JP2002041269A - Printer, method of controlling printer and recording medium recorded program therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce CPU's load during the process which stores received data on receiving buffer. SOLUTION: In the case that any receiving error exists on the received data, the received data producing receiving error are canceled and replace it with an error letter '*' in an data receiving process to a serial interface circuit 20 which is executed on a CPU 60. And the error letter '*' is output from the interface circuit 20 as print data. Thus the data, which is output from the interface circuit 20, can be stored on the receiving buffer 49 by just transferring it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, a method of controlling the printer, and a recording medium on which a program for recording the program is recorded, and more particularly to a printer having a function of transferring received data received by an interface circuit to a receiving buffer. The present invention relates to a method for controlling a printer and a recording medium on which a program for the method is recorded.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an internal hardware configuration of a conventional printer 100. As shown in FIG. 5, the printer 100 includes a serial interface circuit 110 and a CPU (Central Processing Unit).
t) 112, the reception buffer 114, and the print execution unit 11
6 is provided.

A serial signal as printing data is input to a serial interface circuit 110 from a computer connected to the printer 100. The received data received by the serial interface circuit 110 is transferred to the reception buffer 114 via the CPU 112 as print data.

That is, when the serial interface circuit 110 normally receives data for printing,
One byte of data is stored in the transfer register as received data, and a data ready interrupt request is output to the CPU 112. The CPU 112 starts transfer processing based on the data ready interrupt request, reads one byte of received data stored in the transfer register, and transfers the read data to the reception buffer 114 as print data.

However, the serial interface circuit 1
In 10, there may be cases where the received data is not normally received. For example, as a result of determining the presence or absence of an error based on the parity bit added to the received data, it may be found that the received data has an error. That is,
In the serial interface circuit 110, a parity error may occur. Further, upon receiving the received data, the capacity of the received frame may be exceeded, and a frame overrun error may occur.

When such a reception error occurs, the serial interface circuit 110 stores the reception data in the transfer register and transmits a data ready interrupt request and a reception error interrupt request to the CPU 112. Here, the reception error interrupt request has a higher interrupt priority than the data ready interrupt request. Therefore, the CPU 112 performs a process based on the reception error interrupt request. Specifically, the received data of one byte in which the reception error has occurred is discarded and replaced with the error character “*” which is the substitute print data. Then, the error character “*” is stored in the reception buffer 114 as print data for printing.

[0007] The print execution unit 116 receives the
14 is sequentially read out and the actual printing is performed.

[0008] To explain one example, for example, "PEN"
When the reception data to be printed is normally received by the interface circuit 110, the print execution unit 116
Since the print data “PEN” is stored in the reception buffer 114, the print “PEN” is executed.
On the other hand, for example, if any reception error occurs when “E” of “PEN” is received by the interface circuit 110, the print data “P * N” is stored in the reception buffer 114, so The part 116 has “P *
N ".

The process of storing the above-mentioned received data as print data in the receive buffer will be described in detail. First,
Based on FIG. 6, the serial interface circuit 110
Will be described in detail. This data receiving process is realized in the form of a data receiving task, and the CPU 112 executes the data receiving task.

As shown in FIG. 6, in the data receiving process,
First, it is determined whether any reception error has occurred (step S100). If no reception error has occurred (step S100: No), the received data of one byte is output (step S101). That is, it stores the received data for one byte in the transfer register and outputs a data ready interrupt request to the CPU 112. Thus, the data receiving process ends.

On the other hand, if a reception error has occurred (step S100: Yes), a reception error interrupt request is output to the CPU 112 (step S102). Subsequently, one byte of received data is output to the CPU 112 (step S101). That is, it stores the received data for one byte in the transfer register and outputs a data ready interrupt request to the CPU 112. This allows
This data reception processing ends.

Next, the error transfer process performed by the CPU 112 will be described in detail with reference to FIG. The error transfer process is realized in the form of an error transfer task, and the CPU 112 executes the error transfer task. The error transfer process is an interrupt process started by an interrupt controller (handler) when the serial interface circuit 110 outputs a reception error interrupt request.

As shown in FIG. 7, the CPU 112 reads one byte of received data from the transfer register (step S110). Subsequently, the CPU 112 discards the received data of one byte (step S111).

Next, the CPU 112
4 is written with an error character "*" (step S11).
2). Subsequently, the data ready interrupt request is cleared (step S113).

[0015]

As can be seen from the above description, in the conventional printer 100, the received data received by the serial interface circuit 110 is transferred to the receiving buffer 114 via the CPU 112 as print data. Was. However, the CPU 112
Since many processes other than these receiving processes have to be performed, it is desirable to reduce the load as much as possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been developed in consideration of the above-described problem. It is an object of the present invention to simplify the data transfer from the interface circuit to the reception buffer by outputting the received data after replacing it with the error identification information.

[0017]

In order to solve the above-mentioned problems, an interface circuit according to the present invention for receiving external print data as reception data, and an interface circuit for receiving reception data received by the interface circuit. When an error has occurred, the reception data in which the reception error has occurred is replaced with error identification information, and then output as print data from the interface circuit. And receiving data output means for outputting the received data as print data from the interface circuit when no reception error has occurred in the data. Thus, the data output from the interface circuit can be used as the print data on which the replacement process for the reception error has been performed.

