Here is a more detailed example of an industrial gateway application. On the left, the dual CAN 2.0B modules make the STM32 connectivity line a turnkey solution to implement a CAN gateway. On the right is an Ethernet connectivity circuit, with an external PHY connected to the STM32 using either an MII or RMII interface. The IEEE 1588 precision time protocol hardware support provides clock synchronization over the network of 100µS or less. This feature is particularly useful in industrial applications where two or more nodes must act on the same process in perfect synchronization. The STM32’s PLL Block generates the clock for the PHY with a frequency of either 25 or 50MHz. Therefore, a single 25MHz quartz can clock the STM32 core, its peripherals and the external PHY.