PRINTER, CONTROL METHOD THEREFOR AND RECORDING MEDIUM

Abstract: According to the present invention, a printer apparatus connected with a host computer, in such a manner that permits bidirectional communication, has a nonvolatile memory that allows its contents to be rewritten and read from the host computer. Allocated to the nonvolatile memory is an area for retaining a plurality of types of information for identifying the printer apparatus. Each piece of information comprises a key for identifying the type of the information and a terminator indicating the end of the information. Thus, efficiently disposing a plurality of pieces of information regarding the printer apparatus in the nonvolatile memory permits flexible change or addition of information.

Description: Technical Field The present invention relates to a printer apparatus connected to a host device in such a manner that bidirectional communication is possible, and more particularly, to a printer apparatus having a nonvolatile storage means such as a flash memory, and a control method and an information recording medium for the same. Background Art Hitherto, some electronic devices including printer apparatus have stored information specific to the electronic device in built-in nonvolatile memories. JP-A-7-64735 discloses a printing device which is connected to a network and which stores the printer-specific configuration information transmitted from a host in a nonvolatile memory and returns information regarding the printer configuration stored in the nonvolatile memory to the host in response to an inquiry command from the host. GB-A-2 176 637 discloses an electronic device having a nonvolatile memory built therein, and the nonvolatile memory has an apparatus information area for storing data specific to the apparatus, data being written to and read from the outside. However, in the printing device disclosed in JP-A-7-64735, the data of printer configuration information is stored in a predetermined block, i.e. data of a limited size from a predetermined address, allocated to the nonvolatile memory beforehand, and is read from the predetermined block, posing a problem in that it is impossible to rewrite or read a part of the information. For instance, in order to rewrite a part of the information, a host must read all the information stored in the predetermined block of the nonvolatile memory, edit the information, and write it back to the nonvolatile memory, thus making the processing complicated and taking a lot of time to complete the processing if the amount of information is large. In the electronic device disclosed in GB-A-2 176 637, apparatus-specific data is written to the area of a fixed capacity allocated to the nonvolatile memory in advance, presenting a problem in that a certain amount of memory is occupied regardless of the length of data to be actually stored, with consequent poor efficiency of utilization of the memory. For example, the information regarding the name of a manufacturer significantly varies in the length of data thereof, depending on each manufacturer, and it is necessary therefore to allocate a an area in the nonvolatile memory corresponding to the maximum length of data in advance, undesirably resulting in a large wasteful memory area. JP-A-7-334327 discloses a printer having a non-volatile memory for storing parameters. If a new parameter is to be stored, a previously stored parameter of low priority is erased and the new parameter stored instead. An object of the present invention is to solve the problems with the conventional arts set forth above and to efficiently store a plurality of pieces of printer apparatus information in a nonvolatile memory to permit flexible change, addition, and readout of the information. Disclosure of Invention This object is achieved by a method as claimed in claim 1 and a printer apparatus as claimed in claim 21. Preferred embodiments of the invention are subject-matter of the dependent claims. The method in accordance with the present invention can be supplied as a control program that can be implemented on a control unit, or can be provided through a recording medium in which the control program has been recorded. As the recording medium, a compact disc (CD-ROM), a floppy disk, a hard disk, a magneto-optical disk, a digital video disc (DVD-ROM), or a magnetic tape may be employed. By using these recording media, the programs can be introduced into an existing printer apparatus. Further, these programs can be registered in a WWW (World Wide Web) web site so that a user may download them to introduce the programs into an existing printer apparatus. The following will describe an embodiment of the present invention in conjunction with the accompanying drawings. Brief Description of Drawings Fig. 1 is a block diagram conceptually illustrating data exchange between a printer apparatus in accordance with the present invention and a host device. Fig. 2 is a diagram for explaining a first control command for writing various types of information in a printer information area. Fig. 3 is a diagram for explaining the first control command for reading various types of information from the printer information area. Fig. 4 is a diagram illustrating data formats and examples of printer specific information stored in the printer information area. Fig. 5 is a diagram showing an example of the name of a manufacturer, a model name, and a manufacturer's serial number stored in the printer information area. Fig. 6 is a diagram illustrating data formats and examples of printer setting information stored in the printer information area. Fig. 7 is a diagram conceptually illustrating the mapping of the printer specific information and setting information regarding the printer apparatus in the printer information area. Fig. 8 is a diagram for explaining a second control command for writing various types of information in a printer information area. Fig.9 is a diagram for explaining the second control command for reading various types of information from the printer information area. Fig. 10 is a flowchart illustrative of the processing for storing the printer specific information and the setting information regarding the printer apparatus. Fig. 11 is a flowchart illustrative of the processing for reading the printer specific information and the setting information regarding the printer apparatus. Fig. 12 is a flowchart illustrative of the processing for searching a key. Best Mode for Carrying Out the Invention Figure 1 is a block diagram conceptually showing the data exchange between a