adate302-02 Analog Devices, Inc., adate302-02 Datasheet - Page 37

• Manufacturer Part Number: adate302-02
• Description: 500 Mhz Dual Integrated Dcl With Differential Drive/receive, Level Setting Dacs, And Per Pin Pmu
• Manufacturer: Analog Devices, Inc.

READ OPERATION
The read operation is a two-stage operation. First, a word is
shifted in, specifying which register to read. CS is deasserted for
three clock cycles, and then a second word is shifted in to get
the readback data. This second word can be either another
operation or an NOP address. If another operation is shifted in,
it needs to shift in at least eight bits of data to read back the
RDATA IS THE REGISTER VALUE BEING READ.
OUTPUT
OUTPUT
OUTPUT
SDOUT
SDOUT
SDOUT
INPUT
INPUT
INPUT
INPUT
INPUT
INPUT
INPUT
INPUT
INPUT
SCLK
SCLK
SCLK
SDIN
SDIN
SDIN
CS
CS
CS
0
RDATA[15]
0
DATA[15:0], VALUE IS A DON’T CARE
DATA[15:0], VALUE IS A DON’T CARE
1
1
RDATA[14]
READ INSTRUCTION
2
2
X
13
RDATA[2]
13
14
RDATA[1]
Figure 84. SPI Read—Details of Read Request
14
Figure 85. SPI Read—Details of Read Out
15
RDATA[0]
15
Figure 83. SPI Read Overview
Rev. 0 | Page 37 of 52
CH[1]
CH[1]
16
16
X
CH[0]
CH[0]
17
X
17
previous specified data. The NOP address can be used for this
read if there is no need to write/read another register. It is
strongly recommended that the NOP address be used for all
reads for clarity of operations.
Any register read that is less than 16 bits has zeros filled in the
top bits to make it a 16-bit word.
R/W = 1
R/W
18
18
ADDR[4] ADDR[3] ADDR[2] ADDR[1] ADDR[0]
19
19
ADDR[4:0] = 0x00 (NOP)
20
20
READ DATA
21
21
NOP
X
22
22
23
23
24
24
ADATE302-02
25
X
25
X
X
X