Currently the industry moves to smaller process nodes even if the cost for yielding large dies continues to increase, moving to the 5nm and even 3nm nodes. Hence a chiplet-based design has been initiated and quickly gain attention from industry, academia and government agencies. This cutting edge approach became advantageous to break down a large die into smaller chiplets in order to improve yield and binning. In order to exploit this new approach the interconnect fabric connecting the nodes of the entire system should be of high importance to enable the properly distribution of the data. Each individual chiplet may contain its own local Network on Chip (NoC), which operates for intra-chiplet traffic. However the communication over chiplet-based systems is complicated enough, due to various routing algorithms and NoC topologies and an alternative solution is needed. In this paper we introduce an SDNoC(Software Define Network on Chip)-based communication protocol for chiplet-based systems, called MicroLET, which consists of a flexible and modular SDNoC architecture and 3 main phases: Handshake, Network Monitoring, Routing. An implementation of the SDNoC architecture and an evaluation of the proposed routing algorithm compared to the XY and the Odd-Even algorithms within different traffic scenarios is presented. Through the evaluation of the MicroLET protocol, it is proven that it could be a good candidate for the future chiplet-based systems.