NXP Semiconductors MPC5606S - Graphics and Data Format

Display Control Unit (DCU)
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor 411
If the WIDTH bit field is set to an invalid multiple, then the layer configuration is invalid, the layer cannot
be made visible, and an error flag is set in the layer parameter error register (PARR_ERR).
The position of each layer on the panel is defined by register 2 in the control descriptor for the layer
(CTRLDESCLn_2, where n is the layer number). The register contains two bit fields, POSY and POSX,
which determine the location of the upper left pixel of the layer in the x and y axes. Both fields are
expressed in terms of the number of pixels in each axis.
There are no restrictions on layer placement. Any layer can be placed and moved to any panel position. If
a layer is placed so that pixels would appear beyond the dimensions of the panel, then the DCU displays
the pixels on the panel and ignores the pixels off the panel.
12.4.5.4 Graphics and data format
The memory location of the graphic that is displayed on the layer is defined by register 3 in the control
descriptor for the layer (CTRLDESCLn_3, where n is the layer number). This 32-bit value can contain the
address of any memory location in the memory map of the MCU.
The format of the data that describes the graphic is defined by the BPP bit field in register 4 in the control
descriptor for the layer (CTRLDESCLn_4, where n is the layer number). This value also influences the
range of values for the width of the layer (see Section 12.4.5.3, Layer size and positioning). By choosing
an appropriate format, it is possible to optimize the memory required by the graphics in use.
There are five formats where the RGB values of the pixels are stored directly in the graphic. In these
formats, the DCU treats the data as describing a true RGB color. The formats are:
• ARGB8888, where the data defines 8-bit values for the red, green, blue, and alpha components of
the image.
• RGB888, where the data defines 8-bit values for the red, green, and blue components of the image.
• RGB565 where the data defines 5-bit values for the red and blue components, and 6-bit values for
the green component of the image.
• ARGB1555 where the data defines 5-bit values for the red, green, and blue components, and a 1-bit
value for the alpha channel of the image.
• ARGB4444, where the data defines 4-bit values for the red, green, blue, and alpha components of
the image.
Table 12-52. Example of WIDTH multiples for different graphic data formats
Data format WIDTH multiples Example values
1 bpp 16 16, 32, 48, 64, …
2 bpp 16 16, 32, 48, 64, …
4 bpp 8 8, 16, 24, 32, …
8 bpp 4 4, 8, 12, 16, …
16 bpp 2 2, 4, 6, 8, …
24 bpp 4 (= 3 whole 32-bit words) 4, 8, 12, 16
32 bpp 1 1, 2, 3, 4, …