JPH04313117A - Printer - Google Patents

Abstract

PURPOSE:To simply change a control program according to the change of a control code system for a printer. CONSTITUTION:A printer is provided to control a printer mechanism 9 in accordance with the control code give from the outside when a CPU 23 carries out a control program stored previously. Then the printer is provided with a 1st nonvolatile program memory 33 which stores a 1st part where the program that is forcibly changed with the change of a control code system is included and the program used for control of a printer mechanism is not included and 2nd nonvolatile program memory 31 which stores a 2nd part where excluding the 1st part. The memory 33 can be electrically rewritten.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer used in combination with an information processing device such as a computer, and particularly to storage and rewriting of a control program therefor.

0002

[Prior Art] Printer control programs are stored in EPROM.
Or stored in mask ROM or program ROM
is stored in a single-chip CPU that can be built in, and mounted on a circuit board. In principle, it is impossible to change the control program after the product is completed, so all possible specifications that may be necessary are included in the contents of the control program to avoid the need for changes.

By the way, printers that can be connected to a plurality of types of host computers from different manufacturers are known. Typically, different manufacturers use different control code systems, so these types of printers are required to operate with any of a plurality of control code systems. Therefore, in a control program for such a printer, the control code analysis portion thereof requires a program capacity equivalent to that of a plurality of normal printers in order to support all of the plurality of control code systems. However, such a large-capacity program requires a great deal of effort and time to develop because of its large capacity and complexity. Furthermore, the complexity of control code analysis leads to a decrease in printer throughput.

Alternatively, a plurality of derivative devices each corresponding to different control code systems may be manufactured by installing different control programs on common hardware. In such a case, if there are many different models and the number of each model is small, there will be waste in manufacturing and management.

Furthermore, it is also conceivable to install hardware to which additional programs can be connected, and to support control programs with different control code systems as an optional cartridge or card. However, in this case, such additional functions increase costs.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to enable a printer to easily change a control program to accommodate different control code systems.

[0007]

[Means for Solving the Problems] The present invention is a printer that controls a printer mechanism by having a CPU execute a control program stored in advance in response to a control code given from the outside. ,
a nonvolatile first program memory that stores a first portion that includes a program that is forced to change due to a change in the control code system and does not include a program for controlling the printer mechanism; and a portion that excludes the first portion. and a non-volatile second program memory storing a second portion, the first program memory being electrically rewritable.

[0008]

[Effect] If the control code system used is changed,
This can be easily handled by rewriting only the program portion in the first program memory. Moreover, since the program for controlling the prompter mechanism is not changed, safety is guaranteed even if there is an error in the above rewriting.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall hardware configuration of an embodiment of a printer according to the present invention.

In FIG. 1, a printer mechanism 9 includes a carriage motor 1, a paper feed motor 3, a print head 5, and a group of sensors 7 such as a paper sensor and a temperature sensor;
An operation panel 11 including operation switches and an LED display is connected to a CPU 23 that controls the entire printer via drivers 13, 15, 17 and interface circuits 19, 21, respectively. Also,
This CPU 23 has an interface circuit 29 for communicating with a host computer 27 via a CPU bus 25.
, PROM31 and EEPRO that store the control program
M33, a work RAM 35, and a character generator ROM 37 that stores character patterns.

A control program for operating the CPU 23 is stored separately in a PROM 31 and an EEPROM 33.

The control program portion stored in the PROM 31 includes: ■ Control of the mechanism 9 ■ Control of the operation panel 11 ■ Initialization operation at reset ■ Interface with the sensor group 5 ■ Data reception from the host computer 27 (Centronics interface, RS-232C interface, etc.), hardware control such as data buffering control, basic operations of the printer, and rewriting of the EEPROM 33.

On the other hand, the control program portion stored in the EEOROM 33 includes portions related to (1) analysis and execution of different control codes by the host computer 27, and (2) functions of the operation switches of the operation panel 11 and the display device.

In short, the portion of the control program that depends on the printer hardware is stored in the PROM 31, and the portion that depends on the host computer, particularly the portion related to control code analysis, is stored in the EEPROM 33. When the type of host computer 27 is changed and the control code system is changed, this can be handled by rewriting the program portion stored in the EEPROM 33. In that case, even if a mistake occurs in the rewriting, the program part related to the control of the mechanism remains unchanged, so there is no risk of situations such as large current flowing to the motor or head, and safe operation is possible. Guaranteed.

FIG. 2 shows an example of memory mapping in this embodiment.

As shown in the figure, the address space for program storage in the address space of the CPU 23 is divided into two parts, one for the PROM 31 and the other for the EEPOM 33.
assigned to. The start address of the program is placed in the PROM 31. That is, when the control program starts, it always starts from the program in PROM 31.

FIG. 3 shows the details of the functions realized by the CPU 23 executing the control program in the embodiment shown in FIG. 1, together with the relationship with other hardware within the printer.

