PixArt Imaging Inc.
PAN301BSI-208
CMOS Optical Mouse Sensor
changed on falling edges of SCLK and read on every rising edge of SCLK. The micro-controller must go
to a high Z state after the last address data bit. The PAN301BSI-208 will go to the high Z state after the
last data bit.
SCLK
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
SDIO
0
A6 A5 A4 A3 A2 A1 A0
D7 D6 D5 D4 D3 D2 D1 D0
SDIO driven by Micro-controller
SDIO driven by PAN301BSI-208
Note "A"
Note "B"
1. Micro-controller send address to PAN301BSI-208.
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. PAN301BSI-208 send data to Micro-controller .
2. PAN301BSI-208 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
SDIO driven by micro-controller
D0
Figure 11. Read operation
6.2 Re-Synchronous Serial Interface
There are times when the SDIO line from the PAN301BSI-208 should be in the Hi-Z state. If the
microprocessor has completed a write to the PAN301BSI-208, 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
PAN301BSI-208 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 line, and then toggle the SCLK line from high to low to high. The SDIO
line will now be in the Hi-Z state. The PAN301BSI-208 and the micro-controller might get out of
synchronization due to following condition.
PD
1us,min
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
2
3
4
5
6
7
8
9
SCLK
SDIO
Hi-Z
Figure 12. Forcing PAN301BSI-208 SDIO line to the Hi-Z state
ADDRESS(R/W)
DATA
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PixArt Imaging Inc.
16
E-mail: fae_service@pixart.com.tw
V1.1, MAY. 2004
PIXART [ PIXART IMAGING INC. ]
