MT9V012 Micron, MT9V012 Datasheet - Page 13

• Manufacturer Part Number: MT9V012
• Description: 1/6-Inch VGA CMOS Digital Image Sensor
• Manufacturer: Micron

Output Data Format (Serial Mode)
Output Data Timing (Serial Mode)
Figure 10: Start of Frame: Serial Mode
PDF: 814eb99f/Source: 8175e929
MT9V012_2.fm - Rev. B 2/05 EN
Notes: 1. Latency between parallel event and equivalent serial event.
FRAME_VALID
The MT9V012 image data is read out in a progressive scan. In serial mode, valid image
data is surrounded by horizontal blanking and vertical blanking, as shown in Figure 7 on
page 10. However, unlike default mode, serial mode provides pixel data and timing
strobes combined into a single serial bit stream. Electrically, this bit stream uses LVDS
on the D
In serial mode, each pixel is encoded as a 12-bit value by adding a start bit and a stop bit.
The sensor CLKIN input runs at the serial bit-rate and is used within the sensor to clock
a data serializer circuit; it is divided within the sensor so that most of the circuitry runs at
the same rate as in default mode. In serial mode, the pixel rate is fixed at one-half the
input frequency; therefore, CLKIN runs at 6 x 27 MHz = 162 MHz.
The default frame timing in serial mode is identical to the frame timing in default mode.
A special three-character “start-of-frame” sequence—0x3FF, 0x0, and 0x3FF—is trans-
mitted to indicate the assertion of FRAME_VALID. Pixel data, LINE_VALID, and
FRAME_VALID can be reconstructed externally by detecting the start-of-frame
sequence, and using a state machine and counters to identify the active regions of the
frame.
Figure 10 on page 13 shows the beginning of a start-of-frame sequence. It shows the
latency introduced in the parallel-to-serial conversion, and the way in which start and
stop bits are used to frame 10-bit pixel data. Figure 11 on page 14 shows the serial data
stream at the start of a line. In this figure, each 12-bit serial character is represented by
its 10-bit payload. In both figures, the LINE_VALID and FRAME_VALID signals are
shown for reference only; these signals are not available in serial mode.
The most effective method for detecting the start-of-frame sequence is to look for a con-
tinuous sequence of idle (0x0) characters before looking for the 0x3FF, 0x0, 0x3FF
sequence. The start-of-frame sequence indicates the start of a frame without ambiguity,
as it can never occur as part of a pixel data stream.
In addition, correct operation in serial mode requires that various register settings are
left at their default values. For example, Reg0x0A and Reg0x20[15:14].
The sensor timing in serial mode is calculated in exactly the same way as for default
mode. See “Output Data Timing (Default Mode)” on page 11.
2. First character in start-of-frame sequence.
D
CLKIN
D
OUT
OUT
N
P
OUT
Start
Bit
P and D
LSB
(Idle)
0x0
MT9V012 - 1/6-Inch VGA CMOS Digital Image Sensor
OUT
MSB
N output signals.
Stop
13
Bit
Micron Technology, Inc., reserves the right to change products or specifications without notice.
(Idle)
0x0
Output Data Format (Serial Mode)
©2004 Micron Technology, Inc. All rights reserved.
0x3FF
2
Preliminary
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