Hi, I defined a RAM address to act as a flag register; ; --- Flags #define NEW_PACKET FLAGS,0 ; New packet received #define NOCV FLAGS,1 ; No CV found #define RDONLY FLAGS,2 ; CV read only #define DCC4BYTE FLAGS,3 ; DCC command 4 bytes #define PWM_DIR FLAGS,4 ;*Direction of travel, 1=Forward 0=Reverse #define CV513Plus FLAGS,5 ;*Signal if second address #define PROG_2X FLAGS,6 ; 2x prog #define RESET_FLG FLAGS,7 ; reset packet Is it possible that i can set or reset during debug one or more of the flags using the stimulus or by other means. Thanks Harry -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist