Electronic checkbook
CROSS REFERENCES 
     U.S. Pat. Nos. 4,075,702 issued in February, 1978 refers to a calculator used in combination with a checkbook. These calculators serve multiple purposes such as division, multiplication, addition, square roots, subtraction, etc. and in no way differ from other calculators for other purposes. In contrast, the electronic checkbook is a dedicated microprocessor which will maintain a checking account balance and store that balance on a day to day basis, even when the machine is not in use, unless there is a failure of the physical components. 
     DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION. 
     This invention relates to an electronic checkbook for providing a means to facilitate the computation, maintenance, and storage of a checking account balance. Manually adding deposits and subtracting check amounts from a checking account balance is a time consuming nuisance, particularly when shopping or paying bills. The possibility exists that many individuals will write out several checks without balancing their checkbook. This results in a possible unknown immediate balance of the checking account of the user of a regular checkbook. A device has been developed in the past which involves the incorporation of a calculator along with a checkbook in a folder. These calculators are multipurpose devices, i.e. the registers are shared with multiplying, dividing, etc. (See U.S. Pat. No. 4,075,702, February, 1978). Inherently these devices are composed of potentially unnecessary complexity of function for maintaining checking account balances. They do not support the sequence of a checking account. They are merely useful tools. The electronic checkbook is dedicated to the problem of checking account balances and maintains the continuity of the process. 
     The present invention relates to an electronic checkbook which can be made inexpensively and produced in a very compact portable package. It is designed specifically for the computation and storage of checking account balances and will both store the balance of the account even when the machine is not in use as well as enforce portions of the computational sequence. The embodiment of the device is of such a nature that when the unit is not in use, the contents of memory are absolutely preserved, short of some failure of the physical components. In the initial embodiment, the components used require that the battery power does not fail or be interrupted in order to maintain the integrity of the stored contents of memory. Other components that are presently available are non-volatile in their memory characteristics. Examples are magnetic ferrite core, electronically alterable integrated circuits, and various film technologies, to list a few. The concept of storing the required memory as a normal portion of the inactive operating cycle of a device of this type, is not predicated on any of these specified techniques of memory and they are mentioned only to illustrate less optimum choices which are presently available, although any other choice might be favorable at another time. Other objects and purposes of the invention are clarified by the following detailed description of the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a perspective view of the interior of the folder containing the electronic checkbook. 
     FIG. 2 illustrates a front view of the character display. 
     FIG. 3 illustrates the dedicated microprocessing unit. 
     FIG. 4 is a switch interconnection diagram relating to FIG. 3. 
     FIG. 5 illustrates a schematic of the electronic circuitry of the electronic checkbook. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Reference is now made to FIG. 1 which shows a perspective view of the interior of the folder 16 containing the electronic checkbook. The lower portion of the folder 16 contains standard size checks 18 bound together with checking account deposit tickets 18. On the right side of the upper portion of FIG. 1 are check stubs 20 possessing numbers corresponding to the standard checks located in the lower portion of the folder and functioning as a place where the user could manually record the amount of the check written, who it was written to, and what is was written for. The stub also provides a space where the user could make a written record of his balance, deposits, and the amounts of the checks he has written. The left hand side of the upper portion of the checkbook contains a view of the panel 22 of the electronic device. As can be seen in FIG. 1, the electronic checkbook can be made to be compact, portable, and operate from internal battery source. The keyboard, indicated generally as 24, is composed of ten numerical keys, a clear key, a decimal point key, plus a number of function keys. Following is an explanation of how a user of the electronic checkbook would operate the device using both the keyboard and function keys. 
     1. When the battery is installed, all registers will reset to ZERO balance. 
     2. If by some sequence you find you have a wrong balance, use the following sequence to clear all registers: (A) Move the Start-Stop switch 26 to &#34;START.&#34; (B) Depress the &#34;CLEAR&#34; button 30. (C) Depress the &#34;REMOVE PROTECT&#34; button 32. (D) Depress the &#34;POST BALANCE&#34; button 34. (E) Move the Start-Stop switch 26 to &#34;STOP.&#34; (F) The balance will now be set at zero. 
     3. 
     A. To make a deposit or a series of deposits, use the following sequence: (1) Move the Start-Stop switch 26 to &#34;START.&#34; Your balance will now appear in the display 42. (2) Press the &#34;DEPOSIT&#34; button 38. (3) Key in the deposit amount on the keyboard 24. (4) Press the &#34;TRIAL BALANCE&#34; button 40 for each deposit. (5) To store the new balance, press the &#34;REMOVE PROTECT&#34; button 32 and then the &#34;POST BALANCE&#34; button 34. 
     B. To see how many checks you will be able to draw against your present balance, perform the following sequence: 
     (1) Move the Start-Stop switch 26 to &#34;START.&#34; Your balance will show on the display 42. (2) Press the &#34;CHECK&#34; button 36. 
