PixArt Imaging Inc.
PAN301BSI-208
CMOS Optical Mouse Sensor
6.2.1 USB Suspend
Termination of a transmission by the micro-controller may sometimes be required (for example, due to a
USB suspend interrupt during a read operation). To accomplish this the micro-controller should raise PD.
The PAN301BSI-208 will not write to any register and will reset the serial port (but nothing else) and be
prepared for the beginning of future transmissions after PD goes low.
6.2.2 Firmware Flaws Error, or Others Error
The PAN301BSI-208 and the micro-controller might get out of synchronization due to micro-controller
firmware flaws. The PD pin can stay high, with the PAN301BSI-208 in the shutdown state, or the PD pin
can be lowered, returning the PAN301BSI-208 to normal operation.
If the microprocessor and the PAN301BSI-208 get out of sync, then the data either written or read from
the registers will be incorrect. In such a case, an easy way to solve this is to raise PD to re-sync the parts
after an incorrect read. The PAN301BSI-208 will reset the serial port but will not reset the registers and
be prepared for the beginning of a new transmission.
6.2.3 Power On Problem
The problem occurs if the PAN301BSI-208 powers up before the microprocessor sets the SCLK and
SDIO lines to be output.
6.2.4 ESD Events
The PAN301BSI-208 and the micro-controller might get out of synchronization due to ESD events.
If the PAN301BSI-208 and the micro-controller might get out of synchronization due to power on
problem or ESD events. An easy way to solve this is to soft reset the PAN301BSI-208.
VDD
1us,min
PD
SCLK
SDIO
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
Hi-Z
ADDRESS(R/W)
DATA
Figure 13. Soft reset the PAN301BSI-208 (Reset full chip and SDIO line set to Hi-Z state)
6.3 Collision Detection on SDIO
The only time that the PAN301BSI-208 drives the SDIO line is during a READ operation. To avoid data
collisions, the micro-controller should release SDIO before the falling edge of SCLK after the last address
bit. The PAN301BSI-208 begins to drive SDIO after the next falling edge of SCLK. The PAN301BSI-
208 release SDIO of the rising SCLK edge after the last data bit. The micro-controller can begin driving
SDIO any time after that. In order to maintain low power consumption in normal operation or when the
PD pin is pulled high, the micro-controller should not leave SDIO floating until the next transmission
(although that will not cause any communication difficulties).
6.4 Serial Interface Watchdog Timer Timeout
When there are only two pins to read register from PAN301BSI-208, and PD pin can’t be used to re-
synchronous function. If the microprocessor and the PAN301BSI-208 get out of sync, then the data either
written or read from the registers will be incorrect. In such a case, an easy way to solve this condition is to
toggle the SCLK line from high to low to high and wait at least tSIWTT to re-sync the parts after an
incorrect read. The PAN301BSI-208 will reset the serial port but will not reset the registers and be
prepared for the beginning of a new transmission.
All rights strictly reserved any portion in this paper shall not be reproduced, copied or transformed to any other forms without permission.
17
PixArt Imaging Inc.
E-mail: fae_service@pixart.com.tw
V1.1, MAY. 2004
PIXART [ PIXART IMAGING INC. ]
