Sony DFW-X700, DFW-SX900 technical manual Command Setting and Operation Timing

DFW-SX900

DFW-X700

COMMAND SETTING AND OPERATION TIMING

The DFW-SX900/X700 operates synchronously with internal pulses called VD. VDs are reference signals inside the camera and cannot be observed from outside the camera.

Even if commands are set to the CSR of the camera, it does not mean that they become effective the instant they have been written. They become effective after the VD period set to the CSR has been completed and the next VD pulse is generated as shown in the following figure. The command settings are set for video signals by the Isochronous output after that. (The timing at which the command settings become effective may delay according to the internal state of the camera.)

When operating at a low frame rate even if the transmission time of one frame exceeds one VD, and the CSR settings are changed during transmission, the command settings will not be set to the video signals until the frame currently being output is complete.

		Setting becomes effective in
Set command to CSR in this period		next VD period (or the next)
VD
	1 V
		Command settings are set to isochronous
		output after setting becomes effective
Isochronous

Isochronous

1 V = Approx. 133 ms (DFW-SX900)	When low frame rate is selected, command
Approx. 67 ms (DFW-X700)
	settings are set to isochronous output after
	completion of isochronous output before setting

Isochronous Transmission Start/Stop command and actual operation timing

As shown in the following figure, it takes at least about 1 V for the actual isochronous transmission of image data to start or stop after the Isochronous Start/Stop command (CSR F0F00614h: ISO_EN) has been set to the CSR of the camera. (VDs are the reference signals inside the camera and cannot be observed from outside the camera.)

Isochronous transmission start/stop is executed in units of frames. Isochronous transmission will not start/stop before one image output ends. This means that if a low frame rate at which the transmission of one image takes a long time is selected, the time taken for executing Isochronous Stop will be long.

Set Iso ON/OFF in this period
VD	1 V
				Approx. 8.0 ms (DFW-SX900)
				Approx. 2.4 ms (DFW-X700)
Isochronous
			ON		ON/OFF is executed with an
					interval of 1 V from V period set
Isochronous		OFF				OFF

Low Frame Rate

7.5Frame/s (DFW-SX900) 15 Frame/s (DFW-X700)

If Shutter (CSR F0F0081Ch) is set to the extended exposing mode, command execution may delay for the exposure time at maximum in addition to the previous delay for both Isochronous Start/Stop.

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