     (3) Key in the amount of the check on the keyboard 24. 
     (4) Press the &#34;TRIAL BALANCE&#34; button 40 for each check. 
     Each time you reach a trial balance, the remainder will update. As long as you do not strike the last two keys (REMOVE PROTECT 32, POST BALANCE 34) to post the balance, you will not alter the stored balance. When you are finished, move the Start-Stop switch 26 to &#34;STOP.&#34; The balance will be as it had been before you started. When you go back to the &#34;START&#34; position, the balance you stored will appear in the display 42. It should be noted that the display 42 is a register. Its contents are constantly displayed on the ditigal display except when a key is depressed or when the Start-Stop switch 26 is on &#34;STOP.&#34; 
     4 When you are prepared to enter your trial balance as your new balance, perform the following operations. 
     (a) Push the button labled &#34;X&#34; 44. This will cause the protective cover 46 located over the &#34;REMOVE PROTECT&#34; 32 and &#34;POST BALANCE&#34; 34 buttons to spring open. After the protective cover has opened, press &#34;REMOVE PROTECT&#34; 32 and then &#34;POST BALANCE&#34; 34. Do not press &#34;POST BALANCE&#34; 34 more than once as this will cause an error. If you think it might be wrong simply press &#34;REMOVE PROTECT&#34; 32 again and then press &#34;POST BALANCE&#34; 34 after you have released &#34;REMOVE PROTECT&#34; 32. Whatever balance is showing on the display 42 when you enter the sequence &#34;REMOVE PROTECT&#34; 32 &#34;POST BALANCE&#34; 34, will then be stored in the balance register. 
     5 When you are finished, if you want to check that the correct balance is being saved, move the Start-Stop switch 26 to &#34;STOP.&#34; &#34;START&#34; again and the amount stored in the register 42 will be displayed. 
     6 If your balance is an even number of dollars or dimes, the balance will be displayed without the end zeros. This will not alter the accuracy of your electronic checkbook. 
     The digital display 42 may consist of either an L.E.D. (light emitting diode) or L.C.D. (liquid crystal display) or any device capable of producing such a display. The stored balance of the checkbook would be displayed here when the machine is activated. Individual check or deposit entries would also appear here as they are entered into the machine. New balances, resulting from adding deposits or subtracting checks after pressing the &#34;TRIAL BALANCE&#34; button 40 would also appear here. 
     A spring 48 opens the protective cover 46 located over the &#34;REMOVE PROTECT&#34; 32 and &#34;POST BALANCE&#34; 34 buttons. The function of the protective cover 46 is to keep the &#34;REMOVE PROTECT&#34; 32 and &#34;POST BALANCE&#34; 34 buttons from being accidentally depressed. 
     FIGS. 2, 3, 4, and 5 refer to the description of the embodiment of the electronic checkbook function which follows. Before describing such function, several items in the aforementioned drawings are referred to. FIG. 2 represents a front view of the character display showing the wiring relationship. All connections labeled &#34;J&#34; 50 in FIG. 2 are typical of eight corresponding character locations. &#34;J&#34; 50 illustrates the portion of that character that is connected to all eight. Reference is also made to the substrate connection 52 to select the character. The dedicated microprocessor 54 is depicted in FIG. 3. FIG. 4 represents the switch closure table and FIG. 5 represents a schematic of the electronic circuitry of the device connected to internal battery source 56. 
     The detailed description of the embodiment of the electronic checkbook function is referred to as follows. The data collection, and logical processing of the electronic checkbook may all be accomplished on a single chip computer. The computer may be a fixed program type, sometimes called a calculator chip. The program sequentially tests for a closure to occur between pins 5, 6, 7, or 8 of the package, and pins 10, 12, 13, 15, 16, or 17 of the package. When such a closure is detected, the chip processing halts until the closure ceases. Upon termination of the closure, the processor executes an appropriate response. Of the 24 possible selections which may be achieved by connecting one of the group of four to any one of the group of six, each has a different significance. Table 1 shows the specific responses for each of the closures used. 
     
                       TABLE 1                                                     
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First Second                                                              
Group Group                                                               
Pin   Pin     Designation     Response                                    
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5     10      REMOVE PROTECT  set memory to ZERO                          
6     10      START           display memory                              
8     10      POST BALANCE    add display to                              
                              memory                                      
5     13      7               enter 7                                     
6     13      8               enter 8                                     
7     13      9               enter 9                                     
5     15      4               enter 4                                     
6     15      5               enter 5                                     
7     15      6               enter 6                                     
5     16      1               enter 1                                     
6     16      2               enter 2                                     
7     16      3               enter 3                                     
6     17      0               enter 0                                     
5     12      C               clear display                               
7     17      .               enter decimal                               
8     15      CHECK           subtract next entry                         
8     16      DEPOSIT         add next entry                              
8     17      TRIAL BALANCE   tally last                                  
                              instruction                                 
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