NXP Fast-mode Plus parallel bus to I2C-bus controller PCA9665 Key features 4 Converts parallel-bus to I2C-bus protocol 4 Master and slave functions 4 Multi-master capability 4 Capable of 1 Mbps and 30-mA SCL/ SDA 4 68-byte data buffer option 4 I2C-bus General Call option 4 Software reset capability on parallel bus Applications 4 Adding one or many I2C-bus ports to a microcontroller or a microprocessor 4 Reducing the number of traces on the PCB 4 Increasing I2C-bus throughput 4 Putting more I2C devices on the bus 4 Off-loading I2C-bus processing The NXP PCA9665 allows the 8-bit parallel bus system of a microcontroller or microprocessor to communicate bidirectionally with the I2C-bus. The device has a 68-byte buffer and is an upgraded version of the PCA9564, making it capable of higher speeds and able to drive bigger I2C-buses. There are two operating modes - byte and multiple-byte. In byte mode, the PCA9665 is comparable to the PCA9564 and performs parallel-to-serial and serial-to-parallel conversions one byte at a time. In multiple-byte (buffered) mode, the PCA9665 can send or receive up to 68 bytes at once. This significantly decreases the number of interrupts handled by the processor, so the processor can handle other tasks while the PCA9665 interacts with the I2C-bus. In both operating modes, feedback on the task and operation execution is performed through the active low interrupt output (INT) or by polling the PCA9665 status register. All the tasks related to the I2C-bus, including protocol, arbitration, bus errors, and timing, are handled without requiring an external timing element. The PCA9665 supports I2C General Call capability, and can be configured to respond to the General Call command if the application requires it. A Software Reset scheme on the parallel bus lets resets take place without the use of an additional pin, and an internal oscillator reduces the number of external components.

The device can operate in Standard, Fast-mode and Fast-mode Plus, and is compatible with the SMBus protocol. The operating supply voltage is 2.3 to 3.6 V and all the I/O are tolerant to 5 V. The I2C-bus clock frequency is 0 to 1 MHz, and the SDA and SCL outputs are capable of driving 30 mA. The operating temperature is -40 to +85 °C. ESD protection exceeds 2,000 V HBM per JESD22-A114, 200 V MM per JESD22-A115, and 1,000 V CDM per JESD22-C101. Latch-up testing, performed in accordance with JEDEC Standard JESD78, exceeds 100 mA. For more information visit www.nxp.com/i2clogic DIRECT REGISTERS I2CDAT...