The Raspberry Pi Foundation announced today the launch of the official Raspberry Pi 7″ Touchscreen Display. It is the first, and only, display to use the DSI (Display Serial Interface) port on the Raspberry Pi.
The display is on sale right now at a very attractive price: It’s only $60, or roughly £48 in the UK.
Here are a few key specs and features:
- Uses the Display Serial Interface (DSI) connector.
- It’s powered via 5V & GND off GPIO
- The touchscreen display can run simultaneously with an HDMI monitor
- The display is not a HAT (Hardware Attached on Top)
- It’s very easy to wire and set up
- Connection method to Pi leaves all the GPIO exposed for other custom uses
- Screen dimensions: 194mm×110mm×20mm (including standoffs)
- Viewable screen size: 155mm×86mm
- Screen resolution 800×480 pixels
- 10-finger capacitive touch
Background
The new display comes out after years of speculation regarding when or if an official DSI-based screen would come out. Until now, nobody except the Pi Foundation could release a DSI-based screen, since developing the firmware to use the DSI connector pins on the Pi’s GPU (Graphics Processing Unit) required access to closed-source, low-level code and documentation that wasn’t part of the standard Pi open-source offerings; the GPU was and is a closed Broadcom unit.
In technical jargon, such closed firmware is called a binary blob. And as is clear from the lack of DSI-based screens for the Pi, binary blobs completely restrict community based development and hamper 3rd-party innovation. Unfortunately, binary blobs are fairly common for embedded dev. boards to have and though it’s no real fault of the Foundation, the Pi user community has experienced the annoyances of these blobs since the Pi came out in 2012.
But other manufacturers have tried to satisfy the community’s desire for a Raspberry Pi compatible display. Without access to the low-level GPU timing and instructions, though, designers have been forced to develop products that used either HDMI-based monitor panels or that were driven off of GPIO connector, a suboptimal configuration. With a DSI based solution, no GPIO are taken up and only three wires are required to connect between the Pi and the display adapter — the DSI ribbon cable (with 15 wires, though not GPIO), and two jumper wires for power and ground.
And it’s about time for the Pi Foundation to light up the DSI — not just for its fans, but also for its pocketbook. Talking with Tech Crunch in October 2014, Eben Upton, founder and CEO of the Raspberry Pi Foundation, estimated that putting the DSI on each Pi board cost the Foundation upwards of £400,000 — roughly $608,000. That’s a lot of money to spend on a useless socket.
Kit Contents
So the long-awaited, well-priced, DSI-based Raspberry Pi Display solves several problems. And it’s a fairly complete solution. The kit includes more than just the display:
- The 7″ touchscreen
- Adapter board
- DSI ribbon cable
- 4 stand-offs and screws
- 4 jumper wires
In other words, it comes with everything you need to get the display working, except for the the Raspberry Pi and wall wart. (In hands-on testing, the Foundation’s power supply, rated at 5V 2A, drove the Raspberry Pi 2 Model B, Wi-Fi adapter, RF keyboard dongle, and the screen without any glitches.)
Hands-on
Before physically installing the screen on your Raspberry Pi, you need to update the firmware. With the Pi hooked up to a monitor and keyboard, boot up the board, log into the system, and once you have a command prompt, type sudo apt-get update, and then sudo apt-get upgrade.
The first command updates the package list for your operating system and the second command upgrades the system. The latter of the two commands also pulls the firmware drivers necessary for the new display to work. The touchscreen feature of the display should automatically configure by itself, but you’ll find that certain applications such as Minecraft may need tweaks to their keybindings to work in a comfortable manner.
Next, with the Pi powered off, connect the ribbon cable from the Pi DSI connector to the adapter. The DSI connector is labelled Display on the board and closest to the edge of the Pi. The CSI connector is more interior to the board and labelled Camera. Don’t confuse the two as they are different; the display will not work in the camera port and vice versa.
Finally, take two jumper wires from the display kit and wire the 5V pin on the Pi to the 5V pin on the adapter, and the ground pin on the Pi to the ground pin on the adapter (the images above uses the conventional red wire for power and a black for ground).
Mounting holes on the rear of the display accommodate the newer Raspberry Pi boards. You’re out of luck if you’re using the original Model B or A boards, but it’s quite likely that an industrious Pi fan will render and 3D print an adapter plate. (If you do, by all means let us know about it in the comments below!)
Taking it to the Next Level
For those looking to do more with the screen than game or build a thick Pi-based tablet, check out Kivy. The Python based user interface framework is quick to deploy and quite powerful. For more on Kivy, check out Matt Richardson’s video above. And if you’re wondering how he got a display so quickly, it’s because he’s the product evangelist for Raspberry Pi.
Share your ideas and tell us what you’ll make with the new screen in the comments below. Who knows, we might just like your idea enough to run it in the magazine.
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