HDMI and LCD design

Hello All,

I would like to design/purchase a BBB cape which has LCD and HDMI together.

But one requirement for me is to know if it is possible to have
different video outputs in boths interfaces (for instance, a video
playback on HDMI and an HMI buttons on LCD).

Is it possible to achieve with BBB?

Best regards,


You should be more specific what you are trying to archive. All lcd lines are tied to a hdmi chip therefore if you use them as gpio the hdmi will not function. however both functions can live together, but only one of them is available at a time


I want to be able to manage 2 displays with BBB. Each display will
show differente information.

For instance: a HDMI output playing video and a LCD display with
internet browser. Both applications must be executed by BBB.

Is it possible to do that?

Best regards,


The HDMI output on the BBB uses the LCD interface, so you can't have two
independent displays that way. You can hook up something like the
"smart" displays folks are using on things like the Arduino-based 3D
printer controllers and have a second display that way, but you won't
have access to it via conventional Linux constructs like the frame
buffer interface.

That is impossible. Have you read the System Reference Manual or looked at the schematic? The LCD pins connect to the HDMI chip and the expansion headers. They are the same pins ad can handle data for one display. Not two.


In respects to a monitor, the BBB is like any other computer with onboard video. You need a way to attach the monitor to the PC. The BBB has ONE built in interface for a monitor - the LCD pins. These pins can be connected to either the HDMI port OR they can be connected to an LCD monitor.

Like any other computer, in order to get more monitors than that you will need to install another interface. So you could use a DisplayLink based USB monitor to get a second monitor if you wanted.

Unlike a windows computer, Linux has lots of weird little experimental video drivers made to scratch an itch.

There are at least 3 different SPI display drivers for linux, one of them might work. See https://github.com/notro/fbtft for a working driver using SPI on the Raspberry Pi.

There are at least 2 different GPIO drivers that bit bang the lcd controller. One of them is again, https://github.com/notro/fbtft

There are also a number of “virtual” display drivers that create a virtual screen[but then you need some way of switching to that frame]. For example, if you setup VNC Server on your BBB it can be configured to provide a “virtual” monitor display for remote users. There is probably a way to configure it so you can have multiple monitors over a single remote system as I’m sure someone would have played with that - it just might not be very reliable.

There are also TWO projects primarily focused on providing “auxilary LCD display” capabilities:
LCDProc http://lcdproc.omnipotent.net/

LCD4Linux http://ssl.bulix.org/projects/lcd4linux/

Their primary focus is in using text LCD displays such as those sold by CrystalFontz http://www.crystalfontz.com/ but I have run across hacks/drivers that build off of those projects to use some of the more advanced LCD’s as regular displays.

It all depends on how much “work” you want to put into it. It you want to just do “plug and play” go with a USB Display.

That's what I thought (impossible).

But I had some hope somebody had similar challenge and found an answer.

Thank you very much.

Best regards,


Thank you very much.

Maybe that's the answer that I was looking for.

I'll check it out and give feedback.

Best regards,