In this paper we present an extension to the co-design approach based on LO
TOS presented in Fourth International Workshop on Hardware-Software Go-Desi
gn, 1996. In this new Version we add a prototyping stage to our design flow
, that allows to validate the design at the implementation level. We presen
t the complete approach, stressing. the prototyping stage after partitionin
g. An example of an Ethernet bridge serves us to illustrate our approach an
d present some results.