Diplomsko delo opisuje ponovni razvoj M-Bus dela komunikacijskega modula za pametne števce družine AM500. Natančneje, gre za izhodni in merilni del manjšega M-Bus gospodarja, ki pošilja signale naprej na glavno tiskano vezje števca. V prvem poglavju je predstavljen pametni števec in namen komunikacije v njem. V drugem poglavju je opisana zgodovina komunikacije M-Bus, osnove serijske komunikacije, model OSI in kako je uporabljen pri M-Bus-u ter opis delovanja komunikacije M-Bus. Nato je opisan razvoj komunikacijskega modula, dane zahteve, opis napetostnega in tokovnega dela, opis mikrokrmilnika ATtiny10 ter opis risanja tiskanega vezja s programom Altium Designer. V naslednjem poglavju je opisana programska koda za mikroprocesor. Na koncu so predstavljeni rezultati testiranja.This thesis describes the development of M-Bus communication module for AM500 family of smart meters. More specifically, it describes the output and measurement part of M-Bus mini-master, which sends data to the main PCB of a smart meter. In the first chapter, smart meter and the purpose of its communications is presented. The second chapter describes the beginnings of M-Bus communication and its function, the basics of serial communication, the OSI model and how it applies to M-Bus. Then, the development and the requirements of M-bus module are described. This includes the output voltage part and the measurement of current part, which also describes the microcontroller ATtiny10. This chapter also includes the design of the printed circuit board, which was drawn using Altium Designer. This is followed by a description of the program code for the microcontroller. Finally, results of module testing are presented