printer apparatus in accordance with the present invention and a host device. In the drawing, a host device 1 and a printer apparatus 2 are connected via an interface such as RS232, Centronics, etc. The host device 1 and the printer apparatus 2 mutually exchange data according to a preestablished protocol via the interface. The printer apparatus 2 comprises a CPU 3, which controls the entire system thereof, and a flash memory 4. The flash memory 4 is a nonvolatile memory that allows data to be electrically erased and rewritten on a block basis. Based on a control command from the host device 1, the CPU 3 reads data from and writes data into the flash memory 4 and sends the results back to the host device 1. In the present invention, the flash memory 4 has an area for retaining the printer specific information regarding the printer apparatus 2 (hereinafter referred to as "printer information area"). Examples of the printer specific information to be retained in the printer information area include the identification number, the model number, the firmware version, the manufacturer's name, the manufacturer's serial number, the manufacture date, the delivery date, maintenance information (the history of the product and the history of repair), the person in charge of management, etc. of the printer apparatus 2. It is also possible to store various types of setting information of the printer apparatus 2 (e.g. the setting of paper width, the setting of the number of columns that can be printed per line, the setting of communication speed, the setting of the presence of an optional function, etc.) in the printer information area. A user can obtain various types of information stored in the foregoing printer information area by sending out a predetermined read command from the host device 1. The user can also store various types of information in the foregoing printer information area by sending out a predetermined write command from the host device 1. If it is not desirable that the user rewrite various types of information regarding the printer apparatus 2, then the rewriting may be enabled only when the printer apparatus 2 is in a predetermined mode. It is also possible to manage the flash memory 4 by dividing it into an area wherein the user is allowed to rewrite and an area wherein no rewriting is enabled. An example of writing data to and reading data from the flash memory will be described with reference to the accompanying drawings. Figure 2 is a diagram showing a control command for writing various types of information to the printer information area. A write command 20 comprises a command code part 21 and a parameter part 22. The command code part 21 comprises an extension 23 and a function code 24, while the parameter part 22 comprises a functional extension parameter 25, a storage address 26, a stored data amount 27, and stored data 28. The extension 23 conforms to the ASCII notation character code <1CH>. The function code 24 is a code string for specifying a data storing function; in this example, two character codes are combined to specify the storing function. The functional extension parameter 25 specifies the code for storing data in the flash memory 4. The storage address 26 specifies an absolute address or an offset address of the flash memory 4 at which to start the storage processing. The stored data amount 27 specifies the data amount of the data 28 to be stored. The stored data 28 specifies the data string to be stored of the printer specific information or the setting information regarding the printer apparatus 2. The CPU 3 of the printer apparatus 2 performs the following operations in response to the write command 20: (1) The functional extension parameter 25 of the write command 20 is compared with a predetermined code, and if the functional extension parameter 25 does not agree with the code, then the storing of data is not performed. This makes it possible to disable destruction or change of data in the case of disagreement with the predetermined code. (2) The storage address 26 is compared with the area of the flash memory 4, and if the storage address 26 is out of the area of the flash memory 4, then the storing of data is not performed. Further, the stored data amount 27 is compared with the area of the flash memory 4, and if the stored data amount 27 specifies more than the area of the flash memory 4, then the storing of data is not performed. Furthermore, the storage address 26 plus the stored data amount 27 is compared with the area of the flash memory 4, and if the storage address 26 plus the stored data amount 27 exceeds the area of the flash memory 4, then the storing of data is not performed. These processings permit protection of the data in an area inappropriate for the data storage by the write command 20. (3) If a printing mode has been selected wherein print data sent from the host device 1 is expanded and stored in a line-by-line print buffer, then printing is executed in response to a printing command, and if unprinted data exists in the print buffer, then the storing of data is not performed. This makes it possible to prevent the elimination of unprinted data caused by interruption of the operation of the printer apparatus 2 due to the occurrence of a memory error while data is being stored, thus permitting the protection of print data, the printing of which has not yet been completed. (4) If a printing mode has been selected in which print data sent from the host device 1 is expanded and stored in a print buffer accommodating a plurality of lines, then printing is executed in response to a printing command, and if a printing area has been set, then the storing of data is not performed. This makes it possible to prevent the elimination of unprinted data caused by interruption of the operation of the printer apparatus 2 due to the occurrence of a memory error while data is being stored, thus permitting the protection of print data, the printing of which has not yet been completed. (5) If all of the functional extension parameter 25, the storage address 26, and the stored data amount 27 have appropriate values and if the state of the printer apparatus 2 is also appropriate (e.g. a case wherein neither (3) nor (4) applies), then the printer apparatus 2 begins the storing of data in the printer information area of the specified data amount from the specified address in the flash memory 4. This enables the storage of data sent from the host device 1 in the printer apparatus 2. (6) If the data to be stored 28 coincides with predetermined data, then the storing of data is aborted. This makes it possible to disable writing of the predetermined data to the flash memory 4. For instance, if the domain of data permitted as the data to be stored 28 includes only character codes, then writing of data other than character codes (out of the domain) is disabled. (7) If the data to be stored 28 is identical to the data stored in the flash memory 4, then the storing of the data is not performed. Thus, the frequency of writing to the flash memory 4 can be reduced. (8) Data is stored by executing "overwriting", so that previously stored data will be erased. This eliminates the need of a means for initializing the flash memory 4. (9) If a "write error" occurs during writing, the occurrence of the error will be indicated by an LED, a buzzer, etc., or notified to the host device 1 by sending an error status, a change in a signal line, or the like. This enables an operator or the host device 1 to ascertain that the storing has not been properly completed due to an error that has taken place in the printer apparatus 2. Figure 3 is a diagram showing a control command for reading data from the flash memory. The read command in this example specifies reading of data from the flash memory 4 and sending of data to the host device 1. A read command 30 comprises a command code part 31 and a parameter part 32. The command code part 31 comprises an extension 33 and a function code 34, while the parameter part 32 comprises a functional extension parameter 35, a read address 36, and a read data amount 37. The extension 33 conforms to the ASCII notation character code <1CH>. The function code 34 is a code string for specifying a data reading function; in this example, two character codes are combined to specify the reading function. The functional extension parameter 35 specifies the code for reading data from the flash memory 4. The read address 36 specifies an absolute address or an offset address of the flash memory 4 at which to start the reading. The read data amount 37 specifies the amount of data to be read. The CPU 3 of the printer apparatus 2 performs the following operations in response to the read command 30: (1) The functional extension parameter 35 of the read command 30 is compared with a predetermined code, and if the functional extension parameter 35 does not agree with the code, then the reading of data is not performed. This makes it possible to disable reading of data in the case of disagreement with the predetermined code. (2) The read address 36 is compared with the area of the flash memory 4, and if the read address 36 is out of the area of the flash memory 4, then the reading of data is not performed. Further, the read data amount 37 is compared with the area of the flash memory 4, and if the read data amount 37 specifies more than the area of the flash memory 4, then the reading of data is not performed. Furthermore, the read address 36 plus the read data amount 37 is compared with the area of the flash memory 4, and if the read address 36 plus the read data amount 37 exceeds the area of the flash memory 4, then the reading of data is not performed. These processings make it possible to disable reading of erroneous data that is not a target of the read command 30. (3) If all of the functional extension parameter 35, the read address 36, and the read data amount 37 have appropriate values, then the printer apparatus 2 reads data of the specified data amount stored in the printer information area from the specified address of the flash memory 4, and sends it to the host device 1. This enables the host device 1 to obtain the data stored in the printer apparatus 2. (4) If a "read error" has occurred during reading, then the occurrence of the error will be indicated by an LED, a buzzer, etc., or notified to the host device 1 by sending an error status, a change in a signal line, or the like. This enables an operator or the host device 1 to ascertain that the read data will not be sent due to an error that has taken place in the printer apparatus 2. (5) It is possible to add a "header code" or a "terminator code" to data to be sent. This allows the host device 1 to easily recognize the beginning and end of sent data. Thus, according to the present example, in writing and reading data, data of an arbitrary length can be written at an arbitrary address and data of an arbitrary length can be read from an arbitrary address by specifying an absolute address or an offset address of the flash memory and by further specifying a data length. Referring to the accompanying drawings, the following will describe writing and reading data to and from a flash memory according to an embodiment of the present invention. Figure 4 shows data formats of printer specific information stored in the foregoing printer information area. Each information stored in the printer information area comprises a key and a terminator as illustrated in (A) of the drawing. The key is a code added to the beginning of data to indicate the position of the beginning of the data; it is a 2-byte character formed of an ASCII character "K" and a consecutive number "n" (n is a natural number) that follows "K". The values of the consecutive number "n" of the key are predetermined according to the type of data to be stored. In one example, a manufacturer's name is assigned to "K1", a model name is assigned to "K2", and a manufacturer's serial number is assigned to "K3". The terminator indicates the end of data; it is a 1-byte NULL character string. The length of each piece of data to be stored is different, and the end of data is determined by the position of the terminator. In the drawing. (B) illustrates an example wherein EPSON" is stored as a manufacturer's name in accordance with the foregoing format. The key "K1" corresponding to the manufacturer's name is given at the key position of the data, and the NULL character is given at the end position of the data. The amount of memory occupied in this case is two bytes of the key plus five bytes of data plus one byte of the terminator, totaling to eight bytes. In the drawing, (C) represents the foregoing data by hexadecimal ASCII code. "H" is a notation mark indicating that the numeral is hexadecimal. When a user needs to acquire the name of the manufacturer of the printer apparatus 2, the user sends out from the host device 1 a predetermined read command accompanied by the foregoing "K1" ("4BH31H" according to the ASCII code) as a parameter. Upon receipt of the read command, the CPU 3 of the printer apparatus 2 searches for "K1" in the printer information area and