AD9961BCPZRL Analog Devices Inc, AD9961BCPZRL Datasheet - Page 20
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AD9961BCPZRL
Manufacturer Part Number
AD9961BCPZRL
Description
Dual 16B, 200 MSPS D-A Converter
Manufacturer
Analog Devices Inc
Datasheet
1.AD9961BCPZRL.pdf
(60 pages)
Specifications of AD9961BCPZRL
Features
*
Package / Case
72-VFQFN, CSP Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
AD9961/AD9963
SERIAL CONTROL PORT
The AD9961/AD9963 serial control ports are a flexible,
synchronous, serial communications port that allows an easy
interface with many industry-standard microcontrollers and
microprocessors. The AD9961/AD9963 serial control ports are
compatible with most synchronous transfer formats, including
both the Motorola SPI and Intel® SSR® protocols. The serial
control port allows read/write access to all registers that
configure the AD9961/AD9963. Single or multiple byte
transfers are supported, as well as MSB first or LSB first transfer
formats.
Serial Control Port Pin Descriptions
The serial control port has three pins, SCLK, SDIO, and CS
•
•
•
GENERAL OPERATION OF SERIAL CONTROL PORT
The falling edge of CS
SCLK, determines the start of a communication cycle. There
are two parts to a communication cycle with the AD9961/
AD9963. The first part writes a 16-bit instruction word into the
AD9961/AD9963, coincident with the first 16 SCLK rising
edges. The instruction word provides the AD9961/AD9963
serial control ports with information regarding the data
transfer, which is the second part of the communication cycle.
The instruction word defines whether the upcoming data
transfer is a read or a write, the number of bytes in the data
transfer, and the starting register address for the first byte of the
data transfer.
Instruction Header
The MSB of the instruction word is R/ W
whether the serial port transfer is a read or a write. The next
two bits, N1:N0, indicate the length of the transfer in bytes. The
final 13 bits are the address (A12 to A0) at which to begin the
read or write operation.
For a write, the instruction word is followed by the number of
bytes of data indicated by Bit N1 to Bit N0 (see
SCLK (serial clock) is the input clock used to register serial
control port reads and writes. Write data bits are registered
on the rising edge of this clock, and read data bits are
registered on the falling edge. This pin is internally pulled
down by a 30 kΩ resistor to ground.
SDIO (serial data input/output) functions as both the
input and output data pin.
CS (chip select bar) is an active low control that gates the
read and write cycles. When
impedance state and SCLK is disabled. This pin is
internally pulled up by a 30 kΩ resistor to DRVDD.
, in conjunction with the rising edge of
CS is high, SDIO is in a high
, which indicates
Table 10).
:
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Table 10. Byte Transfer Count
N1
0
0
1
1
A12 to A0 select the address within the register map that is
written to or read from during the data transfer portion of the
communications cycle. For multibyte transfers, the address is
the starting byte address.
Only Address Bits[A7:A0] are needed to cover the range of
the 0xFF registers used by the AD9961/AD9963. Address
Bits[A12:A8] must always be 0.
Write Transfer
If the instruction header indicates a write operation, the bytes
of data written onto the SDIO line are loaded into the serial
control port buffer of the AD9961/AD9963. Data bits are
registered on the rising edge of SCLK.
The length of the transfer (1 byte, 2 byte, 3 bytes, or streaming
mode) is indicated by two bits (N1:N0) in the instruction byte.
During a write, streaming mode does not skip over unused or
reserved registers; therefore, the user must know what bit
pattern to write to the reserved registers to preserve proper
operation of the part. It does not matter what data is written to
unused registers.
Read Transfer
If the instruction word is for a read operation, the next N × 8
SCLK cycles clock out the data from the address specified in the
instruction word, where N is 1 to 3 as determined by N1:N0.
If N = 4, the read operation is in streaming mode, and
continues until CS
reserved or unused registers. The readback data is valid on the
falling edge of SCLK.
MSB/LSB First Transfers
The AD9961/AD9963 instruction word and byte data formats
can be selected to be MSB first or LSB first. The default for the
AD9961/AD9963 is MSB first. When MSB first mode is active,
the instruction and data bytes must be written from MSB to
LSB. Multibyte data transfers in MSB first format start with an
instruction byte that includes the register address of the most
significant data byte. Subsequent data bytes must follow in
order from the high address to the low address. In MSB first
mode, the serial control port internal address generator
decrements for each data byte of the multibyte transfer cycle.
When LSB first is active, the instruction and data bytes must be
written from LSB to MSB. Multibyte data transfers in LSB first
format start with an instruction byte that includes the register
address of the least significant data byte followed by multiple data
bytes. The internal byte address generator of the serial control
port increments for each byte of the multibyte transfer cycle.
N0
0
1
0
1
is raised. Streaming mode does not skip over
Bytes to Transfer
1
2
3
Streaming mode