JPH0150938B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention outputs updated identifier information onto a data bus each time an identifier section of a board issues a read command specifying the identifier section. This paper relates to an automatic board identification system that has become popular.

〔overview〕

Adding an identifier output function and a function to update the identifier information each time a read command to read the identifier is issued to the identifier section of the board allows the program to issue the read command multiple times to read the identifier. This is an automatic board identification method that identifies the type of board using an identifier information string.

[Conventional technology and problems]

Conventionally, a program reads and identifies fixed ID (identifier) information on the board, but it has the following drawbacks.

(1) The maximum value that can be used to identify a board is determined by the bit width of the ID information, and even if identification exceeding that value is required, it will not be possible. Therefore, it is necessary to have some margin in the bit width, which makes it expensive.

(2) If there are boards that do not have the function to output the above ID information, it will not be possible to identify them.

[Purpose of the invention]

The present invention is based on the above-mentioned idea, and can easily handle cases where the number of boards to be identified increases in board identification, or where there are boards for which no identification function has been taken into account at all, and which is inexpensive. The purpose is to provide an automatic identification method.

[Means to achieve the purpose]

Therefore, the automatic board identification method of the present invention is applicable to a computer system having a central processing unit and a board removably connected to a bus connected to the central processing unit via a connector and having an identifier portion. This is an automatic board identification method, and the identifier section sets the identifier information to an initial value when the central processing unit issues an initialization command specifying the board, when the power is turned on, or when the system is reset. and when the central processing unit issues an identifier read command specifying the board, outputs the stored identifier information onto the data bus, and then updates and stores the identifier information. That is.

[Embodiments of the invention]

FIG. 1 is a diagram showing an example of a computer system to which the present invention is applied. In Figure 1, 1 is a central processing unit, 2-0 and 2-1 are substrates, 3-0 and 3-
1 is a connector on the receiving side, and 4-0 and 4-1 are connectors on the board, respectively. Connectors 3-0 and 3-1 on the receiving side are connected to the bus, and the connectors of the board are inserted into these. The receiving connector 3-0 is called the slot 0 connector, and the receiving connector 3-1 is called the slot 1 connector. An identifier portion, which will be described later, is provided in the substrates 2-0 and 2-1. Devices such as printers and modems are connected below the board. Although there are only two substrates in FIG. 1, in reality, a large number of substrates are installed.

In the present invention, a circuit board with a predetermined bit width formed by F/F (flip-flop), etc.
An identifier section is provided that has an ID output function, an ID initial value setting function, and a function to update the ID output value every time the program reads the ID. Examples of the identifier part are shown in Figs. 2 and 4, and simple designs include one in which specific bits are sequentially inverted and other bits held at the same value, or one in which multiple bits are used as a counter. There are things that need to be updated, etc., and as the number of identification items increases, it is only necessary to adopt a cheaper implementation method. FIG. 2 shows one embodiment of the configuration of the identifier section. In Figure 2, 5 is a flip
Flops 6-0 through 6-3 represent three-state gates, respectively. A unique address is assigned to the identifier part. Note that the identifier portions of boards inserted into the same slot have the same address. When the central processing unit wants to set the status of the identifier part of a certain board to the initial value,
Specify the address assigned to that identifier part
Issue an ID initialize command (write command). Then, a clear signal is applied to the clear terminal of flip-flop 5. It is also possible to apply a clear signal unconditionally at power-on or system reset. When the central processing unit issues an ID read command (read command) specifying the address assigned to the identifier section,
A pulse is applied to the clock terminal of flip-flop 5 and the control terminals of three-state gates 6-0 to 6-3, and the identifier information corresponding to the state of flip-flop 5 is transferred to the bit line of the data bus.
It is output to DB0 to DB3, and then the state of flip-flop 5 is inverted. FIG. 3 shows the relationship between the number of ID read commands issued and ID information in the identifier section of FIG.
When the second ID read command is issued, "0100"
ID information is output on the data bus, and when the second ID read command is issued, ID information of "1010" is output on the data bus, and the third ID
When a read command is issued, ID information of "0100" is output onto the data bus. The following is as shown.

