According to the IEEE 1149.1 Boundary Scan System, every complex system can have more than one boundary-scan-compliant scan port. If each of these scan ports are linked together, then the chances of enhancing the scan capability would definitely increase. In this design, the multiple scan ports are linked together by implementing instructions feed in to the IEEE 1149.1 port. The MSP (Multiple Scan Port) device can be used to link the four local scan ports or it can be completely bypassed. An ENABLE signal is provided, when low, the device outputs are tri-stated so a Lattice ispDOWNLOAD® Cable can be used directly on the secondary chains for in-system programming.