retrieves data therefrom until a terminator appears, and sends it back to the host device 1. Figure 5 shows an example of a manufacturer's name, a model name, and a manufacturer's serial number stored in the printer information area in accordance with the foregoing data format. The example shows, for instance, a case wherein "EPSON" is stored as the manufacturer's name, "SE-C1988ll" is stored as the model name, and "3B20022933" is stored as the manufacturers serial number. "K1" is added at the beginning of the manufacturer's name, "K2" is added at the beginning of the model name, and "K3" is added at the beginning of the manufacturer's serial number, respectively, the NULL character string being added at the end of each piece of data. In this case, as shown in the drawing, the respective pieces of actual data to be stored have different data lengths. However, data is read from the position of a corresponding key to the position of the following terminator; hence, desired data can be read regardless of the actual data length. The printer information area is capable of further including the setting information of the printer apparatus 2. By writing various types of information set by conventional hardware DIP switches to the printer information area, the information can be set or changed more easily. Figure 6 (A) illustrates the data format of the setting information of the printer to be stored in the printer information area. Basically, as in the case of the foregoing printer specific information, the setting information is formed by adding a key denoted by "Kn" and a terminator denoted by a NULL character before and after the setting information. In this case, the key for the setting information is represented by "K4". The setting information may include one or a plurality of setting switches (SW1 through SWn) corresponding to one DIP switch. In the drawing, (B) shows the information recorded to each setting switch, the information being binary. Each setting switch is composed of 8 bits (1 byte), two higher-order bits being fixed at 01, while six lower-order bits providing a set value. Fixing the two higher-order bits at 01 (or 10) allows a terminator to be distinguished from setting switch information. Therefore, six different pieces of ON/OFF information can be stored by using a single setting switch. In the drawing, (C) and (D) illustrate data serving as the setting information wherein three setting switches (SW1 through SW3) are provided and the setting of all the switches is OFF, i.e., "0", is expressed by ASCII codes and ASCII characters based on the hexadecimal notation. When the setting of all the switches is OFF, each switch is represented by "01000000" including the beginning two fixed bits. This is indicated by "40H" of (C) in the drawing and "@" of (D) in the drawing. When a user needs to acquire the setting information of the printer apparatus 2, the user sends out from the host device 1 a predetermined read command accompanied by the foregoing "K4" ("4BH34H" according to the ASCII code) as a parameter. Upon receipt of the read command, the CPU 3 of the printer apparatus 2 searches for "K4" in the printer information area and retrieves data therefrom until a terminator appears, and sends it back to the host device 1. At the host device 1, the first two bits among eight bits corresponding to each setting switch are ignored, and the remaining six bits are retrieved thereby to obtain the information regarding each setting switch. Figure 7 conceptually illustrates the mapping of the printer specific information (a manufacturer's name, a model name, and a manufacturer's serial number) and the setting information regarding the aforesaid printer apparatus 2 in the printer information area. The foregoing information in the printer information area A is mapped with no spaces in sequence from the beginning of the area according to the consecutive numbers of the keys. One block in the drawing is equal to one byte. If a request for reading data is received from the host device 1, the CPU 3 of the printer apparatus 2 searches for an appropriate key from the start of the memory area. When the appropriate key has been found, the CPU 3 reads the data from that position to the next NULL character as the requested data and sends it back to the host device. In the above description, the key has been denoted by a mark "Kn" and the terminator has been denoted by the NULL character; however, other marks that permit data to be identified may be employed. A plurality of keys may be set; "E1, E2, ..., En" or "Y1, Y2, ..., Yn" or the like may be set in addition to the "K1, K2, ..., Kn". This permits an application wherein information management is performed by, for example, providing different operators with different keys. Figure 8 shows an embodiment of the control command for writing various types of information in the printer information area. This embodiment differs from the corresponding command in the example described above in that it has a key 48 in place of the storage address 26 and the data to be stored amount 27. A write command 40 comprises a command code part 41 and a parameter part 42. The command code part 41 comprises an extension 43 and a function code 44, while the parameter part 42 comprises a parameter amount 45, a functional extension parameter 46, a function detail code 47, a key 48, and stored data 49. The extension 43 conforms to the ASCII notation character code <1DH>. The function code 44 is a code string for specifying the function for editing a printer information area. The parameter amount 45 specifies the amount of the parameter of the parameter part. The functional extension parameter 46 specifies the code for storing data in the flash memory 4. The function detail code 47 specifies the data storing function. The key 48 is a code string for identifying data; it is added at the beginning of data to be stored. The data to be stored 49 specifies a data string of printer specific information or the setting information regarding the printer apparatus 2. In this example, the functional extension parameter 46 is specified by a 1-byte character code, and the function detail code 47 and the key 48 are specified by 2-byte character codes; hence, the parameter amount 45 will be (5 + the data to be stored amount) bytes. The CPU 3 of the printer apparatus 2 performs the following operations in response to the write command 40: (1) The functional extension parameter 46 of the write command 40 is compared with a predetermined code, and if the functional extension parameter 46 does not agree