Difference between push-pull output and drain-Open output

Push-pull output: the internal force pulls up, the irrigation and the pulling power streams all reach 20mA, and the external force pulls off the leak: all internal pulls are disconnected, if you want to use,Must be pulled externally. In this case, the driver capability is completely determined by the designer. For example, the P0 port of 8051. Special case: If this port is used as an Active Directory, do not add external pull-up resistor.

Difference between push-pull output and drain-Open output