PXD10RM Datasheet, PDF (408/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

Pixel Clock = (DCU Clock) / PRESCALE VALUE
where PRESCALE VALUE is an integer value that can range from 2–32.
Eqn. 12-55
12.4.3 DCU Mode selection and background color
Once the DCU is configured for use with a particular TFT LCD panel, it can be enabled for use. There are
five modes to choose from, as shown in Table 12-52.
Table 12-52. List of DCU operating modes
Mode
Off
Color bar
Normal
PDI normal
PDI slave
DCU_MODE[1:0]
00
11
01
01
01
PDI_EN
X
X
0
1
0
Description
DCU disabled; the TFT LCD panel is not driven.
DCU displays a test pattern consisting of vertical bands of programmable
color.
DCU blends layers and displays result on TFT LCD panel.
As normal mode, except that the panel timing is defined by the input on
the PDI interface, and the background color is replaced by the content
provided on the PDI interface.
The DCU synchronizes its timing to an external signal when
PDI_SLAVE_MODE is enabled.
The DCU_MODE, PDI_EN and PDI_SLAVE_MODE control bits are in the DCU_MODE register. The
DCU has an interface enable bit for the TFT LCD panel interface called RASTER_EN, also in the
DCU_MODE register. When RASTER_EN is 0 the raster scanning of pixels to the panel is disabled but
the pixel clock continues to run as long as DCU_MODE is in an active state.
Color bar mode is intended for testing the interface between the DCU and the TFT LCD panel. In this
mode, the panel is divided into eight vertical strips of equal width, and the strips display a single color
whose RGB value is specified in the COLBAR_1 to COLBAR_8 registers. At reset, the colors are set to
black, blue, cyan, green, yellow, red, magenta, and white, where positive logic for the RGB values is
assumed. The mode can be used to verify correct connection of the interface to the DCU and correct timing
configuration of the interface. In this mode, any layer configuration settings are ignored.
In Normal mode, the DCU operates according to the timings specified in Section 12.4.2, TFT LCD panel
configuration” and displays graphics according to the configuration of its layers. The BGND register sets
the RGB color of the background shown when no other layers are present. This background color is
included in the layer blending process but, since it is always the background, it does not include any layer
blending settings.
In PDI normal mode, the DCU adopts the timing provided on the PDI interface and replaces the
background color by the pixel data coming from the PDI interface. The timing values set in the DCU are
ignored in this mode, and the pixel clock and synchronization signals are taken from the PDI interface and
passed to the TFT LCD panel. The content of the panel is a combination of the incoming pixel stream and
layers generated by the DCU.
PDI slave mode allows the DCU to synchronize with the external timing signals on the PDI input.
12-76
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor