AN2676 Freescale Semiconductor / Motorola, AN2676 Datasheet - Page 10

• Manufacturer Part Number: AN2676
• Description: Image Capture with i.MX21
• Manufacturer: Freescale Semiconductor / Motorola

Software Design
Path 1 (Blue)—A smart sensor with YUV422 / RGB565 output is used. Data is resized and converted to
YUV420 by PRP channel 2 for MPEG4 encoding. The same image is resized and converted to RGB565
color by PRP channel 1 for display on an LCD or SLCD.
Path 2 (Red)—A dumb sensor with Bayer output and a smart sensor with YUV444 / RGB888 output fall
into this category. Data is passed to a software routine for color processing and color conversion to
generate RGB565 output. It is then fed back to the PRP. YUV420 output of full size is produced by PRP
channel 2 for MPEG4 encoding. RGB565, sub-sampled version, is produced by PRP channel 1 for view
finding on LCD or SLCD.
8 Software Design
8.1 CSI with DMA
Data is transferred by DMA from CSI FIFO to main memory. DMA can be configured to run in repeat
mode or non-repeat mode. When DMA is used, CSI FIFO-full interrupts should be disabled.
Figure 9 on page 11 provides an example of pseudocode for DMA non-repeat mode.
10
CSI
Camera
Control
STAT FIFO
Freescale Semiconductor, Inc.
For More Information On This Product,
Statistics
Buffer
Line
YUV422
MC9328MX21 Application Note
RGB565
Go to: www.freescale.com
YUV444
RGB888
Figure 8. Video Record
Bayer
Frame
Buffer
Color
PRP
Proc
RGB565
RGB565
YUV420
Frame
Buffer
Frame
Buffer
Memory
MX21 Module
Software
MPEG4
Encoder
SLCDC
LCDC
MOTOROLA