Abstract:
An electronic parking meter operating system comprising a microprocessor mounted within a meter housing, a semiconductor disc memory having at least 8K memory bytes, and a plurality of programs stored in the disc memory. A meter event such as the deposit of a coin will cause interrogation of an auxiliary program module map to determine if one of the plurality of programs should be used to substitute for or augment a program which is provided in the microprocessor to normally carry out meter functions. If substitution or augmentation is called for, an address table in the memory disc is used to locate the selected program, to load it into the microprocessor, and to execute the program.

Description:
This invention relates to parking meters having electronic components. Such meters typically include upper and lower housings usually containing a cash box for coins and tokens deposited in the meter. The upper housing typically incorporates a display window through which a digital display can be observed. 
     The digital display may be a component of a mechanism which is receivable within the upper housing and removable therefrom. This mechanism will also incorporate a coin slot and, in more recent times, a card slot for receiving a debit card or the like. 
     The mechanism of a typical electronic parking meter also incorporates a power source such as a battery. A microprocessor programmed to operate the digital display in accordance with time purchased, time remaining, and time expired conditions is contained in the mechanism. Other electronic components, operating in conjunction with the microprocessor, may perform functions such as coin and card validation, recording of meter activity, and vehicle presence sensing. Communication may also be established by virtue of plug-in or infrared capability to perform such functions as retrieving information on meter activity which has been stored by the mechanism, and to alter the cost/time rate of a mechanism. 
     As described in the jointly-owned application Ser. No. 08/844,159, filed Apr. 18, 1997 entitled &#34;Parking Meter With Peripheral Functions&#34;, it is desirable to increase the versatility of parking meters. In particular, one or more peripheral devices may be associated with the meter for performing functions related to parking and also unrelated functions such as, for example, controlling tennis court lights. 
     SUMMARY OF THE INVENTION 
     This invention relates to electronic parking meters which employ microprocessor control. In particular the invention involves the electronic architecture of a meter comprising a ROM based microcomputer device containing parking meter operating system software with input/output resources to manage normal meter functions such as a liquid crystal display, coin acceptance, rate computation, smart card interface, etc. The system also includes a separate semiconductor disc memory. The system can support an extremely large memory, for example, up to 274 billion bytes of semiconductor disk memory but may also involve much lower capacities such as 8K or 32K bytes. 
     The semiconductor disc memory is used for storage of meter program parameters, for example, those dealing with time to be paid for the deposit of a quarter. In addition, executable programs for extension of the meter functionality are stored in this disc memory. Such an extended function may comprise, for example, using the meter to turn on tennis court lights. 
     The operating system software thus supports auxiliary programs stored on the semiconductor disc. These programs can: 
     1. Replace the meter&#39;s normal functions for coin acceptance, rate processing, display management and communications, or, 
     2. Augment normal program functions. In this capacity the system will initiate a function other than a normal meter function either before or after performing a normal function. 
     The semiconductor disc memory of the system preferably is divided into sectors with certain sectors containing pre-assigned files used in system operation. In a preferred embodiment, a first sector contains a directory and audit file. The last three sectors of the memory are reserved for special events, coin acceptance, and a &#34;scratch pad&#34; for maintenance logging, etc. 
     Rates and rate schedules are stacked on top of the last three sectors. Sectors between these pre-assigned sectors are then available for auxiliary program files. 
     By building the disc memory from the top and from the bottom, addition of auxiliary programs and/or extension of the programmable parameter files is achieved without total system reconfiguration thereby minimizing reprogramming communication time. 
     In addition, with a semiconductor disc memory system with binary addressing, the first and last file locations are always known, no matter how large the memory. Thus, the first location will always have all &#34;0&#34; bits as the address and the last address will always be made up of all &#34;1&#34; bits. The first and last locations of the system will always operate the same way with discs of any size, and all other files can then be referenced either to the first or last sectors. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a parking meter of the type adaptable to the concepts of this invention; 
     FIG. 2 is a schematic illustration of an electronic system characterized by the features of this invention; and, FIG. 3 is a diagrammatic illustration of an operating sequence. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a parking meter 10 consisting of an upper housing 12 and lower housing 14. The upper housing defines display window 16 and a payment means 18, which may accommodate coins, tokens, debit cards, and the like, is located on one side of the housing. The lower housing is designed to hold a cash box and security door 20 is provided for access thereto. 
