Datasheet

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MT9D111__5_REV5.fm - Rev. B 2/06 EN
85 ©2004 Micron Technology, Inc. All rights reserved.
MT9D111 - 1/3.2-Inch 2-Megapixel SOC Digital Image Sensor
JPEG Indirect Registers
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Auto Focus Mechanics
Table 16: Driver Variables−Auto Focus Mechanics Driver (ID = 6)
Offs Name Type Default
1
RW Description
0 vmt void*
E0AE RW Pointer to the driver’s virtual method table (VMT). The
AFM driver includes a separate set of control methods
for each supported type of auto focus mechanism (see
afm.type below). Each set of methods is assessable via a
separate VMT. Pointing afm.vmt to one of those VMTs
either enables the AF driver to control the
corresponding type of AF mechanism via the GPIO or
takes away the control of the GPIO from the AF driver.
2typeuchar
0 RW Type of auto focus mechanism (lens actuator) used:
0
—none, 1—helimorph, 2—stepper motor, 3—AD5398.
At sequencer initialization, this variable is set to 0 and
the afm.vmt is pointed to the default VMT of the AFM
driver, which makes the GPIO inaccessible to the AF
driver. Enabling the AF driver to control a lens actuator
via the GPIO involves 2 steps. First, afm.type must be set
to t+128, where t is 1, 2 or 3. Second, the sequencer must
be given REFRESH command by setting seq.cmd to 5. The
nonzero 7th bit in afm.type forces the sequencer to call
AFM_Init function upon that command. The function
makes afm.type equal to t and points afm.vmt to the
VMT through which the AFM driver methods for
controlling actuator type t can be called.
3curPosuchar0
RW Current logical position
2
4 prePos uchar 0
RW Previous logical position
5 status uchar
0 RW Lens actuator status:
Bit 0
—0 if all is OK, 1 if the actuator reported an error
Bit 1
—0 if the lens is stationary, 1 if it is moving
Bit 2—0 if last lens movement direction was forward (+),
1 if the direction was backward (-)
Bits [4:3]
—number of current stepper motor position if
afm.type=2; otherwise unused.
After sending a command to change lens position to the
lens actuator, the AFM driver sets bit 1 of afm.status to
1. The value of the bit remains 1 until the AFM driver
gets information that the lens is not moving (either has
stopped at the desired new position or has failed to
reach it). The AF driver waits through all times when the
lens is moving by having afm.status updated once every
frame, reading its bit 1 and immediately going back to
sleep if it equals 1.
6posMinuchar
0 RW Lower limit of physical position range
3
7 posMax uchar
0 RW Upper limit of physical position range. Can be set below
afm.posMin to swap forward (+) and backward (-)
directions of lens movement.
8 posMacro uchar
0 RW Logical macro position