BeagleBone Black Gets New Touch Sensing TFT LCDs with I2C

June 08, 2017 by Kate Smith

This News Brief discusses a new TFT LCD released for BeagleBone Black.

This News Brief discusses a new TFT LCD released for the BeagleBone Black.

4D Systems has announced a new series of TFT LCD capes for the BeagleBone Black SBC. TFT (thin-film-transistor) displays are a form of LCD that utilize backlights and electrodes to provide a clearer image than traditional LCDs. 

The gen4 CAPE series consists of six models with either capacitive or resistive touch options. There's also evidently a non-touch version of the displays (utilizing an external button board), but this is only available by request.

Each of the six models comes with a gen4 CAPE adapter board, connected via a 30-pin FPC cable that transfers both data and power.


The 4DCAPE adaptor


Both capacitive and resistive touch models utilize I2C communication, replacing the analog input communication used in previous LCD capes that was more vulnerable to EMI issues.

The TI TPS61165 backlight driver allows the user to adjust screen brightness without using PWM.


The resistive touch (above) and capacitive touch (bottom) capes

Resistive Touch Models

Each of the resistive touch models uses a Microchip AR1021 controller. 

  • gen4-4DCAPE-43T: 4.3-inch
  • gen4-4DCAPE-50T: 5.0-inch
  • gen4-4DCAPE-70T: 7.0 inch

Capacitive Touch Models

The models with capacitive touch functionality also communicate via I2C but use a Focaltech controller instead of a Microchip controller.

  • gen4-4DCAPE-43CT-CLB: 4.3-inch
  • gen4-4DCAPE-50CT-CLB: 5.0-inch
  • gen4-4DCAPE-70CT-CLB: 7.0-inch


Though the series is marketed with the BeagleBone Black in mind, the displays also support the BeagleBone Green and BeagleBone Black Wireless. It's notable, however, that they are not backwards-compatible and cannot be used with the BeagleBone White.

Check out the gen4 CAPE datasheet (PDF) for more information.