JPH05100803A - Plural port printer controllers and its control system - Google Patents

Abstract

PURPOSE:To efficiently use buffer memories corresponding to plural host devices between the host devices in a printer controller having an interface with the host devices. CONSTITUTION:A central processing unit 5 allocates the areas 7 and 8 of a device corresponding memory 6 to the concerned host devices in accordance with area size instructions from the host device 1 or 2. Thus, the respective host devices 1 and 2 operate in such a way that the capacity of the buffer memories are apparently enlarged. When the other host device intends to use the areas 7 and 8 which a certain host device uses, a request and permission against alteration are transmitted and received between the host devices, and a new area size instruction is transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-port printer controller which has an interface with a plurality of host devices and prints data from designated host devices.

[0002]

2. Description of the Related Art A conventional multi-port printer controller stores data from a plurality of host devices in a device memory corresponding to each host device, and the data stored in the device memory corresponds to one page of printing paper. It was supposed to print sequentially from the point when it reached.

The above-mentioned conventional technique will be described with reference to FIG.
In FIG. 2, reference numerals 21 and 22 are host devices that transmit data to be printed. Reference numeral 4 is an interface circuit for receiving data from the higher-level devices 21 and 22. 26 is a device-compatible memory, which is an area 27 for storing data from the higher-level device 21.
And an area 28 for storing data from the host device 22. The size of the areas 27 and 28 is one page of printing paper. A central processing unit 25 stores the data received by the interface circuit 4 in the area 27 or the area 28 in association with the host device 21 or 22.
A printing mechanism 9 prints the data stored in the area 27 or the area 28. 23 is an interface circuit 4, a central processing unit 25, a device corresponding memory 26,
A multi-port printer controller including a printing mechanism 9. In this example, the number of host devices is two.

Here, it is assumed that the upper device 21 or 22 starts data transmission. The central processing unit 25 takes out the data from the interface circuit 4 and stores the data from the host device 21 in the area 27 and the data from the host device 22 in the area 28. The data is sequentially stored, and when the area 27 is full, for example, when one page of printing paper is reached, the central processing unit 25 commands the printing mechanism 9 to print the data in the area 27. Printing mechanism 9 is in area 27
Until the end of printing the data of
Since the next data transmitted from the host device 21 cannot be stored, the host device 21 waits until the area 27 becomes available.
That is, the data cannot be transmitted until the data in the area 27 is printed, and the standby state is set.

[0005]

In this conventional multi-port printer controller, when an area in the device memory corresponding to each host device becomes full, the host device corresponding to the area is completed until printing of the area is completed. However, there is a problem in that it becomes impossible to transmit data, which hinders the processing of the host device.

[0006]

A multi-port printer controller of the present invention is a multi-port printer controller which has an interface with a plurality of host devices and stores and prints data from each host device. A device-corresponding memory that stores the data received from the device in a region allocated to each host device, and a region allocated to each host device in the device-corresponding memory according to a region size command received from each host device. Is provided with a means for changing the size of the.

According to the control system for a multi-port printer controller of the present invention, in a plurality of host devices connected to the above-configured multi-port printer controller, each of the host devices in the device corresponding memory is assigned by the area size command. When changing the size of the area, the plurality of higher-level devices are allowed to change each other.

[0008]

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

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 1 and 2 are host devices. 4 is an interface circuit. 5 is a central processing unit. Reference numeral 6 denotes a device-compatible memory, which is data from the higher-level device 1 or higher-level device 2
Area 7 and area 8 for storing either one of the data from. The size of each of the areas 7 and 8 is one page of printing paper. 9 is a printing mechanism. 3 is an interface circuit 4 and a central processing unit 5
A multi-port printer controller including a device-compatible memory 6 and a printing mechanism 9. The interface circuit 4 is connected to the host device 1 by the data signal line 10, and is also connected to the host device 2 by the data signal line 11. The central processing unit 5 uses the data signal line 12 for the interface circuit 4, the device-corresponding memory 6, and the printing mechanism 9.
Connected to.

