TAS5717_14 Datasheet, PDF (27/68 Pages) Texas Instruments – 10-W/15-W Digital Audio Power Amplifier with Integrated Cap-Free HP Amplifier

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I²C SERIAL CONTROL INTERFACE
TAS5717
TAS5719
SLOS655A – NOVEMBER 2010 – REVISED FEBRUARY 2011
The TAS5717/9 DAP has a bidirectional I²C interface that is compatible with the Inter IC (I²C) bus protocol and
supports both 100-kHz and 400-kHz data transfer rates for single- and multiple-yte write and read operations.
This is a slave-only device that does not support a multimaster bus environment or wait-state insertion. The
control interface is used to program the registers of the device and to read device status.
The DAP supports the standard-mode I²C bus operation (100 kHz maximum) and the fast I²C bus operation
(400 kHz maximum). The DAP performs all I²C operations without I²C wait cycles.
General I²C Operation
The I²C bus employs two signals; SDA (data) and SCL (clock), to communicate between integrated circuits in a
system. Data is transferred on the bus serially, one bit at a time. The address and data can be transferred in byte
(8-bit) format, with the most significant bit (MSB) transferred first. In addition, each byte transferred on the bus is
acknowledged by the receiving device with an acknowledge bit. Each transfer operation begins with the master
device driving a start condition on the bus and ends with the master device driving a stop condition on the bus.
The bus uses transitions on the data pin (SDA) while the clock is high to indicate start and stop conditions. A
high-to-low transition on SDA indicates a start and a low-to-high transition indicates a stop. Normal data-bit
transitions must occur within the low time of the clock period. These conditions are shown in Figure 35. The
master generates the 7-bit slave address and the read/write (R/W) bit to open communication with another
device and then waits for an acknowledge condition. The TAS5717/9 holds SDA low during the acknowledge
clock period to indicate an acknowledgment. When this occurs, the master transmits the next byte of the
sequence. Each device is addressed by a unique 7-bit slave address plus R/W bit (1 byte). All compatible
devices share the same signals via a bidirectional bus using a wired-AND connection. An external pullup resistor
must be used for the SDA and SCL signals to set the high level for the bus.
SDA
7-Bit Slave Address
R/
W
A
8-Bit Register Address (N)
A
8-Bit Register Data For
Address (N)
A
8-Bit Register Data For
Address (N)
A
765432 10
765432 10
765432 10
765432 10
SCL
Start
Figure 35. Typical I²C Sequence
Stop
T0035-01
There is no limit on the number of bytes that can be transmitted between start and stop conditions. When the last
word transfers, the master generates a stop condition to release the bus. A generic data transfer sequence is
shown in Figure 35.
The 7-bit address for TAS5717/9 is 0101 010 (0x54) or 0101 011 (0x56) defined by A_SEL (external pulldown for
0x54 and pullup for 0x56).Stero device with Headphone should use 0x54 as its device address.
Single- and Multiple-Byte Transfers
The serial control interface supports both single-byte and multiple-byte read/write operations for subaddresses
0x00 to 0x1F. However, for the subaddresses 0x20 to 0xFF, the serial control interface supports only
multiple-byte read/write operations (in multiples of 4 bytes).
During multiple-byte read operations, the DAP responds with data, a byte at a time, starting at the subaddress
assigned, as long as the master device continues to respond with acknowledges. If a particular subaddress does
not contain 32 bits, the unused bits are read as logic 0.
During multiple-byte write operations, the DAP compares the number of bytes transmitted to the number of bytes
that are required for each specific subaddress. For example, if a write command is received for a biquad
subaddress, the DAP expects to receive five 32-bit words. If fewer than five 32-bit data words have been
received when a stop command (or another start command) is received, the data received is discarded.
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Product Folder Link(s): TAS5717 TAS5719
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