BELK-AN-004: Interfacing BoraEVB/BoraXEVB to TFT LCD display

History

Version	Date	BELK version	Notes
1.0.0		2.2.0	First release

Introduction

This application note describes the interfacing of Ampire AM-800480STMQW-TA1 display to BoraEVB. This project is based on BELK 2.2.0.

Physical interfacing

To interface the display a small adapter board is needed. It interfaces J22 connector on BoraEVB side and provides a 20-pin connector to directly attach display cable. It is also equipped with a linear regulator generating 2.5V. This voltage is used as power supply for the VDDIO_BANK13 rail. This voltage is required to implement LVDS differential pairs that drive display.

At this URL TBD schematics are available for download.

Block diagram and Vivado design

The following picture shows simplified block diagram of the design.

TBD

LCD is driven by a controller implemented in PL that fetches pixel data from frame buffer and periodically refreshes physical screen. LCD controller provides configuration registers that are mapped in the following address range: TBD

To implement frame buffer, a portion of main SDRAM is used. This area is allocated at runtime by linux frame buffer driver.

At the following URL the Vivado design is available for download: TBD.

Enabling frame buffer driver in linux kernel

To enable frame buffer driver TBD

During kernel bootstrap, the following messages are printed out on console, indicating framebuffer driver has been loaded succesfully:

TBD

Once the kernel has completed boot, frame buffer can be accessed from user space applications via /dev/fb0 device file (for more details please refer to https://www.kernel.org/doc/Documentation/fb/framebuffer.txt).

The following image shows Qt 4.??? demo application running on top of it. TBD