MT9P401I12STC Aptina LLC, MT9P401I12STC Datasheet - Page 44

• Manufacturer Part Number: MT9P401I12STC
• Description: SENSOR IMAGE CMOS 5MP 48LCC
• Manufacturer: Aptina LLC
• Type: CMOS Imagingr
• Series: DigitalClarity®r

Specifications of MT9P401I12STC

• Pixel Size: 2.2µm x 2.2µm
• Active Pixel Array: 2592H x 1944V
• Frames Per Second: 60
• Voltage - Supply: 2.6 V ~ 3.1 V
• Package / Case: 48-iLCC
• Sensor Image Color Type: Monochrome
• Sensor Image Size: 2592x1944Pixels
• Operating Supply Voltage (typ): 1.8/2.8V
• Operating Supply Voltage (max): 3.1V
• Operating Temp Range: -30C to 70C
• Package Type: ILCC
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 48
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 557-1263; MT9P401I12STC; Q3412742

Maintaining a Constant Frame Rate
Synchronizing Register Writes to Frame Boundaries
PDF: 09005aef82acb06f/Source: 09005aef81a4a477
MT9P401_DS_2 - Rev. B 9/07 EN
Maintaining a constant frame rate while continuing to have the ability to adjust certain
parameters is the desired scenario. This is not always possible, however, because
register updates are synchronized to the read pointer, and the shutter pointer for a
frame is usually active during the readout of the previous frame. Therefore, any register
changes that could affect the row time or the set of rows sampled causes the shutter
pointer to start over at the beginning of the next frame.
By default, the following register fields cause a "bubble" in the output rate (that is, the
vertical blank increases for one frame) if they are written in continuous mode, even if the
new value would not change the resulting frame rate:
• Row_Start
• Row_Size
• Column_Size
• Horizontal_Blank
• Vertical_Blank
• Shutter_Delay
• Mirror_Row
• Row_Bin
• Row_Skip
• Column_Skip
The size of this bubble is (SW ×
settings.
The Shutter_Width_Lower and Shutter_Width_Upper fields may be written without
causing a bubble in the output rate under certain circumstances. Because the shutter
sequence for the next frame often is active during the output of the current frame, this
would not be possible without special provisions in the hardware. Writes to these regis-
ters take effect two frames after the frame they are written, which allows the shutter
width to increase without interrupting the output or producing a corrupt frame (as long
as the change in shutter width does not affect the frame time).
Changes to most register fields that affect the size or brightness of an image take effect
on the frame after the one during which they are written. These fields are noted as
“synchronized to frame boundaries” in Table 12: Register List and Default Values on
page 20. To ensure that a register update takes effect on the next frame, the write opera-
tion must be completed after the leading edge of FV and before the trailing edge of FV.
As a special case, in Snapshot modes (see “Operating Modes” on page 47), register writes
that occur after FV but before the next trigger will take effect immediately on the next
frame, as if there had been a Restart. However, if the trigger for the next frame in ERS
Snapshot mode occurs during FV, register writes take effect as with continuous mode.
Additional control over the timing of register updates can be achieved by using
synchronize_changes. If this bit is set, writes to certain register fields that affect the
brightness of the output image do not take effect immediately. Instead, the new value is
remembered internally. When synchronize_changes is cleared, all the updates simulta-
neously take effect on the next frame (as if they had all been written the instant
synchronize_changes was cleared). Register fields affected by this bit are identified in
Table 13: Register Description on page 25.
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MT9P401: 1/2.5-Inch 5Mp Digital Image Sensor
44
t
ROW), calculating the row time according to the new
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