I2C bus with new master selector device
PHILIPS Electronics has released a new two to one I2C master selector optimised for selecting one of two I2C master devices that connect to a shared resource in products ranging from MP3 players to servers in computing, communication and networking applications.
The PCA9541 enables two separate I2C masters to have access to the same slave device without having to communicate with each other, simplifying design complexity and cost by using a single device to replace the multiple chips previously used for this I2C multiple master application.
The PCA9541 has reduced component count by a factor of three and cost by a factor of four in comparison with multiple master I2C applications that used discrete components. The new I2C master selector will help make the next generation UltraSPARC server more reliable than its predecessors.
For the server market, having multiple masters or redundant I2C buses fulfils the server's need for reliability in the event that one master fails or its controller card is removed for maintenance. The PCA9541 also allows two non-multiple capable masters to share a common resource such as a card maintenance history EEPROM.
The device can also be used as a gatekeeper multiplexer which prevents address conflicts when additional identically addressed devices are connected into larger architectures since only one slave device is allowed to speak with the master at any given time.
The PCA9541 features a hardware pin reset function that returns the master selector to the default state, enabling continued communication with upstream slave devices without having to cycle power through critical equipment. It can also function as a voltage level translator between 1.8V, 2.5V, 3.3V and 5V on different buses.
The PCA9541 is offered in three versions and is available in HVQFN packages, and 20-pin SO and TSSOP packages.
The PCA9541/01, is suitable for server applications and requires no set up for communication with downstream I2C slave devices on Bus 0.
The PCA9541/02, for hot swap in telecom applications with potential traffic on the I2C bus, does not connect Bus 0 until the bus is idle
The PCA9541/03, for general-purpose applications, defaults to off with neither Bus 0 or Bus 1 connected at start up.
15-Dec-2003