A battery-powered, hand-held, calculator employs MOS/LSI calculator circuits to perform arithmetic and financial calculations. Data and commands are input to the calculator from a keyboard having shift key to double the functions of selected keys. A 15-digit, seven-segment light emitting diode (LED) display serves as the output for the calculator. The calculator circuits include a read-only memory circuit in which the algorithms for performing the arithmetic and financial calculations are stored; a control and timing circuit for scanning the keyboard, retaining status information about the condition of the calculator or of an algorithm, and generating the next read-only memory address; and an arithmetic and register circuit containing an adder, a group of working registers, a group of data storage registers forming a stack for roll down operation, and a constant storage register. These circuits are interconnected by a multiple line buss system.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a division of allowed U.S. Pat. application Ser. No. 302,371 entitled "General Purpose Calculator with Capability for Performing Interdisciplinary Business Calculations" filed by France Rode, et al. on Oct. 30, 1972, and now U.S. Pat. No. 3,863,060 and which is hereby incorporated by reference as amended as if fully set forth herein.
A calculator apparatus is provided for computing minimum principal amounts for deposit into demand (passbook) accounts and into term (certificate-of-deposit) accounts paying interest at differing rates. The computed minimum principal amounts not only satisfy the minimum deposit requirements of the term accounts but, when deposited, provide both maximum interest earnings and payments from principal, without interest penalty ordinarily associated with early withdrawals. The apparatus comprises a keyboard, a read-write memory, a logic unit, a printer, and a display unit. The logic unit includes an arithmetic unit having a plurality of data storage registers and a read-only-memory with a stored program. The apparatus computes the minimum principal amounts in accordance with the stored program and in response to entered data.
In a financial calculator, a graphic representation function is provided, and financial values desired for an operator are calculated based upon various input financial data. Also, both the entered data and calculated values are displayed as a graphic representation. In the graphic representation, a display interval of a pattern is determined based upon the number of the display data, and a magnitude of the pattern is determined based on the magnitude of the data value.
A programmable electronic calculator is provided having a manually operable annuity switch with begin- and end-position settings, enabling a user to specify the type of annuity calculation to be performed. When the switch is set to the begin position, the annuity calculation is performed with payments due at the beginning of each payment period; when the switch is set to the end position, the annuity calculation is performed with payments due at the end of each payment period. The annuity calculation is performed under control of a routine stored in a read-only-memory (ROM) of a data processing unit.
A portable electronic financial calculator and planner displays all the variables associated with the financial problem to be calculated on one screen to enable the user to more efficiently input numeric information corresponding to the various variables of the desired financial calculation. To display all the variables in common English terms, the portable financial calculator and planner has separated the financial problems into separate applications which enables this device to display variables distinct to the selected problem. This portable financial calculator and planner includes a display panel having at least eight lines of multi-digit display units. The portable electronic financial calculator and planner also has an input device which allows the operator to input numeric information into the fields corresponding to the known variables of the financial problem by allowing the user to utilize a movable cursor which is capable of moving from field to field. This input device also includes an answer request symbol to allow the user to assign one variable of the financial problem as the unknown variable to be determined. By displaying all the variables on one screen and allowing the user to input numeric information into any field associated with the variables of the financial problem through the use of a cursor, the portable electronic financial calculator and planner allows the user to operate it without extensive training.
