ZHCSD68H July 2014 – April 2021 LSF0204 , LSF0204D
PRODUCTION DATA
The controller output driver may be push-pull or open-drain (pull-up resistors may be required) and the peripheral device output can be push-pull or open-drain (pull-up resistors are required to pull the Bn outputs to Vpu).
However, if either output is push-pull, data must be unidirectional or the outputs must be 3-state and be controlled by some direction-control mechanism to prevent HIGH-to-LOW contentions in either direction. If both outputs are open-drain, no direction control is needed.
In Figure 10-1, the reference supply voltage (Vref_A) is connected to the processor core power supply voltage. When Vref_B is connected through to a 3.3 V Vpu power supply, and Vref_A is set 1.0V. The output of A3 and B4 has a maximum output voltage equal to Vref_A, and the bidirectional interface (Ch1/2, MDIO) has a maximum output voltage equal to Vpu.