Datasheet

951
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
44. Image Sensor Interface (ISI)
44.1 Description
The Image Sensor Interface (ISI) connects a CMOS-type image sensor to the processor and provides image capture in
various formats. It does data conversion, if necessary, before the storage in memory through DMA.
The ISI supports color CMOS image sensor and grayscale image sensors with a reduced set of functionalities.
In grayscale mode, the data stream is stored in memory without any processing and so is not compatible with the LCD
controller.
Internal FIFOs on the preview and codec paths are used to store the incoming data. The RGB output on the preview path
is compatible with the LCD controller. This module outputs the data in RGB format (LCD compatible) and has scaling
capabilities to make it compliant to the LCD display resolution (See Table 44-3 on page 955).
Several input formats such as preprocessed RGB or YCbCr are supported through the data bus interface.
It supports two modes of synchronization:
1. The hardware with ISI_VSYNC and ISI_HSYNC signals
2. The International Telecommunication Union Recommendation ITU-R BT.656-4 Start-of-Active-Video (SAV) and
End-of-Active-Video (EAV) synchronization sequence.
Using EAV/SAV for synchronization reduces the pin count (ISI_VSYNC, ISI_HSYNC not used). The polarity of the
synchronization pulse is programmable to comply with the sensor signals.
Figure 44-1. ISI Connection Example
Table 44-1. I/O Description
Signal Dir Description
ISI_VSYNC IN Vertical Synchronization
ISI_HSYNC IN Horizontal Synchronization
ISI_DATA[11..0] IN Sensor Pixel Data
ISI_MCK OUT Master Clock Provided to the Image Sensor
ISI_PCK IN Pixel Clock Provided by the Image Sensor
Image Sensor Image Sensor Interface
data[11..0]
ISI_DATA[11..0]
CLK
ISI_MCK
PCLK
ISI_PCK
VSYNC
HSYNC
ISI_VSYNC
ISI_HSYNC