Documentation/video4linux/cpia2_overview.txt - kernel/common - Git at Google

 			Programmer's View of Cpia2

 Cpia2 is the second generation video coprocessor from VLSI Vision Ltd (now a
 division of ST Microelectronics).  There are two versions.  The first is the
 STV0672, which is capable of up to 30 frames per second (fps) in frame sizes
 up to CIF, and 15 fps for VGA frames.  The STV0676 is an improved version,
 which can handle up to 30 fps VGA.  Both coprocessors can be attached to two
 CMOS sensors - the vvl6410 CIF sensor and the vvl6500 VGA sensor.  These will
 be referred to as the 410 and the 500 sensors, or the CIF and VGA sensors.

 The two chipsets operate almost identically.  The core is an 8051 processor,
 running two different versions of firmware.  The 672 runs the VP4 video
 processor code, the 676 runs VP5.  There are a few differences in register
 mappings for the two chips.  In these cases, the symbols defined in the
 header files are marked with VP4 or VP5 as part of the symbol name.

 The cameras appear externally as three sets of registers. Setting register
 values is the only way to control the camera.  Some settings are
 interdependant, such as the sequence required to power up the camera. I will
 try to make note of all of these cases.

 The register sets are called blocks.  Block 0 is the system block.  This
 section is always powered on when the camera is plugged in.  It contains
 registers that control housekeeping functions such as powering up the video
 processor.  The video processor is the VP block.  These registers control
 how the video from the sensor is processed.  Examples are timing registers,
 user mode (vga, qvga), scaling, cropping, framerates, and so on.  The last
 block is the video compressor (VC).  The video stream sent from the camera is
 compressed as Motion JPEG (JPEGA).  The VC controls all of the compression
 parameters.  Looking at the file cpia2_registers.h, you can get a full view
 of these registers and the possible values for most of them.

 One or more registers can be set or read by sending a usb control message to
 the camera.  There are three modes for this.  Block mode requests a number
 of contiguous registers.  Random mode reads or writes random registers with
 a tuple structure containing address/value pairs.  The repeat mode is only
 used by VP4 to load a firmware patch.  It contains a starting address and
 a sequence of bytes to be written into a gpio port.
	Programmer's View of Cpia2

	Cpia2 is the second generation video coprocessor from VLSI Vision Ltd (now a
	division of ST Microelectronics). There are two versions. The first is the
	STV0672, which is capable of up to 30 frames per second (fps) in frame sizes
	up to CIF, and 15 fps for VGA frames. The STV0676 is an improved version,
	which can handle up to 30 fps VGA. Both coprocessors can be attached to two
	CMOS sensors - the vvl6410 CIF sensor and the vvl6500 VGA sensor. These will
	be referred to as the 410 and the 500 sensors, or the CIF and VGA sensors.

	The two chipsets operate almost identically. The core is an 8051 processor,
	running two different versions of firmware. The 672 runs the VP4 video
	processor code, the 676 runs VP5. There are a few differences in register
	mappings for the two chips. In these cases, the symbols defined in the
	header files are marked with VP4 or VP5 as part of the symbol name.

	The cameras appear externally as three sets of registers. Setting register
	values is the only way to control the camera. Some settings are
	interdependant, such as the sequence required to power up the camera. I will
	try to make note of all of these cases.

	The register sets are called blocks. Block 0 is the system block. This
	section is always powered on when the camera is plugged in. It contains
	registers that control housekeeping functions such as powering up the video
	processor. The video processor is the VP block. These registers control
	how the video from the sensor is processed. Examples are timing registers,
	user mode (vga, qvga), scaling, cropping, framerates, and so on. The last
	block is the video compressor (VC). The video stream sent from the camera is
	compressed as Motion JPEG (JPEGA). The VC controls all of the compression
	parameters. Looking at the file cpia2_registers.h, you can get a full view
	of these registers and the possible values for most of them.

	One or more registers can be set or read by sending a usb control message to
	the camera. There are three modes for this. Block mode requests a number
	of contiguous registers. Random mode reads or writes random registers with
	a tuple structure containing address/value pairs. The repeat mode is only
	used by VP4 to load a firmware patch. It contains a starting address and
	a sequence of bytes to be written into a gpio port.