[0018] Further, a transfer means for transferring the print data output from the interface circuit to a reception buffer may be provided. In this case, it is sufficient for the transfer means to simply transfer the print data subjected to the replacement process for the reception error to the reception buffer.

For this reason, the transfer means is a direct
It is also possible to configure with a memory access controller, and the addition of an arithmetic processing unit can be reduced. However, the transfer means may be a task executed by an arithmetic processing device.

Further, the error identification information is stored in a replacement register in the interface circuit, and the replacement output means acquires the error identification information from the replacement register when a reception error occurs. Good.

Further, the error identification information may be constituted by a specific character of one byte. This allows the user to print specific characters,
It becomes possible to know that a reception error has occurred.

Further, the reception error may be an error that occurs when the reception data has a data error. If there is a data error in the received data, the received data cannot be trusted. Therefore, by replacing the received data with error identification information, the user can be notified that a reception error has occurred.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, when a reception error occurs when print data is received, the corresponding character is replaced with "*" by a serial interface circuit,
The print data is stored in a reception buffer by DMA transfer. And this gives C
The reception data can be stored in the reception buffer as print data without the intervention of the PU. This will be described in more detail below.

FIG. 1 is a block diagram showing a hardware configuration of a printer 10 according to one embodiment of the present invention. As shown in FIG. 1, the printer 10 includes a serial interface circuit 20 and a DMA (Direct Memory Acceses).
s) Controller 30, reception buffer 40, print execution unit 50, CPU (Central Processing Unit) 60
And are provided. The CPU 60 constitutes an arithmetic processing device according to the present embodiment.

The serial interface circuit 20 includes:
Printing data is input from a computer (not shown). In the present embodiment, the print data is input to the serial interface circuit 20 as a serial data signal.

If the print data input to the serial interface circuit 20 is normally received, the received data is used as print data in a DMA reception process for controlling the serial interface circuit 20.
Sent to controller 30. That is, after one byte of received data is stored in the transfer register as print data, a data ready interrupt request is output to the DMA controller 30.

On the other hand, the serial interface circuit 20
If any reception error occurs in the print data input to the printer, the received data corresponding to one byte is replaced with the error character stored in the replacement register 22 in the data reception processing for controlling the serial interface circuit 20. After the replacement, the data is output to the DMA controller 30 as print data. In the present embodiment, “*” is stored in the replacement register 22 as an error character. Therefore, “*” is stored in the transfer register as one-byte print data, and then a data ready interrupt request is output to the DMA controller 30.

The DMA controller 30 is a controller for realizing direct memory access which enables memory access without the intervention of the CPU 60. Therefore, D which receives the data ready interrupt request
The MA controller 30 fetches one byte of print data from the transfer register, and
To be stored. The print execution unit 50 sequentially reads out the print data stored in the reception buffer 40, performs a necessary language interpretation, develops the image into a bit image, and drives a print head to actually print a print sheet. Print on.
The control and processing required to perform this printing are performed by the CPU 60.
Executed in

Next, the data reception processing performed by the serial interface circuit 20 will be described in detail with reference to FIG. The data receiving process is realized in the form of a data receiving task, and the CPU 60 executes the data receiving task.

As shown in FIG. 2, in the data receiving process,
First, it is determined whether any reception error has occurred (step S10). If no reception error has occurred (step S10: No), the received data of one byte is output to the DMA controller 30 (step S11). That is, the print data for one byte is stored in the transfer register, and a data ready interrupt request is output to the DMA controller 30. Thus, the data receiving process ends.

On the other hand, if a reception error has occurred (step S10: Yes), the received data of one byte is discarded and replaced with the error character "*" stored in the replacement register 22 (step S12). ). And
This replaced error character "*" is used as print data in D
Output to MA controller 30 (step S11).
That is, the error character "*" is stored in the transfer register as print data, and a data ready interrupt request is output to the DMA controller 30. Thus, the data receiving process ends.

Next, the transfer process performed by the DMA controller 30 will be described in detail with reference to FIG. FIG. 3 is a flowchart for explaining the transfer processing performed by the DMA controller 30, and is executed without involving the CPU 60. This transfer process is started when the DMA controller 30 receives a data ready interrupt request from the serial interface circuit 20.

As shown in FIG. 3, the DMA controller 3
0 indicates that the print data stored in the transfer register is 1
The bytes are read (step S20). And DMA
The controller 30 sends the print data to the reception buffer 4
Write to 0 (step S21). Thus, the transfer process ends.

As described above, according to the printer 10 of the present embodiment, when a reception error occurs in the reception data in the data reception processing for controlling the serial interface circuit 20, the corresponding character is
Since the error character "*" has been replaced, the printer 10 simply stores the data output in this data reception process as print data in the reception buffer 40.

