Before you start
You will need a Raspberry Pi with network access and at least 4GB SD card. USB keyboard will also be necessary if you are going to do configuration process on the display instead of SSH.
We will do the configuration and setup process over SSH, but it can also easily be done on the display itself.
Download and Install
First download the Raspbian based RPi Touch ready image from the link above. Extract the ZIP archive and save the extracted image file somewhere safe on your hard drive. Then flash the downloaded image on to a freshly formatted SD card. For a guide of how to do this please read this tutorial.
After the image has been flashed you are ready to boot the Pi and carry on with the setup process.
Plug the screen on to the Raspberry Pi GPIO header and fasten it to the Pi with the supplied 8mm standoff and two nylon screws. Insert the freshly prepared SD card and boot up the Pi.
Upon the first boot file system will be expanded to fill all the available space on the SD card and Pi will automatically reboot. Please do not unplug your pi during this process or the SD card might get corrupted!
Once the Pi has rebooted and you can see the login prompt we can carry on.
The I2C bus allows multiple devices to be connected to your Raspberry Pi. Each device has its own unique address, that can usually be set by connecting the pins of the device to either GND or VCC or mixture of both (depending on the device). It is useful to be able to see which devices are connected to your Pi to make sure everything is working correctly. To do this, we will use the i2c-tools utility.
To verify that the RTC and GPIO port expander chips are detected properly issue the following command
sudo i2cdetect -y 1
You should see two devices detected on I2C address 0x20 (GPIO port expander) and 0x68 (RTC).
[box type=”info” border=”full”]
Note that the RTC chip on the address 0x68 will show as UU which means that this address is currently in use by a driver. This is because the RTC driver is loaded on every boot.
RTC Module Setup
RPi Touch display shield features extremely accurate real time clock module, based on the DS3231 temperature compensated RTC chip.
Backup battery holder takes a 12mm coin cell battery such as CR1220 (not included) and using this battery should keep time for approximately 5 years.
[box type=”alert” border=”full”]To make sure that the RPi Touch shield remembers the time after Raspberry Pi is unplugged please install the battery before proceeding.[/box]
Check that the time is correct on the Pi by issuing the date command. If the Raspberry Pi is connected to the Wifi or Ethernet the time should be automatically set to the correct time.
Now lets’s set the correct time on the RTC chip and make the Raspberry Pi synchronise the time from the chip every time it boots.
To set the time on the chip first load the RTC module by issuing the following command
sudo hwclock -w
This will write the system time to the RTC. You can then verify it with sudo hwclock -r
That’s it! From now on every time the Pi boots, time will automatically be synchronised from the RTC.
If you have any comments or suggestions please get in touch.