FIG. 4 is a diagram showing another embodiment of the identifier section. In FIG. 4, 7 represents a counter, and 8-0 to 8-3 represent three-state gates. When the central processing unit wants to set the state of the identifier section of a certain board to an initial value, it issues an ID initialize command (write command) by specifying the address assigned to the identifier section. Then, a clear signal is applied to the clear terminal of the counter 7.
When the central processing unit specifies the address assigned to the identifier section and issues an ID read command (read command), a pulse is generated at the clock terminal of the counter 7 and the control terminals of the three-state gates 8-0 to 8-3. The identifier information corresponding to the state of the counter 7 is output to the bit lines DB0 to DB3 of the data bus, and then the count value of the counter 7 is incremented by one. FIG. 5 shows the relationship between the number of ID read commands issued and the ID information in the identifier section of FIG. 4. When the first ID read command is issued, the ID information of "0000" becomes the data. When the second ID read command is issued, the ID information of "1000" is output onto the data bus, and when the third ID read command is issued, the ID information of "0010" is output. Information is output onto the data bus. The following is as shown in the figure.

The central processing unit program reads the ID information a predetermined number of times and stores it in memory,
Identify the type of board by searching a board identification table. FIG. 6 shows an example of the configuration of a board identification table held by the central processing unit,
IDT indicates the board identification table. For example, the ID information string for board #1 is X ₁₁ , X ₁₂ , . . . , X _1o . Further, only when there are boards that do not have an ID output function for identification, if the read ID information string is not defined on the board identification table IDT, the board does not have the ID output function. It can also be identified. Generally, if the bit width of one piece of ID information is N and the number of times a program is read is n, it is possible to identify up to ( ^2N ) ⁿ =2N ⁺ⁿ types of boards.

FIG. 7 is a diagram for explaining the identification process.
When the central processing unit wants to know the type of board inserted into a certain slot, it specifies the address of the identifier section of the board, issues an ID read command a predetermined number of times, and stores the read ID information in memory. Store. After reading, the read ID information string is compared with the contents of the board identification table IDT to recognize the type of board.

〔Effect of the invention〕

As is clear from the above description, the following effects can be obtained according to the present invention.

(a) Conventionally, an identifier section with a width of (N+n) bits is required to identify 2 ^N+n ways, but since it only needs a width of X bits, it can be realized with cheaper hardware.

(b) By increasing the number of times the program is read (=n), the number of distinguishable boards increases, so even if the number of types of boards increases, it can be easily handled.

(c) Since the ID information read by the central processing unit program is updated regularly, by increasing the number of readings, even if there are boards without any ID output function, they can be identified. You can.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a computer system to which the present invention is applied, FIG. 2 is a diagram showing an embodiment of the configuration of an identifier section, and FIG. 3 is a diagram showing an example configuration of an identifier section in FIG.
A diagram showing the relationship between the number of ID read commands issued and ID information, FIG. 4 is a diagram showing another embodiment of the identifier section, and FIG. 5 is a diagram showing the number of ID read commands issued and ID information in the identifier section of FIG. 4. FIG. 6 is a diagram showing a configuration example of a substrate identification table held by the central processing unit, and FIG. 7 is a diagram for explaining the identification process. 1... Central processing unit, 2-0 and 2-1... Board, 3
-0 and 3-1...receiving side connector, 4-0 and 4-
1... Board connector, 5... Flip-flop,
6-0 or 6-3...3 state gate, 7...
Counter, 8-0 or 8-3...3-state gate, IDT...board identification table.

Claims (1)

[Claims] 1. An automatic board identification method in a computer system having a central processing unit and a board removably connected to a bus connected to the central processing unit via a connector and having an identifier section, the board being sets the identifier information to an initial value and stores it when the central processing unit issues an initialization command specifying the board, turns on the power, or resets the system, and the central processing unit An automatic board identification method characterized in that when a specified identifier read command is issued, stored identifier information is output onto a data bus, and then the identifier information is updated and stored.