Referring to FIG. 3, the hardware configuration will first be explained. As already explained, the printer mechanism 9 includes the print head 5, the carriage motor 1,
There is a paper feed motor 3 and a sensor group 7 such as a head temperature sensor and a paper sensor. These are connected to a head driver 17, a carriage motor driver 13, a paper feed motor driver 15, and a sensor interface circuit 19, respectively. In addition, the operation panel 11
includes a group of various operation switches 39 and an LED display 41, which are connected to a switch interface circuit 43 and a display driver 45, respectively. moreover,
The interface circuit 29 and character generator ROM 37 for the host computer 27 that have already been explained
In addition, there is a power supply circuit 47 for power supply, a reset circuit 49 for performing a reset operation when the power is turned on or when a reset request occurs, and a voltage monitor for detecting a drop in the voltage supplied to the mechanism 9 (mainly the head 5). A circuit 51 and the like exist as hardware.

As described above, the control program is divided into two parts: a part that depends on the printer hardware 50 and a part that depends on the host computer 27 (control code), the former being stored in the PROM 31 and the latter being written. It is stored in the EEPROM 33 so that it can be changed. In FIG. 3, the functions realized by executing the former program are shown in block 52, and the functions realized by executing the latter program are shown in block 54.

The functional blocks 52 implemented by programs that depend on the hardware 50 include, for example, the following. Interface protocol control unit 53
The host computer 27 controls the interface circuit 29 by sending status information such as errors and busy to the interface circuit 29 according to the buffer status and device status.
The input data from the interface circuit 29 is taken in from the interface circuit 29. The data input buffer control unit 55
It functions as a buffer for input data taken in by the interface protocol control unit 53, and the buffer status is notified to the interface protocol control unit 53. The decompression processing unit 57 is a character generator RAM.
The compressed pattern data of the designated character code is read out from 37 and subjected to decompression processing. The panel control unit 59 communicates switch status and display control information with the panel interface circuit 21. The sensor control unit 61 receives detection information from the sensor interface circuit 19 and the voltage monitoring circuit 51, and determines whether the device status is normal or not.
This is used to determine abnormalities. Further, the paper feed control section 63 sends a motor control signal for paper feeding to the paper feed motor driver 15. The carriage speed control section 65 is
It sends a motor control signal for carriage movement to the carriage motor driver 13. Furthermore, the print position control section 67 determines the print start timing based on information defining the print start position, such as the left margin. The print control unit 69 starts printing control according to the print start timing determined by the print position control unit 67, and controls the head driver 17 by giving the print timing and print data determined based on the print density to the head driver 17. It is.

On the other hand, the functional block 54 implemented by a program depending on the control code includes, for example, the following. The command analysis section 71 receives input data from the data input buffer control section 55, decodes it, and distinguishes it into image data, commands, and character codes. The image data processing section 73 receives image data from the command analysis section 71 and writes it into the image data buffer 75. The command execution unit 77 receives a command from the command analysis unit 71 and parameters from the data input buffer control unit 55, and generates control information for executing the command. This control information includes, for example, print position control information for defining the relationship between each bit in the image data buffer 75 and the print position, such as when executing a tab, and print start position such as the left margin. Print start position information for specifying, print mode information for specifying print density and print speed, and vertical tabs and line spacing, etc.
There is line position control information for controlling line position by controlling paper feed, etc. The character code processing unit 79 receives the character code from the command analysis unit 71, gives address designation to the character generator ROM 37 based on the character code, receives the read character pattern data from the expansion/compression processing unit 57, and stores it in the image data buffer. 75. The image data buffer 75 receives print position control information from the command execution section 77, reads out the image data and character patterns written therein, and supplies them as print data to the print control section 69. The print mode control unit 81 receives print mode information from the command execution unit 71, and specifies the print density to the print control unit 69, and controls the traveling speed of the carriage to the carriage speed control unit 65.
It is something that can be specified. Further, the switch function determining unit 83 receives the state information of the operation switch from the panel control unit 59, and issues a line feed or form feed request to the paper feed control unit 63, a stop request to the state control unit 85, etc. It is something to do. The state control unit 85 receives the output information from the sensor control unit 61 and the switch function determination unit 83, and notifies the interface protocol analysis unit 53 of the device status such as error or busy, and the command analysis unit 7.
1 to stop execution, a display request to the panel control unit 59,
etc.

Next, the operation of the embodiment configured as described above will be explained, taking as examples the setting of the left margin (printing start position) and the printing of image data.

The control code for setting the left margin can be expressed as follows, for example, according to two different control code systems currently in use. ■ First control code system ESC "l" n This means that n x current character size becomes the left margin. ■ Second control code system ESC “L” n1 n2 n3 This is {(n1 −30H )×100+(n2 −30
H)×10+(n3−30H)}×current character size is the left margin.

Referring to FIG. 3, this control code is input from the host computer 27 to the interface circuit 29, and is passed through the interface protocol control section 53 and data input buffer control section 55 to the command portion ("ESC "l""). or “ESC “L””)
The command analysis unit 71 inputs its parameter part (“n”
or “n1 n2 n3”) is given to the command execution unit 77.

