AR# 3083: 4.1i XC4000e MAP - "ERROR - No more route-throughs available"
4.1i XC4000e MAP - "ERROR - No more route-throughs available"
Keywords: MAP, XC4000e, no, more, route-throughs
General Description: The following error message is issued:
"ERROR - No more route-throughs available."
This misleading error message from 4000e MAP is an indication that a BUFGP has non-clock loads that it cannot reach without inserting a route-through.
This problem occurs when the non-clock load is mapped to an H-LUT, and the BUFGP is located on one of the left side sites (that can only reach F and G LUTs directly). The router is forced to use an F or G route-through to get to a C pin, then to the H-LUT. Therefore, the reference to no route-throughs being available is incorrect.
The skew introduced by this problem can be avoided by FMAPing the non-clock loads so that they are not mapped to an H-LUT.