In this paper, we propose a scalable distributed memory system with a low-cost hardware message-passing interface. The proposed interface improves the communication performance between nodes to decrease the overhead synchronization with a receiver reservation technique. The simulation results indicate that the performance is increased by 20% on 4x4 communications. The synthesis result of the proposed MPI indicates that the area was only 4.49% of each computing node. As a result, the proposed system is a useful embedded MPSoCs (Multiprocessor System on a Chip) for its low-cost implementation and scalability.