It is a Dinar from Serbia similar to the one below:
Serbia: Stefan Uroš V (1355-71) AR Dinar (Dobrinic-8.1.2; Dimitrijevic-39)
Obv: Stefan enthroned facing, holding cross-tipped sceptre and akakia; Legend on either side - UШb - Чb
Rev: Helmet facing left with crest; Legend around - VROSIVSI MPERATOR
I suggest you download Opis Jugoslavenskih Novaca by Ljubića to determine your actual type: