JPH0836543A - Method and device for detecting slave board - Google Patents

Abstract

PURPOSE:To detect whether or not a substrate is present, without adding a signal line by using a general purpose bus system and to start up the device normally as a device without the substrate. CONSTITUTION:A VME bus 12 consists of a VME address bus, a VME data bus, and a VME control bus, and is connected to plural slave modules as substrates mounted in the device. The master module 11 is a substrate which is connected to the VME bus 12 and controls the whole device. A VME bus buffer 13 is provided in the master module 11 and sends and receives signals to and from the VME bus. A timer 1 for detection is actuated by the CPU 17 of the master module 11 to detect a.slave module through an internal bus 21. A bus access part 15 for detection accesses the slave module 11 to detect the presence of the slave module 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slave board detection method and apparatus, and more particularly to a VME (Versa).
Module Europe: Versa Module Europe) A method for detecting a slave board (board) of a general-purpose bus system that configures a device using a plurality of substrates such as a bus system, and the device.

[0002]

2. Description of the Related Art In industrial devices such as communication devices and control devices, a method of constructing the device using a plurality of substrates having a certain function is often used. This is because if the function of the device is to be realized by a single board, the board becomes too large and the processing becomes complicated.
This is to facilitate maintenance and version upgrade of the device itself. Such an idea is general, and therefore standards for constructing devices, such as the VMEbus standard, are standardized. In addition, components and boards conforming to such standards are also commercially available, and can be easily and inexpensively obtained.

In a communication device using a VME bus, the device is composed of a master module, which is a substrate for managing the entire device, and a plurality of slave modules, which are substrates for realizing the respective functions. The configuration of the device is managed by the master module, and thus the function and configuration of the entire device are grasped by the master module.

FIG. 6 is a block diagram of a center device for performing communication processing using the VME bus. In the figure, 31 is a communication processing device, 32 is a master module of the communication processing device, and 33 is a slave module for performing line control. , 33a is mounted, 33b is not mounted, 34 is a slave module for processing data, 34a is mounted, 34b is not mounted, 35 is between modules in the device , A system bus for exchanging commands and data, 36 is a signal line for connecting to a line,
A local bus 37 connects the slave modules 34 that perform data processing.

In the device 31, a maximum of four slave modules 33 for line control and a maximum of four slave modules 34 for data processing can be mounted. The number of slave modules 34 for line control is determined by the number of terminals that can be simultaneously connected by the center device. The number of slave modules 34 that perform data processing is determined by the content of services and processing performed by the center device. In this configuration example, the device 31 is a slave module 33 that performs line control.
2 a, slave module 34a for data processing
3 are mounted.

The module mounted inside the device 31 is
All are connected via a VME bus 35 which is a system bus. In addition, the slave module 33a that controls the line
Are connected to the lines from the respective modules via signal lines 36a. The data sent from the line via the line control 34a is sent to the slave module 34a which processes data according to the instruction of the master module 32 via the VME bus 35.

Slave module 34 for processing data
After performing data processing, a transmits to the slave module 33a of line control via the VME bus 35 according to the instruction of the master module 32. The line control slave module 33a sends data to the line via the signal line 36a. Slave module 34a for data processing
Are connected by a local bus 37a different from the VME bus 35 and distribute the processing contents according to the contents of data processing.

FIG. 7 is a diagram showing an address map of the device 31 shown in FIG. Although the address map is device-specific, the range of addresses that can be used in the VME bus is from x00000000h to xFFFFFFFFh, depending on the number of signals on the address bus. Addresses are assigned to each board during this period, but in order to unify the logical interfaces of the master module and slave modules, the slave module type is identified by the upper digit of the address and multiple identical modules are identified by the middle digit. In general, the communication registers of the master module and the slave module are set in the lower digits of the address by performing identification between them.

In FIG. 7, from x1000000h to the slave module 33, x20000000
Addresses are assigned to the slave module 34 from h. In addition, for a plurality of slave modules 33, x1000000h to x01000000
x 2000 for each slave module 34
Addresses are allocated from 000h to x01000000h to identify the same module.

