corsavec:
I found this library GitHub - andresarmento/modbus-arduino: A library that allows your Arduino to communicate via Modbus protocol, acting as a slave (master in development). Supports serial (RS-232, RS-485) and IP via Ethernet (Modbus IP). but it's not working. my sketch is freezing at mb.config(mac, ip);
Dear corsavec!
I think you need to change CS pin in ModbusIP_ENC28J60.h to the same pin what is defined in the UIP library (may if its defined in the uip lib, but why not.... I doesnt use the UIP lib. :P).
#define ENC28J60_CS 8 //Default chip select pin
I use the ethercard library, and andrasemento uses it too in his modbus library.... Another thought, try to use the ethercard library insted the UIP library for the ENC28J60 module.
This CS pin changing helped me to get alive the modbus system.
Robert