with the code, then the storing of data is not performed. This makes it possible to disable destruction or change of data in the case of disagreement with the predetermined code. (2) The (stored data 49 + 3) bytes is compared with the remaining capacity of the printer information area, and if the (the stored data 49 + 3) bytes is greater than the remaining capacity of the printer information area, then the storing of data is not performed. Here, the data to be stored amount is given by (the parameter amount 45 - 5) bytes. Three bytes are added to the data to be stored amount because the data stored in the printer information area includes a two byte key and a one byte terminator. This permits protection of the data in the area inappropriate for the data storage of the write command 40. (3) If a printing mode has been selected wherein print data sent from the host device 1 is expanded and stored in a line-by-line print buffer, then printing is executed in response to a printing command, and if unprinted data exists in the print buffer, then the storing of data is not performed. This makes it possible to prevent the elimination of unprinted data caused by interruption of the operation of the printer apparatus 2 due to the occurrence of a memory error while data is being stored, thus permitting the protection of print data, the printing of which has not yet been completed. (4) If a printing mode has been selected in which print data sent from the host device 1 is expanded and stored in a print buffer accommodating a plurality of lines, then printing is executed in response to a printing command, and if a printing area has been set, then the storing of data is not performed. This makes it possible to prevent the elimination of unprinted data caused by interruption of the operation of the printer apparatus 2 due to the occurrence of a memory error while data is being stored, thus permitting the protection of print data, the printing of which has not yet been completed. (5) If the functional extension parameter 46 and the key 47 have appropriate values and if the state of the printer apparatus 2 is also appropriate (e.g. a case wherein neither (3) nor (4) applies), then the CPU 3 begins the storing of data in the printer information area. This enables the storage of data sent from the host device 1 in the printer apparatus 2. (6) If the data to be stored 49 coincides with predetermined data, then the storing of data is aborted. This makes it possible to disable writing of the predetermined data to the flash memory 4. For instance, if the domain of data permitted as the data to be stored 49 includes only character codes, then writing of data other than character codes (out of the domain) is disabled. (7) If the data to be stored 49 and the data stored in the flash memory 4 are the same, then the storing of the data is not performed. Thus, the frequency of writing to the flash memory 4 can be reduced. (8) Data is stored by executing "overwriting", so that previously stored data will be erased. This eliminates the need of a means for initializing the flash memory 4. (9) If a "write error" occurs during writing, the occurrence of the error will be indicated by an LED, a buzzer, etc., or notified to the host device 1 by sending an error status, a change in a signal line, or the like. This enables an operator or the host device 1 to ascertain that the storing has not been properly completed due to an error that has taken place in the printer apparatus 2. (10) The key 48 is searched for in sequence from the beginning of the printer information area, all data from the first matching key to a terminator is deleted, and newly specified data 49 to be stored is stored. This makes it possible to prevent the presence of a plurality of the same keys. (11) A terminator is automatically added in storing the data 49 to be stored in the printer information area. This permits reliable storing in accordance with the data format of (key + stored data + terminator). Figure 9 shows an embodiment of the control command for reading various types of information from the printer information area. This embodiment differs from the corresponding command in the example described above in that it has a key 58 in place of the storage address 36 and the stored data amount 37. A read command 50 comprises a command code part 51 and a parameter part 52. The command code part 51 comprises an extension 53 and a function code 54, while the parameter part 52 comprises a parameter amount 55, a functional extension parameter 56, a function detail code 57, and a key 58. The extension 53 conforms to the ASCII notation character code <1DH>. The function code 54 is a code string for specifying a function for editing the printer information area. The parameter amount 55 specifies the parameter amount of the parameter part. The functional extension parameter 56 specifies the code for reading data to the flash memory 4. The function detail code 57 specifies the function for reading data. The key 58 is a code string for identifying data, and it specifies data to be read. In this example, the functional extension parameter 56 is specified by a 1-byte character code, and the function detail code 57 and the key 58 are specified by 2-byte character codes; hence, the parameter amount 55 will be five bytes. The CPU 3 of the printer apparatus 2 performs the following operations in response to the read command 50: (1) The functional extension parameter 56 of the read command 50 is compared with a predetermined code, and if the functional extension parameter 56 does not agree with the code, then the reading of data is not performed. This makes it possible to disable reading of data in the case of disagreement with the predetermined code. (2) If the functional extension parameter 56 and the key 58 have valid values, then the CPU 3 searches for the key from the beginning of the printer information area, reads data between the first matching key and a terminator, and sends it to the host device 1. This enables the host device 1 to obtain the data stored in the printer apparatus 2. (4) If a "read error" has occurred during reading, then the occurrence of the error will be indicated by an LED, a buzzer, etc., or notified to the host device 1 by sending an error status, a change in a signal line, or the like. This enables an operator or the host device 1 to ascertain that the read data will not be sent due to the error that has taken place in the printer apparatus 2. (5) It is possible to add a "header code" or a "terminator code" to data to be sent. This allows the