ADV7340_15 Datasheet, PDF (29/108 Pages) Analog Devices – Multiformat Video Encoder, Six 12-Bit Noise Shaped Video DACS

Data Sheet
MPU PORT DESCRIPTION
Devices such as a microprocessor can communicate with the
ADV7340/ADV7341 through a 2-wire serial (I²C-compatible)
bus. After power-up or reset, the MPU port is configured for
I²C operation.
I²C OPERATION
The ADV7340/ADV7341 support a 2-wire serial (I²C-compatible)
microprocessor bus driving multiple peripherals. This port
operates in an open-drain configuration. Two wires, serial data
(SDA) and serial clock (SCL), carry information between any
device connected to the bus and the ADV7340/ADV7341. The
slave address of the device depends on the device (ADV7340 or
ADV7341), the operation (read or write), and the state of the
ALSB pin (0 or 1). See Table 16, Figure 47, and Figure 48. The
LSB sets either a read or a write operation. Logic 1 corresponds to
a read operation, and Logic 0 corresponds to a write operation.
A1 is controlled by setting the ALSB pin of the ADV7340/
ADV7341 to Logic 0 or Logic 1.
Table 16. ADV7340/ADV7341 I²C Slave Addresses
Device
ALSB
Operation Slave Address
ADV7340 0
Write
0xD4
0
Read
0xD5
1
Write
0xD6
1
Read
0xD7
ADV7341 0
Write
0x54
0
Read
0x55
1
Write
0x56
1
Read
0x57
1
1
0
1
0
1 A1 X
ADDRESS
CONTROL
SET UP BY
ALSB
READ/WRITE
CONTROL
0 WRITE
1 READ
Figure 47. ADV7340 I²C Slave Address
0
1
0
1
0
1 A1 X
ADDRESS
CONTROL
SET UP BY
ALSB
READ/WRITE
CONTROL
0 WRITE
1 READ
Figure 48. ADV7341 I²C Slave Address
Analog Devices, Inc., strongly recommends tying ALSB to
VDD_IO. If this is not done, a power supply sequence (PSS) may be
required. For more information on the PSS, see the Power Supply
ADV7340/ADV7341
Sequencing section. The various devices on the bus use the
following protocol. The master initiates a data transfer by
establishing a start condition, defined by a high-to-low
transition on SDA while SCL remains high. This indicates that
an address/data stream follows. All peripherals respond to the
start condition and shift the next eight bits (7-bit address plus
the R/W bit). The bits are transferred from MSB down to LSB.
The peripheral that recognizes the transmitted address responds
by pulling the data line low during the ninth clock pulse. This is
known as an acknowledge bit. All other devices withdraw from
the bus at this point and maintain an idle condition. The idle
condition occurs when the device monitors the SDA and SCL
lines waiting for the start condition and the correct transmitted
address. The R/W bit determines the direction of the data.
Logic 0 on the LSB of the first byte means that the master writes
information to the peripheral. Logic 1 on the LSB of the first byte
means that the master reads information from the peripheral.
The ADV7340/ADV7341 act as a standard slave device on the
bus. The data on the SDA pin is eight bits long, supporting the
7-bit addresses plus the R/W bit. It interprets the first byte as
the device address and the second byte as the starting subaddress.
There is a subaddress auto-increment facility. This allows data
to be written to or read from registers in ascending subaddress
sequence starting at any valid subaddress. A data transfer is
always terminated by a stop condition. The user can also access
any unique subaddress register on a one-by-one basis without
updating all the registers.
Stop and start conditions can be detected at any stage during the
data transfer. If these conditions are asserted out of sequence
with normal read and write operations, they cause an immediate
jump to the idle condition. During a given SCL high period, the
user should issue only a start condition, a stop condition, or a
stop condition followed by a start condition. If an invalid sub-
address is issued by the user, the ADV7340/ADV7341 do not
issue an acknowledge but return to the idle condition. If the user
uses the auto-increment method of addressing the encoder and
exceeds the highest subaddress, the following actions are taken:
• In read mode, the highest subaddress register contents are
output until the master device issues a no acknowledge. This
indicates the end of a read. A no acknowledge condition
occurs when the SDA line is not pulled low on the ninth pulse.
• In write mode, the data for the invalid byte is not loaded
into any subaddress register, a no acknowledge is issued by
the ADV7340/ADV7341, and the parts return to the idle
condition.
Figure 49 shows a data transfer for a write sequence and the start
and stop conditions. Figure 50 shows bus write and read
sequences.
Rev. C | Page 29 of 108