User`s manual

Getting Started With Linux on the LPC3250 OEM Board Page 33

5 Peripherals and Drivers

5.1 Introduction

This chapter describes some of the peripherals on the LPC3250 OEM Board, their drivers and how to

use the peripherals from within Linux.

5.2 Display

5.2.1 Hardware

A 3.2 inch QVGA color TFT LCD display is mounted on the QVGA Base Board together with a

Solomon Systech SSD1289 LCD controller. The SSD1289 is attached to the SPI bus. The LPC3250

also has an embedded LCD controller which is compatible with the ARM PrimeCell PL110.

Both the SSD1289 and LPC3250 LCD controllers will be used. The SSD1289 will be used for initial

initialization of the display after a power-cycle of the display.

5.2.2 Device Driver and Configuration

The ARM PrimeCell PL110 device driver contains the majority of the code for the display and is

located here in the source tree:

/drivers/video/amba-clcd.c

The usage of the SSD1289 controller is located in the board specific file:

/arch/mach-

lpc32xx/board-ea3250.c

. More specifically the

clcd_enable

callback will initialize the

display using the SSD1289 controller.

The configuration options below are related to the display functionality.

Configuration

Description

CONFIG_FB Enable frame buffer support

CONFIG_FB_ARMCLCD

Enable the PL110 driver

5.2.3 Usage

The frame buffer is exposed to user space as a device file called

/dev/fb0

. It can be used directly

by an application to output graphics onto the display, for example, by memory mapping the file. A more

common way is to use a graphical API such as Microwindows, DirectFB or SDL instead.

By default, functionality called “console on framebuffer” and “Bootup Logo” has been enabled. This

means that you should see the Linux penguin in the top left corner of the display when you boot the

board.

You can also use the applications described in the touch screen section, see 5.3.3 to see usage of the

display.

5.2.4 Add and Use the fbv Application

The fbv application allows displaying images on a frame buffer. Supported image formats include png,

jpeg and bmp.

1. In your Linux distribution (for example Fedora 11 or Ubuntu 9.04) go to the ltib directory.

$ cd /home/user/ltib

2. Run the ltib script with the configure option.

$ ./ltib --configure