ADNS-2051 Avago Technologies US Inc., ADNS-2051 Datasheet - Page 20

• Manufacturer Part Number: ADNS-2051
• Description: Optical Mouse Sensor,DIP
• Manufacturer: Avago Technologies US Inc.

Specifications of ADNS-2051

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: Q2072083C

20
Forcing the SDIO Line to the Hi-Z State
There are times when the SDIO line from the ADNS-2051
should be in the Hi-Z state. If the microprocessor has
completed a write to the ADNS-2051, 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 ADNS-2051 will hold the D0 state on
SDIO until a falling edge of SCLK.
Figure 30. SDIO Hi-Z state and timing
Required Timing between Read and Write Commands
(tsxx)
There are minimum timing requirements between read
and write commands on the serial port.
Figure 31. Timing between two write commands
If the rising edge of SCLK for the last address bit of
the read command occurs before the 100 microsec-
ond required delay, then the write command may not
complete correctly.
Figure 32. Timing between write and read commands
PD
SDIO
SCLK
SCLK
100 μs
ADDRESS
ADDRESS
WRITE OPERATION
WRITE OPERATION
Hi-Z
DATA
DATA
ADDRESS
t
t
SWW
SWR
WRITE OPERATION
>100 μs
>100 μs
To place the SDIO pin into the Hi-Z state, raise the PD
pin for 100 μs (min). The PD pin can stay high, with the
ADNS-2051 in the shutdown state, or the PD pin can be
lowered, returning the ADNS-2051 to normal operation.
The SDIO line will now be in the Hi-Z state.
If the rising edge of the SCLK for the last data bit of the
second write command occurs before the 100 microsec-
ond required delay, then the first write command may
not complete correctly.
NEXT READ OPERATION
ADDRESS
DATA