     The top 22 of upper housing 12 is removable to permit installation of a mechanism including the payment means 18 and also including digital display which is visible through window 16. The digital display, infrared communication functions, and other standard meter functions, are controlled by a microprocessor mounted on a PC board located in the mechanism interior. &#34;Biscuit&#34; 24 may be installed in between the upper and lower housings, and may serve as a housing for peripheral meter functions such as a vehicle sensor. 
     The electronic architecture of the invention involves the use of a ROM based microcomputer or microprocessor 30 shown in FIG. 2. This microprocessor which may be, for example, a Mitsubishi M38275 type, includes input/output connections and these are employed in part to achieve normal meter functions such as coin sensing, card verification, time display, etc. Additional connections (J3-1 to J3-4) may be used for a modular jack for communication with peripheral devices as described in the aforementioned copending application. 
     A semiconductor disc memory 32 includes input/output connections for interfacing with microprocessor 30. This memory could be the same as used in typical products, such as a Xicor 28C64/256. The memory capacity could be 8K bytes or lower up to 274 billion bytes or even higher. The larger memory capacity permits the storage of numerous programs which can then be implemented in the course of the parking meter usage. 
     Storage of meter program parameters is among these possibilities. These may comprise, for example, variations in the amount of time to be given for a specific payment. In addition, the disc memory may store executable programs for extension of the meter functions, for example, to turn on lights when a coin is accepted. 
     The invention employs meter operating system software comprising a program stored in the microprocessor 30. This software provides support for the programs stored in the memory disc 32 when extended functions are called for. As noted, these auxiliary programs can do two things: 
     1. Replace normal program functions. Thus, without the programs on the memory disc, the meter will function normally for coin acceptance, rate processing, display management and communication. The memory disc makes available additional programs for carrying out these functions. Alternatively, the replacement programs may be independent of normal meter functions and may comprise, for example, those intended to carry out peripheral functions using connections J3-1 to J3-4 such as vehicle presence sensing, data interchange, power dispensing control and other functions as described in the aforementioned copending application. 
     2. Augment normal program function. In this case, the memory disc makes available programs which can be executed before or after the normal meter function has taken place. 
     At each significant event in meter operation, the operating system interrogates an auxiliary program module map which contains information regarding whether there is a replacement or augmentation program for a given meter function. If not, the meter functions normally. If a replacement or augmentation program exists it is loaded from the semiconductor disc and executed in place of or in addition to the normal function. 
     The &#34;flow diagram&#34; of FIG. 3 illustrates an example of meter operation using the system of the invention. The auxiliary program module map is consulted whenever a significant event in the meter operation occurs. Such an event could involve, for example, the insertion of a card or coin, or a communication from some external source such as a handheld infrared device or a vehicle presence sensor. If the bit in the auxiliary program module map associated with the event is not set (=0) then the normal software for response to the event is executed on microprocessor 30. 
     If the bit associated with the event is set (=1) in the auxiliary program module map then the memory disc is accesssed to select the correct program for execution in response to the event. 
     The selected program is loaded into microprocessor 30 and executed. 
     Once an auxiliary program is running, the operating system software contained in the ROM within microprocessor 30, supports program execution with access to an arithmetic package, i/o drivers, a communications package, memory management functions, e.g., directory, load, save, etc., and execution management functions, e.g., chaining to an extension of the auxiliary program and calling of auxiliary subroutines. 
     The basic unit of semiconductor disc memory which is allocated is 256 bytes long (a sector). Certain sectors of the disc contain pre-assigned files used in system operation. 
     The first sector contains the directory and audit file. The last three sectors are reserved for special events, coin acceptance and global control parameters, and a scratch pad for maintenance logging, etc. Rates and rate schedules are stacked on top of the last three sectors with the number of sectors allocated for each being dependent on the system requirements. Auxiliary program files are added after the directory and may extend up to the rate schedule. The following table depicts the disk structure (where rl is rate file length and sl is schedule file length). 
     
         ______________________________________Sector       Content______________________________________1            Directory &amp; Audit2 to last-rl-sl-3        Replacement/augmentation program fileslast -2-rl-sl        Rate scheduleslast -2-rl   Rateslast-2       Special Eventslast-1       Coin and global control parameterlast         Scratch pad______________________________________ 
    
     The building of programs down from the top of the disk and programmable parameters up from the bottom permits addition of auxiliary programs and/or extension of the programmable parameter files without total system reconfiguration. This is important in minimizing reprogramming communication time. 
