PixArt Imaging Inc.
ADNS-7550 Integrated Molded Lead-Frame DIP Sensor
Notes on Power-up
Notes on Shutdown
The ADNS-7550 does not perform an internal power up
self-reset; the POWER_UP_RESET register must be written
every time power is applied. The appropriate sequence is
as follows:
The ADNS-7550 can be set in Shutdown mode by
writing 0xe7 to register 0x3b. The SPI port should not
be accessed when Shutdown mode is asserted, except
the power-up command (writing 0x5a to register 0x3a).
(Other ICs on the same SPI bus can be accessed, as long
as the sensor’s NCS pin is not asserted.) The table below
shows the state of various pins during shutdown. To
deassert Shutdown mode:
i.
Apply power to VDD5 and VDDIO in any order, with
the delay of no more than 100ms in between each
supply. Ensure all supplies are stable.
ii. Drive NCS high, then low to reset the SPI port.
iii. Write 0x5a to register 0x3a.
i. Write 0x5a to register 0x3a
ii. Wait for at least one frame.
iii. Clear observation register.
iv. Wait at least one frame
iv. Wait for at least one frame.
v. Clear observation register.
vi. Wait at least one frame and check observation
register, all bits 0-3 must be set.
v. Check observation register, all bits 0-3 must be set to
1.
vii. Read from registers 0x02, 0x03, 0x04 and 0x05 (or
read these same 4 bytes from burst motion register
0x42) one time regardless of the motion pin state.
vi. Write 0x27 to register 0x3C
vii. Write 0x0a to register 0x22
viii. Write 0x01 to register 0x21
ix. Write 0x32 to register 0x3C
x. Write 0x20 to register 0x23
xi. Write 0x05 to register 0x3C
xii. Write 0xB9 to register 0x37
xiii. Any register settings must then be reloaded.
viii. Write 0x27 to register 0x3C
ix. Write 0x0a to register 0x22
x. Write 0x01 to register 0x21
xi. Write 0x32 to register 0x3C
xii. Write 0x20 to register 0x23
xiii. Write 0x05 to register 0x3C
xiv. Write 0xB9 to register 0x37
Pin
Status when Shutdown Mode
Functional [1]
During power-up there will be a period of time after the
power supply is high but before any clocks are available.
The table below shows the state of the various pins
during power-up and reset.
NCS
MISO
Undefined [2]
SCLK
Ignore if NCS = 1 [3]
Ignore if NCS = 1 [4]
High(off)
MOSI
State of Signal Pins After VDD is Valid
LASER_NEN
MOTION
Before Reset
On
Undefined [2]
Pin
Power-Up
NCS High
NCS Low After Reset
1. NCS pin must be held to 1 (high) if SPI bus is shared with other
devices. It is recommended to hold to 1 (high) during Power
Down unless powering up the Sensor. It must be held to 0 (low) if
the sensor is to be re-powered up from shutdown (writing 0x5a to
register 0x3a).
NCS
Functional
Hi
Low
Functional
Depends on
MISO
SCLK
MOSI
Undefined Undefined Functional NCS
Depends on
Functional NCS
Depends on
Functional NCS
2. Depend on last state
Ignored
Ignored
Ignored
Ignored
3. SCLK is ignore if NCS is 1 (high). It is functional if NCS is 0 (low).
4. MOSI is ignore if NCS is 1 (high). If NCS is 0 (low), any command
present on the MOSI pin will be ignored except power-up command
(writing 0x5a to register 0x3a).
Note:
MOTION Undefined Undefined Undefined Functional
LASER_
There are long wakeup times from shutdown. These features should
not be used for power management during normal mouse motion.
NEN
Undefined Undefined Undefined Functional
All rights strictly reserved any portion in this paper shall not be reproduced, copied or transformed to any other forms without permission.
PixArt Imaging Inc.
E-mail: fae_service@pixart.com.tw
17
PIXART [ PIXART IMAGING INC. ]
