MT9M019 Aptina Imaging Corporation, MT9M019 Datasheet - Page 37

• Manufacturer Part Number: MT9M019
• Description: 1/5-Inch 1.3Mp CMOS Digital Image Sensor
• Manufacturer: Aptina Imaging Corporation

Gain Code Mapping
PDF: 7723845879/Source:2828556980
MT9D019_DS - Rev. F 5/10 EN
As a result of the 2X gain stage, many of the possible gain settings can be achieved in two
different ways. For example, red_gain = 0x90 provides the same gain as red_gain = 0x20.
The first example uses the 2X gain stage and the second example does not. In all cases,
the preferred setting is the setting that enables the 2X gain stage, since this will result in
lower noise.
The Aptina gain model maps directly to the underlying structure of the gain stages in the
analog signal chain. When the SMIA gain model is used, gain codes are translated into
equivalent settings in the Aptina gain model.
When the SMIA gain model is in use and values have been written to the
analogue_gain_code_<color> registers, the associated value in the Aptina gain model
can be read from the associated <color>_gain register. In cases where there is more than
one possible mapping, the 2X gain stage is enabled, to provide the mapping with the
lowest noise.
When the Aptina gain model is in use and values have been written to the gain_<color>
registers, data read from the associated analogue_gain_code_<color> register is UNDE-
FINED. The reason for this is that many of the gain codes available in the Aptina gain
model have no corresponding value in the SMIA gain model.
The result of this is that the two gain models can be used interchangeably but, having
written gains through one set of registers, those gains should be read back through the
same set of registers.
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MT9M019: 1/5-Inch 1.3Mp CMOS Digital Image Sensor
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