     Further, for a semiconductor disk memory system with binary addressing the first (directory) and last (scratch) locations are always known absolutely, independent of the size of the memory. The first location is all address bits =0 and the last is all address bits =1. Since in the disk structure above all files are referenced either to the first or last locations the system operates with different size semiconductor disk memories completely transparently. 
     The structure of the directory for operating system management is similar to the overall file structure building from the top with auxiliary program related data and from the bottom with parameter related data. 
     auxiliary program module bit map: bytes 1-16 
     auxiliary program file address table: bytes 17-122 
     last program file address: 123 
     extra parameter file address: 124 
     rate schedule file address: byte 125 
     rate file address: byte 126 
     directory sanity check: bytes 127-128 
     The auxiliary program module bit map has a single bit assigned to each major function of the parking meter. If a bit associated with a particular meter function is 0 then the function is performed normally. If the bit is a 1, then the operating system refers to the auxiliary program file address table, obtains the disk address for the associated auxiliary program, loads the program and executes the program. 
     The last program file address locates a sector beyond the end of system auxiliary program files so that if an auxiliary program is to build a database on the disk, this sector is selected avoiding overwriting of program files. The extra parameter file address locates an optional sector in which programmable parameters to be used by auxiliary programs may be stored. The file addresses for rates and rate schedules occupy the last two usable entries in the directory. 
     The following is a listing of auxiliary program module bit map definitions and auxiliary program file address indices which may be used in the operating system for auxiliary program management. 
     background auxiliary programs 
     1. each half second replacement 
     2. flag display replacement 
     3. lcd display replacement 
     4. lcd driver replacement 
     5. real time schedule replacement 
     6. real time schedule augmentation 
     7. expire time replacement 
     8. expire time augmentation 
     coin processing auxiliary programs 
     1. coin preamble augmentation 
     2. coin acquisition replacement 
     3. coin acquisition augmentation 
     4. coin evaluation replacement 
     5. coin accept augmentation 
     6. coin reject augmentation 
     rate processing auxiliary programs 
     1. rate preamble augmentation 
     2. split rate replacement 
     3. split rate augmentation 
     4. deferred time and time left replacement 
     5. deferred time augmentation 
     6. rate process exit augmentation 
     infrared communications auxiliary programs 
     1. infrared communications preamble augmentation 
     2. extended infrared communications functions augmentation 
     3. infrared communications exit augmentation 
     4. communications security process replacement 
     key and card auxiliary programs 
     1. key and card preamble augmentation 
     2. key input/output process replacement 
     3. key and card accept augmentation 
     4. key and card reject augmentation 
     memory card auxiliary programs 
     1. memory card input/output replacement 
     local bus auxiliary programs 
     1-8 local bus process augmentation program modules 
     miscellaneous auxiliary programs 
     1. initialization process augmentation 
     2. quarter hour check replacement 
     3. time trigger replacement 
     4. recalibration augmentation 
     5. external system interrupt augmentation 
     high speed bus auxiliary programs 
     1-4 high speed bus augmentation program modules 
     auxiliary subroutines 
     some number of subroutine program modules (number limited by sizes of system memory configured) 
     Advantages of the described architecture as compared to parking meters which simply employ a microprocessor with external program memory, the maximum size of which is dictated by the processor manufacturer, are: 
     The system is extensible essentially without bound both in available memory and functionality. 
     The core ROM based operating system support makes utilization of the disc memory for programming highly efficient. 
     Production costs are lower since no programming is required at production time. 
     Programming is a single step process performed at delivery time. Also, no sockets are required for external program memory. 
     Reliability is improved with no need for external memory sockets. 
     The core ROM based operating system support makes development of new applications easier since system programming for most meter functions is already in place and since the system is designed to allow auxiliary programs to be added employing the built-in communications package. 
     The use of the local bus interface as described in the aforementioned copending application is facilitated. Thus, the programs for operating a large number of peripheral devices which may have unique features for coin processing, LCD display, rate structure schedules and various events such as lighting, security and vehicle sensing are readily accessible with the system of the invention. 
     It will be understood that various changes and modifications may be made in the systems of this invention without departing from the spirit of the invention particularly as described in the following claims.