INPUT_PULLUP means "internally pull-up open drain"? DA14580's pin mode

Hi,

The port pin's INPUT_PULLUP means "internally pull-up open drain" or not ?
For clarify, The circuit image "pull-up open drain" is shown this ->http://cfile6。uf.tistory.com/original/2249FB42558E3DDF351CD1(in this image the pullup resistor is external)

If the DA14580 port pin's INPUT_PULLUP is "internally pull- up open drain" , how can I "Drive Low"?
"Drive Low" means the switching to ground in above image.