MCIMX286CVM4B Freescale Semiconductor, MCIMX286CVM4B Datasheet - Page 2127

• Manufacturer Part Number: MCIMX286CVM4B
• Description: IC MPU I.MX286 289MAPBGA
• Manufacturer: Freescale Semiconductor
• Series: i.MX28r

Specifications of MCIMX286CVM4B

• Core Processor: ARM9
• Core Size: 32-Bit
• Speed: 454MHz
• Connectivity: CAN, EBI/EMI, Ethernet, I²C, MMC, SmartCard, SPI, SSI, UART/USART, USB OTG
• Peripherals: DMA, I²S, LCD, POR, PWM, WDT
• Program Memory Size: 128KB (32K x 32)
• Program Memory Type: Mask ROM
• Ram Size: 32K x 32
• Voltage - Supply (vcc/vdd): 1.25 V ~ 5.25 V
• Data Converters: A/D 17x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 289-LFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -
• Eeprom Size: -
• Lead Free Status / Rohs Status: Compliant

An overlay can be enabled by writing the address of the overlay image to the OLn register,
the overlay's size and location information into the OLnSIZE register, and then setting the
OLnPARAM_ENABLE bit. The OLnPARAM registers also contain further controls to
select the modes of operation (below).
34.2.6 Alpha Blending
The alpha value for an individual pixel represents a mathematical weighting factor applied
to the S1 pixel. An alpha value of 0x00 corresponds to a transparent pixel and a value of
0xFF corresponds to an opaque pixel.
The effective alpha value for an overlay pixel is determined by the ALPHA bit-field and
the two ALPHA control bits in the OLnPARAM register. If the ALPHA_CTRL field is set
to ALPHA_OVERRIDE, the alpha value for the pixel is taken from the ALPHA bit-field.
This can be useful for applying a constant alpha to an entire image or for image formats
that do not include an alpha value. If ALPHA_MULTIPLY is selected, the pixel's alpha
value will be multiplied by the ALPHA value in order to allow scaling of the pixel's alpha
or to provide better control for pixel formats such as RGB1555, which only contains a single
bit of alpha.
For each color channel, the equation used to blend two source pixels is defined below:
The result for the red channel as an example is as follows:
When alpha is 0xFF, the S1 pixel will not be blended with S0, but S1 will be passed as the
output pixel and will not be blended with S0. In this case, S0 will be discarded. Likewise,
if alpha is 0x00 for a given pixel, S0 will be loaded as the output pixel.
Alpha values in the overlays are loaded from the source image for all pixel formats. For
formats that do not support an alpha value, the pixel is assigned an alpha value of 0xFF
(opaque). This can be modified by the overlay processing by setting either the
ALPHA_MULTIPLY or ALPHA_OVERRIDE bit in the associated OLnPARAM register.
Freescale Semiconductor, Inc.
E = Embedded alpha associated with S1 pixel
G = PIO programmed global alpha (8-bit value)
Yr[7:0] = ( * S1.r) + ((1 - ) * S0.r)
= G * E + 0x80
i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
Chapter 34 Pixel Pipeline (PXP)
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