Information required for print control can be transmitted and received between the upper level devices 1 and 2 through the data signal line 15.

Next, the operation of the multi-port printer controller 3 will be described. Here, it is assumed that the higher-level device 2 does not operate and therefore does not hold the data to be printed, while the higher-level device 1 holds the data to be printed.

Since the higher-level device 1 can exclusively use the multi-port printer controller 3, first, an area size command for securing the device-compatible memory 6 for two pages is transmitted. The area size command uses a code that is not defined as a character code for printing. When the central processing unit 5 reads the data sent from the higher-level device 1 from the interface circuit 4 and decodes that this specifies the reservation of the device-corresponding memory 6 for 2 pages by the area size command, the area 7 Area 8 and host device 1
Assign to. As a result, the data from the host device 1 is stored in the area 7, and when the area 7 is full, the central processing unit 5 commands the printing mechanism 9 to print the data in the area 7. At this time, when data is subsequently transmitted from the higher-level device 1, the central processing destination 5 stores this in the area 8 and when the area 8 is full, the central processing destination 5 sends the area 8 to the printing mechanism 9.
Command to print the data. After that, similarly, if the printing of the data in the area 7 is completed, the data is stored in the area 7 and printed. However, if the data in the area 7 is still being printed, the host device 1 waits for data transmission.

When the host device 2 which is not currently operating operates and tries to transmit data, if the device-corresponding memory 6 cannot be secured, data transmission is waited. That is, in this case, the higher-level device 1 waits until the higher-level device 1 sends out a new area size command to free up the device-corresponding memory 6 for one page or more.

Next, the operation when the area sizes of the device-corresponding memory 6 are mutually adjusted between the upper level devices 1 and 2 will be described. Similarly to the above, the host device 2 is not operating,
It is assumed that the higher-level device 1 holds print data. The process in which the higher-level device 1 secures the areas 7 and 8 and prints is the same as above.

Here, it is assumed that the higher-level device 2 operates and tries to print. The higher-level device 2 first requests the higher-level device 1 to secure the device-compatible memory 6 via the data signal line 15. Thereby, the higher-level device 1 transmits an area size command in order to pass the device-corresponding memory 6 for one page, for example, to the higher-level device 2. Receiving this instruction, the central processing unit 5 assigns either the area 7 or the area 8 where the printing mechanism 9 has finished printing to the higher-level device 2 and the other to the higher-level device 1. As described above, it becomes possible for both of the upper level devices 1 and 2 to transmit print data.

[0016]

As described above, in the multi-port printer controller of the present invention, an unused area in the device-corresponding memory is arbitrarily allocated to the host device by the area size command. Since it can be used efficiently and the memory corresponding to the device can be apparently enlarged, it is effective in reducing the wait for the host device to transmit the data until the data in the area is printed.

Further, since the device corresponding memory of the multi-port printer controller can be allocated among the plurality of host devices, one host device does not keep monopolizing the multi-port printer controller. There is an effect that the multi-port printer controller can be used more efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional multi-port printer controller.

[Explanation of symbols]

 1,2,21,22 Upper device 4 Interface circuit 5,25 Central processing unit 6,26 Device compatible memory 7, 8, 27, 28 Area 9 Printing mechanism

Claims (2)

[Claims] 1. A multi-port printer controller having an interface with a plurality of higher-level devices and storing and printing data from the respective higher-level devices, wherein data received from the respective higher-level devices is assigned to the respective higher-level devices. A device-corresponding memory to be stored in the region; and means for changing the size of the region allocated to each of the host devices in the device-corresponding memory according to a region size command received from each of the host devices. And a multi-port printer controller. 2. A plurality of host devices connected to the multi-port printer controller according to claim 1, wherein the size of an area assigned to each host device in the device corresponding memory is changed by the area size command. In this case, the control method of the multi-port printer controller is characterized in that the plurality of higher-level devices are allowed to change each other first.