Therefore, data transfer from the serial interface circuit 20 to the reception buffer 40 can be performed by DMA transfer by the DMA controller 30.
As described above, the DMA transfer enables the CPU 60
Need not be involved in this data transfer.
0 can be reduced.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, the case where the printer 10 has the serial interface circuit 20 has been described as an example. However, the present invention can be applied to a printer having another interface circuit such as a parallel interface circuit which may cause some reception error. The same applies. For example, from the computer to the printer 1
The data signal input to 0 has a parity bit, which can be applied to a printer having a parallel interface circuit in which a parity error can occur.

Further, in the above-described embodiment, the data transfer from the serial interface circuit 20 to the reception buffer 40 is performed by the DMA controller 30, but by configuring the printer as shown in FIG.
The task may be performed by the CPU 60. Further, in the above-described embodiment, even when a reception error occurs, the serial interface circuit 2
Although the reception error interrupt request is not transmitted from 0 to the DMA controller 30, the reception error interrupt request may be transmitted.

Further, in the above-described embodiment, when a reception error occurs, an error character "*" is printed as error identification information to be printed instead of the received data. You may make it print.

The data reception processing of FIG. 2 described in the above embodiment and the transfer processing of FIG.
In the case of realizing as the process executed in 60,
Programs for executing these processes are stored on a floppy (registered trademark) disk, CD-ROM (Compact Disc-R
It can be recorded on a recording medium such as an ead only memory (ROM), a ROM, or a memory card and distributed in the form of a recording medium. In this case, the above-described embodiment can be realized by causing the printer 10 to read the recording medium on which the program is recorded and to execute the program.

The printer 10 may include another program such as an operating system or another application program. In this case, the printer 10
By utilizing another program included in the printer 10, an instruction to call a program for realizing the same processing as that of the present embodiment from among the programs included in the printer 10 may be recorded on the recording medium.

Further, such a program can be distributed not as a recording medium but as a carrier through a network. The program transmitted on the network in the form of a carrier wave is taken into the printer 10, and the above-described embodiment can be realized by executing the program.

Further, when a program is recorded on a recording medium or transmitted as a carrier wave over a network, the program may be encrypted or compressed.
In this case, the printer 10 that has read the program from the recording medium or the carrier wave needs to execute the program after decoding and decompressing the program.

[0043]

As described above, according to the present invention,
When a reception error occurs, the print data in which the reception data is replaced with the error identification information is output from the interface circuit, so that the process of storing the data output from the interface circuit in the reception buffer can be simplified. .

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating the contents of a data reception process performed on a serial interface circuit.

FIG. 3 is a flowchart illustrating the contents of a transfer process executed by a DMA controller.

FIG. 4 is a diagram showing a modification of the present invention.

FIG. 5 is a block diagram illustrating a hardware configuration of a conventional printer.

FIG. 6 is a flowchart illustrating the contents of data reception processing for a serial interface circuit, which is executed by a conventional printer.

FIG. 7 is executed by a CPU in a conventional printer;
FIG. 6 is a flowchart illustrating the contents of an error transfer process.

[Explanation of symbols]

 10 Printer 20 Serial Interface 22 Replacement Register 30 DMA Controller 40 Receive Buffer 50 Print Execution Unit 60 CPU

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C061 AP01 HH01 HJ06 HV05 HV40 HV47 2C087 AB05 BD01 BD41 BD46 BD53 5B021 AA01 BB01 BB10 DD01 NN16

Claims (9)

[Claims] An interface circuit for receiving print data from the outside as received data, and in the case where any received error occurs in the received data received by the interface circuit, the reception in which the reception error has occurred. Replacing the data with the error identification information and outputting the print data as print data from the interface circuit; and replacing the received data received by the interface circuit if no reception error has occurred. A receiving data output unit that outputs data from the interface circuit as print data. 2. The printer according to claim 1, further comprising a transfer unit that transfers the print data output from the interface circuit to a reception buffer. 3. The printer according to claim 2, wherein said transfer means is a direct memory access controller. 4. The printer according to claim 2, wherein said transfer means is a task executed by an arithmetic processing unit. 5. The method according to claim 1, wherein said error identification information is stored in a replacement register in said interface circuit, and said replacement output means acquires error identification information from said replacement register when a reception error occurs. The printer according to any one of claims 1 to 4, wherein 6. The apparatus according to claim 1, wherein the error identification information is composed of a specific character of one byte.
A printer according to any one of claims 5 to 5. 7. The printer according to claim 1, wherein the reception error is an error that occurs when there is a data error in the reception data. 8. A control method of a printer having an interface circuit for receiving print data from the outside as reception data, wherein when any reception error occurs in the reception data received by the interface circuit. Replacing the reception data in which the reception error has occurred with error identification information and outputting the print data as print data from the interface circuit; anda reception error occurs in the reception data received by the interface circuit. A receiving data output step of outputting the received data as print data from the interface circuit when there is no printer data. 9. A recording medium on which a program for controlling a printer having an interface circuit for receiving external print data as received data is recorded, wherein the received data received by the interface circuit is stored in a storage medium. When any reception error has occurred, the reception data in which the reception error has occurred is replaced with error identification information, and then output as print data from the interface circuit. A receiving data output step of outputting the received data as print data from the interface circuit when a reception error does not occur in the received data, wherein a program is recorded.