host device 1 to easily recognize the beginning and end of sent data. (6) If no data exists between a key and a terminator, then the CPU 2 sends a message to that effect to the host device 1. This allows the host device 1 to distinguish a case wherein no key exists from a case wherein no data exists although a key exists. (7) If a specified key cannot be detected, no terminator can be detected, or data out of a domain is detected in the data between a key code and a terminator, then a message indicating that there is something wrong with the data is sent to the host device 1. Referring now to an accompanying flowchart, the processing for writing and reading data to and from the flash memory 4 from the host device 1 will be described. Figure 10 shows a flowchart of the processing for storing data in the printer information area of the flash memory 4. When the data write command 40 is received from the host device 1, the CPU 3 of the printer apparatus 2 searches for the key specified by the write command 40 in the printer information area (S101). If a matching key is found (Yes in S102), then the CPU 3 deletes the data from the key to the first terminator (S103), and re-stores the data that has been stored following the deleted data by moving it forward (S104). Next, the CPU 3 stores the data specified by the write command 40 at the tail of the data already stored in the printer information area. On the other hand, if no key matching the key specified by the write command 40 exists in the printer information area (No in S102), then the CPU 3 moves to step S105 wherein it stores the data specified by the write command 40 at the tail of the data already stored in the printer information area. Thus, the data is relocated according to the size of data at the time of storing the data; hence, data can always be arranged with no space, permitting effective use of the printer information area. Furthermore, as long as the capacity of the printer information area permits, a user may assign predetermined keys to, for example, maintenance information, firmware version information, etc. and store them. Figure 11 shows a flowchart of the processing for reading data from the printer information area of the flash memory 4. Upon receipt of the data read command 50 from the host device 1, the printer apparatus 2 searches for the key specified by the read command 50 in the printer information area (S201). If a matching key is found (Yes in S202), then the printer apparatus 2 reads the data from the key to the first terminator (S203), and sends the read data to the host device 1 (S204). On the other hand, if no key matching the key specified by the read command 50 is found in the printer information area (No in S202), the printer apparatus 2 outputs an error and terminates the processing (S205). Thus, the user can easily obtain desired data simply by specifying a key attached to data. The processing for finding a key (S102 and S202) in storing data and reading data set forth above will now be described. Figure 12 shows the flowchart of the processing for finding a key. Upon receipt of the write command 40 or the read command 50 from the host device 1, the printer apparatus 2 sets the address at which the search in the flash memory 4 is begun to a variable Pt. In this example, Pt is used to set the leading address in the printer information area (S301). Further, a flag indicating a valid/invalid key search is set to valid (S302). In this example, Flag=0 indicates valid, whereas Flag=1 indicates invalid. Subsequently, 1-byte data stored at the address Pt is read (S303), and if the key search is valid (Yes in S304), then it is determined whether the read data is included in a predetermined key domain (S305). In this example, the range from 20h to 7Eh in the character code table is defined as the key domain. If the read data is found to be within the domain in step S305, then it is determined whether the search key specified by the command agrees with the read data (S306), and if they agree with each other (Yes in S306), then it is decided that the key has been found and the searching is terminated. In the case of disagreement (No in S306), then it can be determined that the read data is different from the key specified by the command; therefore, the key search flag is set to invalid (Flag=1) (S307). On the other hand, if the key search is invalid in step S304 (No in S304), then it is determined whether the data read in step S303 is a terminator (S310). If the data is a terminator, then the key search flag is set to "0" to validate the key search (S311). If the data is not a terminator, then the program proceeds to step S308 with the key search set to invalid. This makes it possible to handle only the data stored at the leading address in the printer information area and the data immediately following the terminator for the key search. Then, in step S308, it is determined whether the address Pt is the last address in the printer information area, and if it is the last address (No in S308), then an error code indicating that the key specified by the command has not been found is output, and the key searching is terminated (S312). If the address Pt is not the last address (Yes in S308), then the program increments the address (S309) and goes back to step S303 to repeat the above processing. Thus, by taking advantage of keys that are stored at the heads of the printer information area or immediately after terminators, the key search flag is rendered valid when a terminator is found so as to find a key. This makes it possible to prevent an error in which even if data identical to a key exists in data, the data is erroneously detected as the key. When a key has been found, the data up to where the next terminator is found can be assumed to be the requested data. This allows a host device to easily write and read data without performing address management in the nonvolatile memory. In the present embodiment, it is also possible to implement a function for deleting data associated with a specified key or a function for sending the occupied capacity or remaining capacity of a printer information area by expanding the function detail code. For instance, data can be deleted by setting the function detail code to 0, the occupied capacity can be sent by setting it to 3, and the remaining capacity can be sent by setting it to 4. The capacity of the printer information area can be known from the occupied capacity and the remaining capacity. Alternatively, the function for sending the capacity of the printer information area may be