Datasheet

VIPER / VIPER-Lite Embedded Linux Development Kit Quickstart Arcom Embedded Linux (AEL)

Display controller

The display controller driver module (pxafb) is configured by default for a 320x240 TFT

display. The driver module should be loaded using the normal modprobe command:

# modprobe pxafb

This Development Kit is supplied with a VIPER FPIF-CRT interface module. For best

results the display controller can be configured for 640x480-16 VGA mode using:

modprobe pxafb options=mode:640x480-16

Correspondingly

the Screen section from /etc/X11/xorg.conf file needs to be modified to:

Section "Screen"

Identifier "Default Screen"

Device "PXA255 integrated controller"

Monitor "Generic Monitor"

DefaultDepth 16

Subsection "Display"

Depth 16

Modes "640x480" "320x240"

EndSubSection

EndSection

In order to use a flat panel display, extra parameters must be passed to the modprobe

command, either on the command line or using one of the methods described in the

AEL Technical Manual. The options are given as a comma separated list of parameters.

Where a parameter requires a value, it is separated from the parameter name using a

colon. The available parameters are listed in the following table:

The registers referred to are described in section 7.6.4 of the PXA255 Processor

Developer’s Manual, in the /references/ folder on the Development Kit CD.

Parameter Description Default

mode

The required video mode has the following format:

XRESxYRES-BPP

Where XRES is the X-axis resolution, YRES is the

Y-axis resolution and BPP is the desired bit depth.

The hardware supports multiple resolutions (which

include, but are not limited to, 320x240, 640-480

800x600)

and bit depths of 1, 2, 4, 8 and 16 bits. The

LCD

driver is known to work well in 8- or 16-bit mode.

Resolutions above 640x480-16 may cause

video artifacts on your screen image.

The mode parameter corresponds to the

LCCR1[PPL], LCCR2[LPP] and LCCR3[BPP]

registers.

mode:

320x240-16

continued…