AD9983A/PCBZ Analog Devices Inc, AD9983A/PCBZ Datasheet - Page 21

• Manufacturer Part Number: AD9983A/PCBZ
• Description: Pb-free EVALUATION Kit AD9983A
• Manufacturer: Analog Devices Inc
• Series: Advantiv®r

Specifications of AD9983A/PCBZ

• Main Purpose: Video, Video Processing
• Embedded: No
• Utilized Ic / Part: AD9983A
• Primary Attributes: 3 x 8-Bit 140 MSPS ADC's
• Secondary Attributes: Integrated PLL & VCO
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2-WIRE SERIAL CONTROL PORT
A 2-wire serial interface control interface is provided. Up to two
AD9983A devices may be connected to the 2-wire serial
interface, with each device having a unique address.
The 2-wire serial interface comprises a clock (SCL) and a bi-
directional data (SDA) pin. The analog flat panel interface acts
as a slave for receiving and transmitting data over the serial
interface. When the serial interface is not active, the logic levels
on SCL and SDA are pulled high by external pull-up resistors.
Data received or transmitted on the SDA line must be stable for
the duration of the positive-going SCL pulse. Data on SDA must
change only when SCL is low. If SDA changes state while SCL is
high, the serial interface interprets that action as a start or stop
sequence.
The following are the five components to serial bus operation:
•
•
•
•
•
When the serial interface is inactive (SCL and SDA are high),
communications are initiated by sending a start signal. The start
signal is a high-to-low transition on SDA while SCL is high.
This signal alerts all slaved devices that a data transfer sequence
is coming.
The first 8 bits of data transferred after a start signal comprise a
7-bit slave address (the first 7 bits) and a single R/ W bit (the
eighth bit). The R/ W bit indicates the direction of data transfer,
read from 1 or write to 0 on the slave device. If the transmitted
slave address matches the address of the device, the AD9983A
acknowledges the match by bringing SDA low on the ninth SCL
pulse. If the addresses do not match, the AD9983A does not
acknowledge it.
Start signal
Slave address byte
Base register address byte
Data byte to read or write
Stop signal
SDA
SCL
t
t
STAH
BUFF
t
DHO
t
DAL
Figure 17. Serial Port Read/Write Timing
t
DAH
t
DSU
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Table 13. Serial Port Addresses
Bit 7
A6 (MSB)
1
1
DATA TRANSFER VIA SERIAL INTERFACE
For each byte of data read or written, the MSB is the first bit in
the sequence.
If the AD9983A does not acknowledge the master device during
a write sequence, the SDA remains high so the master can gen-
erate a stop signal. If the master device does not acknowledge
the AD9983A during a read sequence, the AD9983A interprets
this as end of data. The SDA remains high so the master can
generate a stop signal.
Writing data to specific control registers of the AD9983A
requires writing to the 8-bit address of the control register of
interest after the slave address has been established. This control
register address is the base address for subsequent write
operations. The base address auto-increments by one for each
byte of data written after the data byte intended for the base
address. If more bytes are transferred than there are available
addresses, the address does not increment and remains at its
maximum value of 0x2E. Any base address higher than 0x2E
will not produce an acknowledge signal. Data are read from the
control registers of the AD9983A in a similar manner. Reading
requires two data transfer operations:
The base address must be written with the R/ W bit of the slave
address byte low to set up a sequential read operation. Reading
(the R/ W bit of the slave address byte high) begins at the
previously established base address. The address of the read
register auto-increments after each byte is transferred.
To terminate a read/write sequence to the AD9983A, a stop
signal must be sent. A stop signal comprises a low-to-high
transition of SDA while SCL is high.
A repeated start signal occurs when the master device driving
the serial interface generates a start signal without first genera-
ting a stop signal to terminate the current communication. This
is used to change the mode of communication (read, write)
between the slave and master without releasing the serial
interface lines.
t
STASU
Bit 6
A5
0
0
Bit 5
A4
0
0
t
Bit 4
A3
1
1
STOSU
Bit 3
A2
1
1
Bit 2
A1
0
0
AD9983A
Bit 1
A0
0
1