CYONS1001X_09 Datasheet, PDF (8/24 Pages) Cypress Semiconductor – OvationONS Laser Navigation Sensors

CYONS1001x
Power Management
The CYONS1001x sensors are equipped with power
management features designed to meet the needs of their target
applications. The CYONS1001L and CYONS1001T sensors,
which target general purpose tracking applications such as
wireless mice, offer two power saving sleep modes that extend
battery life, and an ultra low power hibernate mode that is used
to meet USB suspend requirements. The CYONS1001,
CYONS1001G, and CYONS1001U sensors are optimized for
high performance applications that require fast response at all
times; therefore, these devices only support hibernate mode.
The operational modes supported by the CYONS1001x sensors
are summarized in Table 7. The current consumption of each
mode is listed in Table 5 on page 5.
Table 7. Summary of CYONS1001x Operational Modes
Mode
Tracking
Nap
Sleep
Hibernate
CYONS1001,
1001G, 1001U
Yes
No
No
Yes
CYONS
1001L, 1001T
Yes
Yes
Yes
Yes
Tracking Mode
In tracking mode, the sensor is in motion and tracking x/y
changes. Tracking mode consumes the most power, with fast
motion drawing slightly more current than slow motion. After
approximately 4 seconds of inactivity, the sensor automatically
switches to nap mode.
Nap Mode
In nap mode, the sensor can detect gross motion. If motion is
detected, the sensor switches to tracking mode within 20 ms. If
motion is not detected for 30 seconds after entering nap mode,
the sensor automatically switches to sleep mode.
Sleep Mode
In sleep mode, the sensor can also detect gross motion. If motion
is detected, the sensor enters tracking mode within 250 ms. If
motion is not detected, the sensor remains in sleep mode
indefinitely.
Hibernate Mode
The controller can place the sensor in hibernate mode by
asserting the SHUTDOWN pin. In this state, the sensor cannot
detect motion, and can only be activated by resetting the
SHUTDOWN pin to LOW. Startup time from hibernate mode to
full tracking capability is 20 ms max.
Passive Power Management
The CYONS1001L and CYONS1001T sensors are ideal for
passive power management. Unlike other laser sensors, these
devices control their own low power modes, freeing the
application designer from concerns about power minimization.
No additional firmware is required to take advantage of their
self-adjusting power-saving nap and sleep modes.
Active Power Management
For applications requiring further power reduction, mouse
firmware can use the SHUTDOWN and MOTION pins to
implement active power management. This means the controller
actively switches the sensor between tracking and hibernate
modes to reap the benefit of low current draw during hibernate
mode.
A typical requirement for a mouse is that mouse movement must
be able to wake the system from a low power operating state.
Though the sensor is unable to detect motion in hibernate state,
firmware can be designed to periodically check for motion by
temporarily bringing the sensor out of hibernation. A
recommended approach to active power management is as
follows:
1. Choose a motion-check period, such as once per second.
Longer periods save more power, but also result in longer
delays in detecting motion.
2. Assert the SHUTDOWN pin to put the sensor in hibernate
mode.
3. At the start of each motion-check period, deassert the
SHUTDOWN line, then wait until the sensor sets the MOTION
line high (20 ms or less).
4. Send two read tracking data commands to the sensor,
ensuring sufficient delay between the commands. The sensor
reports zeroes in response to the first command to avoid
sending spurious data. The second report has valid x-y data.
5. If the data is two counts or more for either x or y, the sensor
has been moved and the controller must initiate its wakeup
sequence. If the data is 1 count or less for both x and y, the
sensor has not been moved and the controller can reassert
SHUTDOWN until the next motion-check period.
Document Number: 001-06398 Rev. *J
Page 8 of 24
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