ZHCSGM5A August 2017 – November 2017 TLV320AIC3109-Q1
PRODUCTION DATA.
The TLV320AIC3109-Q1 supports the I2C control protocol using 7-bit addressing and is capable of both standard and fast modes. As illustrated in Figure 28, the minimum timing for each tHD-STA, tSU-STA, and tSU-STO is 0.9 μs for I2C fast mode. The TLV320AIC3109-Q1 responds to the I2C address of 001 1000. I2C is a two-wire, open-drain interface supporting multiple devices and masters on a single bus. Devices on the I2C bus only drive the bus lines low by connecting the lines to ground; the devices never drive the bus lines high. Instead, the bus wires are pulled high by pullup resistors so the bus wires are high when not being driven low by a device. This way two devices cannot conflict; if two devices drive the bus simultaneously, there is no driver contention.
Communication on the I2C bus always takes place between two devices, one acting as the master and the other acting as the slave. Both masters and slaves can read and write, but slaves can only do so under the direction of the master. Some I2C devices can act as masters or slaves, but the TLV320AIC3109-Q1 can only act as a slave device.
An I2C bus consists of two lines, SDA and SCL. SDA carries data; SCL provides the clock. All data are transmitted across the I2C bus in groups of eight bits. To send a bit on the I2C bus, the SDA line is driven to the appropriate level when SCL is low (a low on SDA indicates the bit is zero; a high indicates the bit is one). When the SDA line settles, the SCL line is brought high then low. This pulse on SCL clocks the SDA bit into the receiver shift register.
The I2C bus is bidirectional: the SDA line is used both for transmitting and receiving data. When a master reads from a slave, the slave drives the data line; when a master sends to a slave, the master drives the data line. Under normal circumstances the master drives the clock line.
Most of the time the bus is idle, no communication is taking place, and both lines are high. When communication is taking place, the bus is active. Only master devices can start a communication by causing a START condition on the bus. Normally, the data line is only allowed to change state when the clock line is low. If the data line changes state when the clock line is high, then the data line state is either a START condition or a STOP condition. A START condition is when the clock line is high and the data line goes from high to low. A STOP condition is when the clock line is high and the data line goes from low to high.
After the master issues a START condition, the master sends a byte that indicates which slave device to communicate with. This byte is called the address byte. Each device on an I2C bus has a unique 7-bit address. (Slaves can also have 10-bit addresses; see the I2C specification for details.) The master sends an address in the address byte with a bit indicating whether to read from or write to the slave device.
Every byte transmitted on the I2C bus, address or data, is acknowledged with an acknowledge bit. When a master finishes sending a byte (eight data bits) to a slave, the master stops driving SDA and waits for the slave to acknowledge the byte. The slave acknowledges the byte by pulling SDA low. The master then sends a clock pulse to clock the acknowledge bit. Similarly, when a master finishes reading a byte, the master pulls SDA low to acknowledge this operation to the slave. The master then sends a clock pulse to clock the bit.
A not-acknowledge is performed by simply leaving SDA high during an acknowledge cycle. If a device is not present on the bus and the master attempts to address the device, the master receives a not-acknowledge because no device is present at that address to pull the line low.
When a master finishes communicating with a slave, the master can issue a STOP condition. When a STOP condition is issued, the bus becomes idle again. A master can also issue another START condition. When a START condition is issued when the bus is active, this condition is called a repeated START condition.
The TLV320AIC3109-Q1 also responds to and acknowledges a general call, which consists of the master issuing a command with a slave-address byte of 00h. Figure 29 and Figure 30 show timing diagrams for I2C write and read operations, respectively.
In the case of an I2C register write, if the master does not issue a STOP condition, then the device enters auto-increment mode. So in the next eight clocks, the data on SDA are treated as data for the next incremental register.
Similarly, in the case of an I2C register read, after the device has sent out the 8-bit data from the addressed register, if the master issues an acknowledge, the slave takes over control of the SDA bus and transmits for the next 8 clocks the data of the next incremental register.