JPS6316767B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print data transfer system in printing devices such as line printers and typewriters.

Conventionally, in line printers, etc., print data is transferred line by line from the central processing unit and printed. For example, when printing a slip, the slip includes the slip name, notes, etc. There is a fixed part and a variable part that prints the amount, etc., and in the past, all of this data was transferred from the central processing unit every time it was printed, resulting in a long channel exclusive time.

For this reason, conventional methods shorten the exclusive time of a channel by transferring only variable data after storing fixed data (Japanese Patent Application Laid-open No.
88129), but the conventional structure generally consisted of a memory for storing fixed data and variable data, and a memory for storing the contents stored in the memory. This has caused problems such as the need for accessing each memory.

The present invention aims to eliminate such drawbacks, and the purpose is to divide the buffer memory of a printing device into a fixed data area and a variable data area,
After fixed data from the central processing unit is stored in the fixed data area, only variable data is transferred from the central processing unit and stored in the variable data area. When transferring print data for the first time, a bit indicating the fixed area or the variable data area is written in control bit CB ₁₁ in the buffer memory, and a bit indicating a delimiter of the transferred print data is written in control bit CB ₁₂ . ,
In a print data transfer method in a printing device, the control bit CB ₁₁ is read out sequentially and the variable data is written in the buffer memory according to the read value when transferring print data from next time onwards. It is achieved by doing so.

Hereinafter, the present invention will be explained based on examples.

FIGS. 1a and 1b are diagrams showing an overview of the present invention,
CPU is a central processing unit, LP is a line printer device, CH is a channel, and BF ₁ to _{BF 3} are buffer memories. Also, the "x" mark is a fixed data section, and the "□" mark is a variable data section.

In the present invention, when the print data is transferred for the first time, fixed data and invalid data indicating a variable data area are transferred, and from the second time onward, only the variable data is transferred as print data.

A specific example will be explained with reference to FIG.

The figure shows an example using two buffer memories, and while writing data to one buffer memory,
The data in the other buffer memory is read and printed.

In the figure, CCT is the channel interface controller, CJ is the character judgment circuit, BF ₁₁ ,
BF ₁₂ is a buffer memory, CONT ₁ and CONT ₂ are buffer memory counters, BCONT is a buffer memory controller, and PCT is a print controller.

Buffer memories BF ₁₁ and BF ₁₂ are provided with control bits CB ₁₁ , CB ₁₂ , CB ₂₁ and CB ₂₂ ,
Control bits CB ₁₁ and CB ₂₁ are written with bits indicating a fixed data area or variable data area, and control bits CB ₁₂ and CB ₂₂ are written with bits indicating a delimiter of transferred print data.

The circuit operation will be explained below.

When a page image setting command is given to the line printer device LP from the channel CH, the buffer memory controller BCONT sets buffer memory counters CONT ₁ and CONT ₂ to “0” and requests data transfer to the channel interface controller CCT. do.

The data sent from channel CH is transferred to character determination circuit CJ, where it is determined whether or not it is invalid data.

That is, since invalid data is transferred from the central processing unit CPU to the portion indicating the variable data area, the character determination circuit CJ is caused to perform the above determination.

If it is fixed data, set control bit CB ₁₁ to "1", write the data to buffer memory BF ₁₁ , and write the data to buffer memory counter CONT _1.
Add +1 to If the data is invalid data indicating a variable data area, the control bit _CB11 is set to "0" and the buffer memory counter _CONT1 is incremented by one. When one more line of data is stored, control bit CB ₁₂ is set to "1".

To explain the above using Figure 1b, b
For example, the lines of the slip shown in the figure can be buffered.
When storing in BF ₁₁ , the fixed data area “×××
×” Data to be printed in buffer memory BF ₁₁
Then, data indicating the variable data area "□" (invalid data) is stored at address 2 of buffer memory BF ₁₁ (control bit CB ₁₁ ).
Finally, the fixed data area “×××××
×” Data to be printed in buffer memory BF ₁₁
At this time, the control bit is stored at address 3.
Set CB ₁₂ to “1”.

Repeat the above explanation to create a buffer memory.
Initial writing of data to be stored in BF ₁₁ is performed.

Next, storage of data from the second time onward will be explained.

From the second time onward, only the variable data is transferred, so it is necessary to search and store the area where the invalid data was stored the first time.

Therefore, when a print command is received from the channel CH, the buffer memory controller BCONT requests data transfer from the channel interface controller CCT and sets the buffer memory counter CONT ₁ to "0".

The print data transferred from the channel CH and passed through the channel interface controller CCT is judged by the character judgment circuit CJ as described above to determine whether it is invalid data or not. If it is invalid data, an error is sent to the channel interface controller CCT. Report will be made at (This is because the print data transferred from the second time onward is determined to be variable data, so if invalid data is still transferred from the second time onward, there may be a failure in the peripheral circuit, etc.) ) If the value read from control bit CB ₁₁ is “1”, the buffer memory counter
CONT ₁ +1 and control bit CB ₁₁ again
and the read control bits.
Do the above until CB ₁₁ becomes “0”,
When control bit _CB11 becomes "0", data is written to buffer memory _BF11 .

When the value of the buffer memory counter CONT ₁ becomes the same value as when setting the page image, a printing command is issued to the print controller PCT.

The print controller PCT sets the value of the buffer memory counter CONT ₁ to "0" and sequentially reads out the contents of the buffer memory BF ₁₁ to perform printing.

Print controller PCT has buffer memory
When a print command is received from channel CH while reading BF ₁₁ , data is written to buffer memory BF ₂₂ in the same manner as buffer memory BF ₁₁ .

When printing, if for some reason the value of the buffer memory counter becomes larger than when the page image was set, the in-collect length is reported to the channel CH, and the channel CH determines that the contents of the buffer memory are incorrect. and stop printing.

Conversely, if the value of the buffer memory counter is smaller than when the page image was set, the variable data area is cleared or characters such as asterisks are written and printed.

As described above, according to the present invention, only variable data is transferred after the page image is set, so the exclusive time of the channel is shortened, and
Since the memory only needs to be accessed once,
It is expected that the processing time of the entire printing device will be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an outline of the present invention, and FIG. 2 is a diagram showing a specific example. In the figure, CPU is the central processing unit, CH is the channel,
LP is line printer device, BF ₁₁ , BF ₁₂ are buffer memory, BCONT is buffer memory controller, PCT is print controller, CONT ₁ ,
CONT ₂ is a buffer memory counter, CCT is a channel interface controller, and CJ is a character judgment circuit.

Claims (1)

[Claims] 1. After dividing the buffer memory of the printing device into a fixed data area and a variable data area, and storing fixed data from the central processing unit in the fixed data area,
In a print data transfer method in a printing device that transfers only variable data from the central processing unit and stores it in the variable data area, when the print data is transferred for the first time, the control bit CB ₁₁ in the buffer memory is set to the fixed value. In addition to writing a bit indicating the data area or the variable data area, a bit indicating the delimiter of the transferred print data is also written in control bit CB ₁₂ , and when transferring print data from the next time onwards, the control bit CB ₁₁ is sequentially written. 1. A print data transfer method in a printing device, characterized in that the variable data is read and written in the buffer memory according to the read value.