Determining operating state of a remote device and corresponding host system

摘要

Method for determining status information of remote devices performed on host system connected via bus system comprising two signal lines (clock SCL, data SDA). Clock line is terminated with pull-up resistor RHC1 on host and switchable resistor on remote device; data line is terminated with pull-down resistor RHD0 on host and pull-up resistor RRD1 on device. The method comprises the steps: activating sensing phase; sensing the two terminated signal lines (Clk SCL, Dat SDA) during sensing phase; determining operating state of the remote device based on sensing result; wherein four different operating states are detectable. First state represents remote device plugged, powered, and initialised (clock signal line high, data line high); second state is for unplugged device (high, low); third state is for plugged but not powered device (low, low); fourth state is for plugged, powered, but not initialised state (low, high). The bus can be low-pin count bus (I2C).