int e l 8.4 RUN TRAP OPTION (Version 1.1 Only) Version 1.1 of MCS BASIC-52 permits the user to trap the interpreter in the RUN MODE. This option is evoked by putting a 34H (52D) in external data memory location 5EH (94D). After a 34H (52D) is placed in external data memory location 5EH (94D) the MCS BASIC-52 interpreter will be trapped in the RUN mode forever or until the contents of external data memory location is changed to something other than 34H (52D). If no program is present when a 34H (52D) is placed in location 5EH (94D), MCS BASIC-52 will print the READY message forever and it will be time to RESET the device.
The RUN TRAP option can be employed with the other RESET options to permit the user to execute a program from RAM on a RESET or power-up condition when some type of battery back-up memory scheme is employed. - 102 -