JAJSN80E August 2009 – May 2022 TCA9535
The TCA9535 has a standard bidirectional I2C interface that is controlled by a controller device in order to be configured or read the status of this device. Each target on the I2C bus has a specific device address to differentiate between other target devices that are on the same I2C bus. Many target devices require configuration upon startup to set the behavior of the device. This is typically done when the controller accesses internal register maps of the target, which have unique register addresses. A device can have one or multiple registers where data is stored, written, or read. For more information see Understanding the I2C Bus application report, SLVA704.
The physical I2C interface consists of the serial clock (SCL) and serial data (SDA) lines. Both SDA and SCL lines must be connected to VCC through a pull-up resistor. The size of the pull-up resistor is determined by the amount of capacitance on the I2C lines. For further details, see I2C Pull-up Resistor Calculation application report, SLVA689. Data transfer may be initiated only when the bus is idle. A bus is considered idle if both SDA and SCL lines are high after a STOP condition. See Table 7-1.
Table 7-1 shows the interface definition.
|7 (MSB)||6||5||4||3||2||1||0 (LSB)|
|I2C target address||L||H||L||L||A2||A1||A0||R/ W|
|P0x I/O data bus||P07||P06||P05||P04||P03||P02||P01||P00|
|P1x I/O data bus||P17||P16||P15||P14||P13||P12||P11||P10|