model <- function(t, state, parms) {
  with(as.list(c(state,parms)), {
    dR <- -c*R*N
    dN <- -d*N/(h+R)
    return(list(c(dR, dN)))  
  }) 
}  

p <- c(c=0.1,d=0.005,h=0)
s <- c(R=1,N=0.01)

after <- "if(t %% 30==0){cat(state[2],\"\n\");state[1]<-1;state[2]<-state[2]*10}"
run(300,after=after)