MT9M019 Aptina Imaging Corporation, MT9M019 Datasheet - Page 22

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

Power-On Reset Sequence
Soft Reset Sequence
Signal State During Reset
PDF: 7723845879/Source:2828556980
MT9D019_DS - Rev. F 5/10 EN
1. The negation of the RESET_N input.
2. A timeout of the internal power-on reset circuit.
When power is applied to the MT9M019, it enters a low-power hardware standby state.
Exit from this state is controlled by the later of two events:
It is possible to hold RESET_N permanently negated and rely upon the internal power-
on reset circuit.
The RESET_N signal is functionally equivalent to the SMIA-specified XSHUTDOWN
signal.
When RESET_N is asserted it asynchronously resets the sensor, truncating any frame
that is in progress.
While RESET_N is asserted (or the internal power-on reset circuit is active) the
MT9M019 is in its lowest-powered, powered-up state; the internal PLL is disabled, the
CCP2 serializer is disabled and internal clocks are gated off.
When the sensor leaves the hardware standby state, it performs an internal initialization
sequence that takes 800 EXTCLK cycles. After this, it enters a low-power software
standby state. While the initialization sequence is in progress, the MT9M019 will not
respond to read transactions on its two-wire serial interface. Therefore, a method to
determine when the initialization sequence has completed is to poll a sensor register; for
example, R0x0000. While the initialization sequence is in progress, the sensor will not
respond to its device address and so reads from the sensor will result in a NACK on the
two-wire serial interface bus. When the sequence has completed, reads will return the
operational value for the register (0x14 if R0x0000 is read).
When the sensor leaves software standby mode and enables the VCO, an internal delay
will keep the PLL disconnected for 6,750 EXTCLKs so that the PLL can lock.
The MT9M019 can be reset under software control by writing “1” to software_reset
(R0x0103). A software reset asynchronously resets the sensor, truncating any frame that
is in progress. The sensor briefly enters the hardware standby state and then starts its
internal initialization sequence. At this point, the behavior is exactly the same as for the
power-on reset sequence.
Table 7 on page 23 shows the state of the signal interface during hardware standby
(RESET_N asserted) and the default state during software standby (after exit from hard-
ware standby and before any registers within the sensor have been changed from their
default power-up values).
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MT9M019: 1/5-Inch 1.3Mp CMOS Digital Image Sensor
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Control of the Signal Interface
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