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  • Display Drivers

    This describes the display-driver of the XScale-based Trizeps-modules. The parameters for the display are read in this order ( parameters read later overwrite earlier values):

    1. BootBitmap

    2. [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    3. If a BootBitmap has not been loaded, [HKEY_LOCAL_MACHINE\Drivers\Display\Default\displayname]; where displayname is defined with [HKEY_LOCAL_MACHINE\Drivers\Display\Default] Name.

    The registry-settings are found in the display.reg.

    Registry-Key may vary depending on Trizeps-module and OS-version!

    Registry Keys

    Common to all Trizeps-Modules

    [HKEY_LOCAL_MACHINE\Drivers\Display\Booted Display]

    [HKEY_LOCAL_MACHINE\Drivers\Display\Booted Display]

    Key

    Type

    Description

    Name

    STRING

    Key holding the actual booted display (not the one to be booted!).

    [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    [HKEY_LOCAL_MACHINE\Drivers\Display\displayname]

    Key

    Type

    Description

    Name

    STRING

    Defines the name of the display, which parameters are to be used (Only in \Default).

    DisableBootPars

    DWORD

    If set to 1, ignore the BitmapBoot-parameters.

    CxScreen

    DWORD

    Horizontal-resolution.

    CyScreen

    DWORD

    Vertical-resolution.

    Feature

    DWORD

    Feature-Parameters; i.e. which GPIO to use as PWM, see: BitmapBoot Tool ( Trizeps II - V)

    DisplayOn

    DWORD

    GPIO which turns the display on/off.

    DisplayOnPol

    DWORD

    Polarity of DisplayOn-GPIO.

    BufferStrength

    DWORD

    BufferStrength of the display-lines (PXA270: 0..15; PXA320: 1..7; PXA168:0..3).

    Angle

    DWORD

    Angle ( 0, 90, 180, 270) with which the display starts.

    Angle2

    DWORD

    Alternative Angle (0, 90, 180, 270) used by RotateScreen-applet.

    Trizeps 2,3,4 and 5

    [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    [HKEY_LOCAL_MACHINE\Drivers\Display\displayname]

    Key

    Type

    Description

    Name

    STRING

    Defines the name of the display, which parameters are to be used (Only in \Default).

    Bpp

    DWORD

    Color-depth ( 4, 8, 16).

    Control0 - Control3

    DWORD

    Contain display parameters. See Intel/Marvell PXAxxx Developers Manual.

    EraseFrameBufferOnStart

    DWORD

    If set to 1, clear the framebuffer on start (black screen).

    SuspendColor

    DWORD

    Clear the framebuffer with this color, before going into suspend.

    UseInternalSRAM

    DWORD

    If set to 1 uses internal SRAM for framebuffer. If framebuffer is to big, this could split the framebuffer (internal SRAM and SDRAM). This might be a problem for application that directly access the framebuffer, i.e. DirectDraw.

    DisableOutput

    DWORD

    Disables output of display signals.

    Trizeps 6

    [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    [HKEY_LOCAL_MACHINE\Drivers\Display\Default]

    [HKEY_LOCAL_MACHINE\Drivers\Display\displayname]

    Key

    Type

    Description

    Bpp

    DWORD

    Valid values: 12,16,18,24. Selects number of display-lines to use.

    BaseFramePixelFormat

    DWORD

    Selects Pixel-Format used for framebuffer: 4: RGB565 (16Bpp) 8: RGB8880 (24Bpp)

    ClockDivider

    DWORD

    See Marvell PXA168 Developers Manual. Typical this is set to (0x80000000 | divider); where divider = 312MHz / PCLK-frequency.

    HBackPorch

    DWORD

    Horizontal Back-Porch in Pixel-Clks

    HFrontPorch

    DWORD

    Horizontal Front-Porch in Pixel-Clks

    HSyncWidth

    DWORD

    Horizontal Sync-Width in Pixel-Clks

    VBackPorch

    DWORD

    Vertical Back-Porch in Line-Clks

    VFrontPorch

    DWORD

    Vertical Front-Porch in Line-Clks

    VSyncWidth

    DWORD

    Vertical Sync-Width in Line-Clks

    SyncPolarity

    DWORD

    See Also

    BitmapBoot Tool ( Trizeps II - V),
    Connect a Display to a Trizeps,
    Connect a LVDS Display to a Trizeps