PCA9661B device is "Not recommended for new designs", please use the replacement part PCA9665APW
The PCA9661 is an advanced single mode I²C-bus controller. It is
a fourth generation bus controller designed for data intensive I²C-bus
data transfers. It has one I²C-bus channel with data rates up to 1
Mbits/s using the Fast-mode Plus (Fm+) open-drain topology. The serial
channel has a generous 4352 byte data buffer which makes the PCA9661 the
ideal companion to any CPU that needs to transmit and receive large amounts
of serial data with minimal interruptions.
The PCA9661 is a 8-bit parallel-bus to I²C-bus protocol converter. It
can be configured to communicate with up to 64 followers in one serial
sequence with no intervention from the CPU. The controller also has a
sequence loop control feature that allows it to automatically retransmit a
Its onboard oscillator and PLL allow the controller to generate the clocks
for the I²C-bus and for the interval timer used in sequence looping.
This feature greatly reduces CPU overhead when data refresh is required in
fault tolerant applications.
An external trigger input allows data synchronization with external events.
The trigger signal controls the rate at which a stored sequence is
re-transmitted over the I²C-bus.
Error reporting is handled at the transaction level, channel level, and
controller level. A simple interrupt tree and interrupt masks allow further
customization of interrupt management.
The controller parallel bus interface runs at 3.3 V and the I²C-bus
I/Os logic levels are referenced to a dedicated VDD(IO)
input pin with a range of 3.0 V to 5.5 V.