iopadmap - technology mapping of i/o pads (or buffers)

    iopadmap [options] [selection]

Map module inputs/outputs to PAD cells from a library. This pass
can only map to very simple PAD cells. Use 'techmap' to further map
the resulting cells to more sophisticated PAD cells.

    -inpad <celltype> <portname>[:<portname>]
        Map module input ports to the given cell type with the
        given output port name. if a 2nd portname is given, the
        signal is passed through the pad call, using the 2nd
        portname as the port facing the module port.

    -outpad <celltype> <portname>[:<portname>]
    -inoutpad <celltype> <portname>[:<portname>]
        Similar to -inpad, but for output and inout ports.

    -toutpad <celltype> <portname>:<portname>[:<portname>]
        Merges $_TBUF_ cells into the output pad cell. This takes precedence
        over the other -outpad cell. The first portname is the enable input
        of the tristate driver.

    -tinoutpad <celltype> <portname>:<portname>:<portname>[:<portname>]
        Merges $_TBUF_ cells into the inout pad cell. This takes precedence
        over the other -inoutpad cell. The first portname is the enable input
        of the tristate driver and the 2nd portname is the internal output
        buffering the external signal.

    -widthparam <param_name>
        Use the specified parameter name to set the port width.

    -nameparam <param_name>
        Use the specified parameter to set the port name.

    -bits
        create individual bit-wide buffers even for ports that
        are wider. (the default behavior is to create word-wide
        buffers using -widthparam to set the word size on the cell.)

Tristate PADS (-toutpad, -tinoutpad) always operate in -bits mode.