added to the function detail code. An embodiment wherein the present invention is used as a system will now be described. First, the printer specific information regarding a printer apparatus is stored in the printer information area of the flash memory 4 included in the printer apparatus 2 by specifying a key using the write command 40. The basic information in this embodiment is as shown below: Information K3: Manufacturer's serial No. of printer apparatus Information K5: Purchase date of the printer apparatus Information K6: Telephone number for inquiry Information K7: Name of person to contact for inquiry Information K8: Name of person in charge of management of printer apparatus Information K9: Place where document of printer apparatus is retained If paper runs out while the printer apparatus 2 is in operation and if an operator does not know how to add paper, the operator can obtain "Information K9: Place where document of printer apparatus is retained" from the printer information area by specifying a key by the read command 50. Thus, even an operator who does not know the place where the document is kept can check the method for adding paper described in the document. At this time, if the operator is still not sure about how to add paper after reading the document, then the operator can obtain instructions from a person versed in the handling of the product by acquiring "Information K8: Name of person in charge of management of printer apparatus" from the printer information area by using the read command 30 or 50. Next, if any problem that requires an inquiry to the manufacturer occurs during the operation of the printer apparatus 2, then the operator can receive appropriate advice over a telephone by acquiring "Information K6: Telephone number for inquiry" and "Information K7: Name of person to contact for inquiry" from the printer information area by using the read command 30 or 50. If it is necessary to tell "Information K3: Manufacturer's serial No. of printer apparatus" and "Information K5: Purchase date of the printer apparatus" of the printer apparatus 2 at the time of an inquiry, such information can be obtained and prepared from the printer information area by using the read command 30 or 50. Further, if the person to contact for inquiry has been changed, then only "Information K7: Name of person to contact for inquiry on printer apparatus" is re-stored in the printer information area by using the write command 20 or 40 thereby permitting the information to be updated without affecting other data. Thus, it becomes possible to easily and positively address a problem with a printer apparatus by storing the printer specific information for managing the printer apparatus in the flash memory of the printer apparatus by using the write command and by preparing a system for acquiring required information by the read command when the host device needs it. In the foregoing embodiment, a flash memory has been used as the nonvolatile memory; however, other memories such as EEPROMs or RAMs with backup features may be used as long as stored contents can be retained in a state wherein no power is supplied. The data stored in the nonvolatile memory is not limited to that shown in the above embodiments; it may alternatively be data regarding various types of printer apparatuses or a part of the data shown in the embodiments. In the nonvolatile memories, font data or programs, etc. may be also stored. Thus, according to the present invention, an arbitrary block in a nonvolatile memory can be specified by a key to write or read data of an arbitrary data length. Moreover, a plurality of pieces of information concerning a printer apparatus can be efficiently stored in a nonvolatile memory, thus permitting flexible change or addition of data.

Claims: A method of controlling a printer apparatus adapted to receive commands and data from a host device (1) and to perform printing based on a command and data from said host device (1) and comprising nonvolatile storing means (4) capable of retaining stored contents in a state when no power is supplied to said printer apparatus, said control method comprising: a data storing step for storing in a certain area of said nonvolative storing means (4), in response to a first command (41) from said host device (1), data (49) representing information specific to said printer apparatus received following the first command (41); and a data reading step for reading, in response to a second command (51) from said host device (1), data stored in said nonvolatile storing means (4) and for sending the read data to said host device (1); characterized in that said data storing step stores a key (48), which is specified by said first command (41) and which identifies the type of said data (49), said data (49) itself of an amount (45) specified by said first command (41), and a terminator indicating the end of said data (49), in said nonvolatile storing means (4). The method according to Claim 1, further comprising: a first key-searching step for searching said key (48) specified by said first command (41) in said area of said nonvolatile storing means (4); wherein, when said first key-searching step finds said key (48), said data storing step deletes the data stored in the nonvolatile storing means (4) from said key (48) to said terminator, and said data storing step stores said key (48) and data (49) specified by said first command (41) and said terminator according to a result of said first key-searching step. The method according to Claim 2, further comprising: an information rearranging step for rearranging the placement of information stored in said area of said nonvolatile storing means (4); wherein if said stored data has been deleted by said data storing step, then the data stored behind said deleted data is moved ahead by the amount of deleted data. The method according to any one of Claims 1 to 3, wherein said data storing step stories said key (48), said data (49), and said terminator immediately after the last terminator among said terminators stored in said area of said nonvolatile storing means (4). The method according to any one of Claims 1 to 4, further comprising: a detection step for detecting whether predetermined data exists in said data; wherein, if predetermined data is found among the data (49) to be stored, then said data storing step aborts storing subsequent data. The method according to any one of Claims 1 to 5, further comprising: a first printing control step for expanding a predetermined amount of print data received from said host device (1) into a print buffer accommodating a plurality of lines, then printing the contents of said print buffer; a second printing control step for sequentially printing print data received from said host device (1); and a printing-mode selecting step for selecting one of said first and second printing control steps in response to a command from said host device (1); wherein said data storing step does not carry out the storing of said data if said first printing control step has been selected according to a result of said printing-mode selecting step. The method according to any one of Claims 1 to 6, further comprising: a first data-amount verifying step for determining whether the amount (45) of data specified by said first command (41 is valid; wherein said data storing step does not carry out the storing of said data (49) if said data amount is not valid according to a result of said first data-amount verifying step. The method according to any one of the preceding Claims, further comprising: a second key-searching step for searching the key (58) specified by said second command (51) in said area of said non volatile storing means (4); wherein said data reading step reads and sends the data from the position of said key found by the second key-searching step to said terminator. The method according to Claim 8, wherein, if no data exists between said key (58) and said terminator, then said data reading step sends a message to that effect. The method according to Claim 8, wherein, if said key (58) specified by said second command (51) does not exist, then said data reading step sends a message to that effect. The method according to Claim 8, wherein, if said terminator does not exist, then said data reading step sends a message to that effect. The method according to Claim 8, wherein, if predetermined data is found among read data, then said data reading step sends a message to that effect. The method according to any one of the preceding Claims, further comprising: a data deleting step for deleting data stored in said non volatile storing means (4) in response to a third command from said host device (1); and a third key-searching step for searching a key, which has been specified by said third command, in said area of said non volatile storing means (4); wherein, when the third key-searching step finds said key, said data deleting step deletes the data from the position of said key to said terminator. The method according to Claim 13, further comprising: an information rearranging step for rearranging the placement of information stored in said area of said non volatile storing means (4); wherein if said data has been deleted by said data deleting step, then the data stored behind said deleted data is moved ahead by the amount of said deleted data. The method according to Claim 13 or 14, further comprising: a first printing control step for expanding a predetermined amount of print data received from said host device (1) into a print buffer accommodating a plurality of lines, then printing the contents of said print buffer; a second printing control step for sequentially printing print data received from said host device (1); and a printing-mode selecting step for selecting one of said first and second printing control steps in response to a command from said host device (1); wherein said data storing step does not delete said data if said first printing control step has been selected according to a result of said printing-mode selecting step. The method according to any one of the preceding Claims, further comprising: an occupied-capacity detecting step for detecting and sending an occupied capacity in said area of said storing means (4) in response to a fourth command from said host device (1). The method according to any one of Claims 1 to 15, further comprisinga remaining-capacity detection step for detecting and sending a remaining capacity of said area of said non volatile storing means (4) in response to a fourth command from said host device (1). The method according to claim 1, further comprising: an area-capacity sending step for sending the capacity of said area of said non volatile storing means (4) in response to a fifth command from said host device (1). The method according to any one of Claims 1 to 18, further comprising: a step for setting a code for authorizing the reading of said data in accordance with said first command (41); and a step for comparing a code for reading said data specified by said second command (51) with said code set by said first command (41); wherein said data reading step performs the reading and sending of said stored data only if said codes agree with each other according to a result of said code-comparison step. The method according to any one of Claims 1 to 19, wherein: said non volatile storing means (4) has a plurality of areas; and said control method comprises a step for disabling the storing of data in at least one area of said plurality of areas of said non volatile storing means (4) and/or the reading of data from at least one area of said plurality of areas of said non volatile storing means (4). A printer apparatus adapted to receive commands and data from to a host device (1) and to perform printing based on a command and data from said host device (1), comprising: nonvolatile storing means (4) capable of retaining stored contents in a state when no power is supplied to said printer apparatus, wherein said storing means (4) has an area for storing a plurality of types of information for identifying said printer apparatus, characterized in that said information comprises a key that identifies the type of said information representing information specific to said printer apparatus and a terminator that indicates the end of said information. The apparatus according to Claim 21, wherein said key is positioned at a leading address of said area of said storing means (4) or immediately following said terminator. The apparatus according to Claim 21 or 22 further comprising means for carrying out the steps of the method according to any one of Claims 1 to 20. A computer readable storage medium storing program means which when loaded into and executed by a printer apparatus according to any one of Claims 21 to 23 cause the printer apparatus to execute the steps of the method according to any one of claims 1 to 20.

Inventors: FUKANO KAZUKO, KOAKUTSU NAOHIKO, MOCHIZUKI HIDETAKE, FUKANO, KAZUKO, KOAKUTSU, NAOHIKO, MOCHIZUKI, HIDETAKE
Applicants: SEIKO EPSON CORP, SEIKO EPSON CORPORATION
Application year: 1998
Main classification: G06F3
IPC codes: G06F3