The operations of the command analysis section 71 and command execution section 77 in this case are shown in the flowcharts of FIGS. 4 and 5. Here, the flow in FIG. 4 corresponds to the case where the control program in the EEPROM 33 corresponds to the first control code system, and the flow in FIG. 5 corresponds to the case to the second control code system.

As shown in FIGS. 4 and 5, the command analysis section 7
1 recognizes that a left margin setting is requested from the command part of the control code, and then the command execution unit 77 calculates the print start position N from the parameters.

Referring to FIG. 3, the calculated print start position N is given to the print position control section 67, and
The signal is transmitted to the head driver 17 through the signal.

Next, an example of a control code for printing image data is shown below. ■ First control code system ESC * 27H n1 n2 data This follows n2 (n2 × 256 + n1
) x 3 bytes of data is printed as an image with the MSB at the top. ■ Second control code system ESC J n1 n2 n3 n4
Data This is n4 followed by {(n1 −3
0H )×1000+(n2 −30H)×100+
(n3 - 30H) x 10 + (n4 - 30H)}
This means that x3 byte data is printed as an image with the MSB at the bottom.

Similar to the above example, this control code also includes the command part (“ESC *27H” or “ESC
J") is sent to the command analysis section 71, and the parameter part ("
n1 n2” or “n1 n2 n3
n4'') is given to the command execution unit 77. The image data is then written into the image data buffer 75 through the image data processing section 75 under the control of the command processing section 77, and then transmitted to the head driver 17 through the print control section 69. This operation is shown in the flowcharts of FIGS. 6 and 7, in which FIG. 6 corresponds to the first control code system and FIG. 7 corresponds to the second control code system.

As described above, the processing content for the control code differs depending on the control code system, but since the control program portion that controls the different processing is stored in the EEPROM 33 and can be rewritten, it is easy to deal with different control code systems. It is.

Next, rewriting of the EEPROM 33 will be explained.

A program for performing this rewriting is stored in the PROM 31 in advance. Possible methods for starting this rewriting program include, for example, turning on the power while pressing any switch on the operation panel 11, or inputting a predetermined command for rewriting from the host computer 27. When this rewriting program is started, it enters a rewriting mode, takes in data of a new control program part from the host computer 27, and stores it in the RAM 35. This mode continues until a certain amount of data (for example, 256K bits) is received, and then the RAM3
Check whether the data in 5 is correct. This check is performed, for example, by checking whether the applicable model name and version name written in a predetermined location of the program part are appropriate. When the check is completed, RAM3
Write the data of 5 to EEPROM33. This completes the rewriting.

[0033] Note that the program data to be rewritten is
In addition to checking the above, the reason for storing it in 35 is for EE
Since the write speed of the PROM 33 is slower than the data input speed from the host, this is to prevent data in the EEPROM 33 from being needlessly destroyed in the event of a communication error or the like.

[0034]

[Effects of the Invention] As explained above, according to the present invention,
Among the control programs, the parts that include programs that are forced to change due to changes in the control code system and do not include programs for controlling mechanisms are stored in electrically rewritable nonvolatile memory, so different control code systems can be used. It is easy to deal with this problem, and safety is guaranteed even if a mistake occurs in rewriting.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall hardware configuration of a printer according to the present invention.

FIG. 2 is a memory mapping diagram in the embodiment of FIG. 1;

FIG. 3 is a block diagram showing the functions realized by the control program in the embodiment of FIG. 1, together with the relationship with hardware.

FIG. 4 is a flowchart showing an example of the operation of the embodiment of FIG. 1;

FIG. 5 is a flowchart showing another example of the operation of the embodiment of FIG. 1;

FIG. 6 is a flowchart showing yet another example of the operation of the embodiment of FIG. 1;

FIG. 7 is a flowchart showing yet another example of operation of the embodiment of FIG. 1;

[Explanation of symbols]

9 Printer mechanism 11 Operation panel 23 CPU 31 Program PROM 33 Program EEPROM

Claims (5)

[Claims] Claim 1: A control program stored in advance is transmitted to a CPU.
A printer that controls a printer mechanism by executing it in response to a control code given from the outside, the control program includes a program that is forced to be changed due to a change in the system of the control code, and that controls the control of the printer mechanism. a non-volatile first program memory that stores a first part that does not include a program for the control program; and a non-volatile first program memory that stores a second part that is a part of the control program excluding the first part. a second program memory, the first program memory being electrically rewritable. 2. The printer according to claim 1, wherein the C
A printer characterized in that a program start address of a PU is allocated to the second program memory. 3. The printer according to claim 1, wherein the second portion of the control program includes a rewriting program for causing the CPU to rewrite the first program memory. A printer characterized by: 4. The printer according to claim 2, wherein the C
A printer comprising an operation switch for giving a predetermined command to a PU, wherein the rewriting program is started by a predetermined operation of the operation switch. 5. The printer according to claim 2, wherein the rewriting program is activated by inputting a predetermined code as the control code from the outside.