Self-programing memory tuning system

#This invention relates to that described and claimed in application Ser. No. 932,141 filed Aug. 9, 1978 and assigned to the same assignee as this application.

#The forementioned application describes a microprocessor control system for affecting channel selection and function level adjustments. The system uses an electrically alterable ROM to store television broadcast station or channel information which is retrieved by the microprocessor and converted by a digital-to-analog converter into voltages for use by a varactor tuner to tune in channels on a television receiver. Should the electrically alterable ROM lose some or all of the channel information stored in it, a repairman would have to reinsert that information manually in order for the receiver to be able to be tuned to the channels corresponding to the lost information. Alternatively the microprocessor could have stored in its internal ROMs all of the channel information which was also stored in the electrically alterable ROM. Neither of these alternatives is acceptable. The former because it would require the repairman to expend an inordinate amount of time in order to insert this information manually into the ROM. The latter because the duplication would use up too much of the capacity of the internal ROMs.

#In accordance with the invention, a program and selective channel information is stored in the microprocessor by which approximate channel information for the electrically alterable ROM can be reconstructed by the microprocessor and restored to the electrically alterable ROM automatically. This relieves the repairman of the need of having to do all of this manually. It also uses much less capacity of the internal ROMs than would be used if all of the channel information for the electrically alterable ROM was also to be stored in the internal ROMs.

#FIG. 1 is a schematic drawing of the apparatus by which the invention is practiced.

#FIG. 2 is a flow diagram of the program for practicing the invention.

#FIG. 1 shows apparatus which is also shown in FIG. 2 of the forementioned application Ser. No. 932,141. Rather than duplicate the description of that apparatus contained therein that application is incorporated entirely herein by reference.

#From the flow chart of FIG. 2 and the program which follows as listed, a skilled programmer could duplicate the constructed embodiment of the invention and practice it in accordance with the preferred manner. In the constructed embodiment, there was stored in the internal ROMs of microprocessor 25 binary information identifying the voltage levels required across the varactor tuner in order to tune to each of the VHF channels 2 through 13. The following table shows the voltage levels for each of these channels for the particular varactors employed in the tuner of the constructed embodiment.

#______________________________________ Tuning Voltage Channel Volts ______________________________________ VHF 2 4.5 3 6.8 4 9.3 5 14.7 6 22.0 7 11.0 8 12.1 9 13.1 10 14.4 11 15.8 12 18.0 13 22.0 UHF 10 1.5 20 3.8 30 6.2 40 9.0 50 11.8 60 14.2 70 17.1 80 22.0 ______________________________________