ADNS2051 datasheet(18/40 Pages) HP

18 / 40 page

Read Operation

A read operation, which means

that data is going from the

ADNS-2051 to the micro-

controller, is always initiated by

the micro-controller and consists

of two bytes. The first byte

contains the address, is written

by the micro-controller, and has a

“0” as its MSB to indicate data

direction. The second byte con-

tains the data and is driven by the

ADNS-2051. The transfer is syn-

chronized by SCLK. SDIO is

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 ADNS-2051

will go to the high Z state after

the last data bit (see detail “B”

in Figure 28). One other thing

to note during a read operation

is that SCLK will need to be

delayed after the last address

data bit to ensure that the

ADNS-2051 has at least 100

µs to

prepare the requested data. This

is shown in the timing

diagrams below.

Figure 27. Read operation.

Figure 28. Microcontroller to ADNS-2051 SDIO handoff.

Figure 29. ADNS-2051 to microcontroller SDIO handoff.

Note:

The 120 ns high state of SCLK is the minimum data hold time of the ADNS-2051. Since the falling edge of SCLK

is actually the start of the next read or write command, the ADNS-2051 will hold the state of D0 on the SDIO line

until the falling edge of SCLK. In both write and read operations, SCLK is driven by the micro-controller.

Serial port communications is not allowed while PD (power down) is high. See “Error Detection and

Recovery” regarding re-synchronizing via PD.

DETAIL "A"

MICROCONTROLLER

TO ADNS-2051

SDIO HANDOFF

SDIO

SCLK

60 ns, MIN.

tHOLD

100 µs, MIN.

120 ns, MIN.

0 ns, MIN.

120 ns, MAX.

0 ns, MIN.

120 ns, MAX.

Hi-Z

10 ns, MAX.

120 ns, MIN.

R/W BIT OF NEXT ADDRESS

SCLK

SDIO

DETAIL "B"

ADNS-2051 TO

MICROCONTROLLER

SDIO HANDOFF

DRIVEN BY MICRO

RELEASED BY 2051

SCLK

CYCLE #

SCLK

SDIO

SDIO DRIVEN BY MICRO-CONTROLLER

SDIO DRIVEN BY ADNS-2051

DETAIL "A"

DETAIL "B"

ADNS2051 Datasheet(PDF) 18 Page - Agilent(Hewlett-Packard)

ADNS2051 Datasheet(HTML) 18 Page - Agilent(Hewlett-Packard)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Datasheet Download

Link URL