PixArt Imaging Inc.
PAN101B
CMOS Optical Navigation Sensor
SCLK
SDIO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Hi-z
Hi-z
DON'T
CARE
R/W bit of next address
0
A6 A5 A4 A3 A2 A1 A0
D7 D6 D5 D4 D3 D2 D1 D0
SDIO driven by Micro-controller
SDIO driven by PAN101B
Note "A"
Note "B"
1. Micro-controller send address to PAN101B.
2. Micro-controller release and set SDIO to Hi-Z after the last address bit.
Note "A"
SCLK
SDIO
8
9
7
A1
Hi-Z
A0
D7
tHOLD
3us,min
1. PAN101B send data to Micro-controller .
2. PAN101B release and set SDIO to Hi-Z after the last data bit.
Note "B"
SCLK
SDIO
16
1
Hi-Z
R/W bit of next address
D0
SDIO driven by micro-controller
Figure 14. Read Operation
7.2 Re-Synchronous Serial Interface
There are times when the SDIO line from the PAN101B should be in the Hi-Z state. If the microprocessor
has completed a write to the PAN101B, the SDIO line is Hi-Z, since the SDIO pin is still configured as an
input. However, if the last operation from the microprocessor was a read, the PAN101B will hold the D0
state on SDIO until a rising edge of SCLK. To place the SDIO pin into the Hi-Z state, first raise the PD
pin, and then toggle the SCLK line from high to low to high. The SDIO line will now be in the Hi-Z state.
The PAN101B and the micro-controller might get out of synchronization due to following condition.
7.2.1 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 PAN101B 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.
7.2.2 Firmware flaws error, or others error
The PAN101B and the micro-controller might get out of synchronization due to micro-controller
firmware flaws. The PD pin can stay high, with the PAN101B in the shutdown state, or the PD pin can be
lowered, returning the PAN101B to normal operation.
If the microprocessor and the PAN101B 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 PAN101B will reset the serial port but will not reset the registers and be prepared
for the beginning of a new transmission
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14
V1.4, FEB. 2003
PixArt Imaging Inc.
E-mail: fae_service@pixart.com.tw
PIXART [ PIXART IMAGING INC. ]
