JPH0427577B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] In the present invention, when a parity error is detected when reading a memory data area, the host side is requested to resend the data, and the data sent from the host side is The present invention relates to an automatic correction method for memory data errors in which new identical data is written in a memory data area.

[Conventional technology and problems]

In printers that have CS (control memory) and CG (character generator) in their memory, when the printer is powered on, the control program and character patterns are set in the CS and CG by the host CPU. It will be uploaded. Thereafter, when the print data is sent from the host CPU to the printer device, the print data is processed under the control of the control program, and character patterns are read out from the CG and printed out. However, if a failure such as a parity error occurs when reading such CS or CG, the printer device will not be able to perform correct control and printing. Conventionally, when a parity error occurs, the hardware ECC (Error
Checking and Correction) function attempts to correct and recover data.

[Purpose of the invention]

The present invention is based on the above considerations, and includes:
Memory data errors using microcontrol that can correct and recover data when a parity error occurs during memory read, without requiring any hardware such as an ECC function. The purpose is to provide an automatic correction method for

[Structure of the invention]

To this end, the automatic correction method for memory data errors of the present invention includes a memory including a control memory and a character generator that respectively store a control program and a character pattern sent from a host computer when the device is started up; a control unit for developing character codes sent from a computer into character patterns by the character generator for each character code under the control of the control program and writing them into an image memory; An output station that has an output mechanism that visually outputs stored character patterns, a buffer memory for temporarily storing characters retransmitted from the host computer, and each character code sent from the host computer. If a parity error is detected when reading the corresponding character pattern from the character generator, the character code corresponding to the character pattern data in which the parity error was detected is sent to the host computer and the character pattern means for requesting retransmission of data; and means for storing character pattern data retransmitted from the host computer based on the request in the buffer memory; The character pattern data stored in the buffer memory is stored in the image memory in place of the detected character pattern, and after the writing of the character pattern in the image memory is completed, the character pattern data is stored in the buffer memory. The invention is characterized in that a character pattern created by the character generator is stored in the character generator.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In Figure 1, 1 is the host CPU, 2 is the document printer station, 3 is the file, 4 is the WSC (Work Station Channel),
5 is a serial interface controller, 6 is a buffer, 7 is a memory, and 8 is an image controller.
A memory, 9 a processor, and 10 a printer controller.

In Figure 1, host CPU 1 and document printer station 2 are
The WSC 4 and the serial interface controller 5 are connected by a serial interface. The document printer station 2 includes a buffer 6, a memory 7, an image memory 8, a printer controller 10, and a processor 9 for controlling these. Memory 7 contains CS (control memory) and CG.
(Character Generator), which stores control programs for the document printer station and various character patterns developed in the image memory 8. The contents of these CS and CG are set up by the host CPU 1 when the document printer device is powered on. After that, in order to print the data of each character on a certain paper, when the print data is sent from the host CPU 1, the print data is stored in the buffer 6 through the serial interface controller 5 in the document printer station 2. Ru. And Batsuhua 6
The character code of the print data stored in (for example
The CG in the memory 7 is accessed according to the JIS code), and a character pattern of dot images corresponding to the character code is developed in the image memory 8.
The printer controller 10 uses this image
The printing mechanism is controlled according to the character pattern developed in the memory 8.

The present invention corrects the data when a parity error is detected in the data read from the memory 7 when the processor 9 processes the print data sent from the host CPU 1 under the control of the control program. , which guarantees the data.
When CS and CG are set up at power-on, parity is generated, and when read, a parity check is performed, and these are implemented by hardware. When a parity error is detected in the read data, an interrupt is generated in the processor 9. The processor 9 uses the CS of the memory 7 based on the processing status of the program.
It recognizes which part of the CG is being accessed, and if it is a CG, which JIS code the parity error occurred in, and requests the host CPU to retransmit the data in which the parity error occurred.
In the host CPU 1, the WSC 4 accepts a data retransmission request from the document printer station 2, and the retransmission process is performed by the firmware of the WSC 4, regardless of the OS (operation system) of the host CPU 1. At Document Printer Station 2, the host
Print data is processed based on new data sent from the CPU 1, and then the new data is written into the memory 7.

The specific flow of processing when a parity error occurs will be explained with reference to the diagrams shown in FIG. These processing flows are realized by a processor executing a control program (microprogram).

A (A) data read command is issued from the processor 9 to the memory 7.

(A) A parity error is detected in the data.

, from the processor 9 to the host CPU through the serial interface controller 5.
Data is requested for 1. The data request can be e.g.
In the case of CG, it is determined by JIS code, and in the case of CS, it is determined by the cylinder address registered in file 3 of host CPU1.

, The host CPU 1 performs (A) data extraction. This process is performed by the WSC4 firmware.

(A) Data is sent from WSC4 of host CPU1.

The (A) data sent via the serial interface is stored in the buffer 6 via the serial interface controller 5.

After the print data including the character pattern stored in the buffer memory 6 is expanded into the image memory 8, the processor 9 writes the new (A) data stored in the buffer 6 to the memory 7. be included. By this,
For parity error detection (A) data,
This means that the contents of the memory 7 have been rewritten with new, identical data.

Note that by logging memory data errors in the microcontroller, it is possible to know the error occurrence status.

[Invention effect]

As is clear from the above description, according to the present invention, when a parity error is detected in a character pattern, the host CPU is requested to resend the character pattern of the same character type and the data is corrected. Hardware such as an ECC circuit for correction can be omitted, and the device can be simplified. Furthermore, in the present invention, only the character pattern in which a parity error has occurred is requested to be retransmitted, and only the corresponding character pattern is retransmitted, so the transfer time can be shortened and the influence on other processes can be reduced. I can do it.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. 1...Host CPU, 2...Document printer station, 3...File, 4...
WSC (Work Station Channel), 5... serial interface controller, 6... buffer, 7... memory, 8... image memory, 9... processor, 10... printer controller.

Claims (1)

[Claims] 1. A memory including a control memory and a character generator that respectively store a control program and a character pattern sent from a host computer at the time of startup of the device, and a character generator that stores a control program and a character pattern sent from the host computer. a control unit that expands each character code into a character pattern by the character generator and writes it into an image memory under the control of the control program; and a control unit that visually outputs the character pattern stored in the image memory. An output station having an output mechanism includes a buffer memory for temporarily storing character patterns retransmitted from the host computer, and a character pattern corresponding to each character code sent from the host computer.・If a parity error is detected when reading from the generator, means for sending a character code corresponding to the character pattern data in which the parity error has been detected to the host computer to request retransmission of the character pattern data; , means for storing the character pattern data retransmitted from the host computer based on the request in the buffer memory, and under the control of the control unit, the character pattern data in place of the character pattern in which the parity error was detected is provided. The character pattern data stored in the buffer memory is stored in the image memory, and after writing of the character pattern to the image memory is completed, the character pattern data stored in the buffer memory is transferred to the character generator. An automatic correction method for memory data errors characterized by storing data in the memory.