In the device 31, the slave modules 33, 3
It is possible to mount 4 modules at maximum, but only 2 modules are mounted on the slave module 33 and only 3 modules are mounted on the slave module 34. Therefore, although only four modules are allocated as addresses, the addresses where the modules are actually mounted are shown in FIG.
become that way.

When a function is added or changed in such a device, the number of slave modules is changed or slave modules having different functions are added. At this time, the configuration of the entire apparatus naturally changes, so it is necessary to notify the master module that the configuration of the apparatus has changed by some method. As a method of notifying the master module of the configuration change, there is a method of changing the software of the master module. This is to change the information on the device configuration of software operating on the master module by replacing a ROM (Read Only Memory) or rewriting a program loaded by the master module.

There is also a method in which a switch for setting the configuration of the entire apparatus is provided and the master module reads the setting contents of the switch to notify the configuration of the entire apparatus. Alternatively, there is also a method in which the master module and each slave module are connected by a signal line and the installed slave module is detected by the master module.

[0013]

In the conventional slave board detection method, when the configuration of the device is changed, the master module board for managing the operation of the entire device is mounted on the slave module board mounted on the device. If it is not known in advance, when a board that is not mounted is accessed, a hardware response (acknowledge) does not come back, so a bus error is determined and the device malfunctions. In order to avoid this, the software of the master module is changed, but the work itself is complicated to replace the program ROM, and there are secondary problems such as damage to the hardware due to the work. Can occur.

Although a large device has a function of loading a program, not all devices using the VME bus have the function of loading a program. An external storage device such as a hard disk drive is required, which increases the cost of the device. The method of setting the slave module by switch setting or the like is not a problem in a dedicated device, but the hardware for reading the switch and the setting is required for the number of slave modules, and is not versatile. In the method of providing a signal line for detecting a substrate, it is difficult and not general to add a signal line in a general-purpose bus system.

As described above, in a general-purpose bus system such as a VME bus system that uses a plurality of boards to configure a device, the number of boards to be mounted can be changed, or a board having a certain function can be added or deleted. May be configured and operated. The board that manages the operation of the entire device (master board) when the device configuration is changed must know the configuration of the substrate (slave board) mounted on the device in advance to access the unmounted substrate. In this case, since a hardware-like response (acknowledge) is not returned, it is determined that a bus error has occurred and the device malfunctions. Therefore, in a general-purpose bus system, it is expected to detect the presence or absence of a board by a simple hardware method.

The present invention has been made in view of the above circumstances, and it is possible to detect the presence or absence of a substrate by using a general-purpose bus system without adding a signal line. An object of the present invention is to provide a slave board detection method and a device thereof that can be normally started up as a device without a substrate.

[0017]

In order to solve the above-mentioned problems, the present invention detects (1) a bus access time-out among controls for exchanging data between boards via a bus. A bus control circuit provided on a substrate having a function is provided with a timer means for detecting a board and a bus access means, and (2) by using the bus access means at the first bus access,
If the timer means is started and there is no response before the timer expires, it is determined that there is no board at the access destination, or (3) connection with a plurality of slave modules that are boards mounted inside the device. A VME bus, a master module that is a board connected to the VME bus and that manages the entire apparatus, and a VME bus provided on the master module.
A VMEbus buffer for exchanging signals with the ME bus, a detection timer activated by a central processing unit of the master module for performing a detection operation of a slave module via an internal bus, and the slave module And a detection bus access unit for detecting the presence of the slave module, and the presence or absence of board mounting is detected.

[0018]

By detecting the slave board by the method described above, it is possible to detect the slave board without adding a signal line for detecting the presence or absence of the board or special hardware. Furthermore, even if the configuration of the entire device is changed, it is not necessary to change the program of the master module, and the device can operate normally.

[0019]

Embodiments will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining a slave board detection method according to the present invention. In the figure, 11 is a master module, 12 is a general-purpose VME bus, and 13 is a signal exchange between the VME bus and the master module. VME bus buffer, 14 is a slave module detection timer,
15 is a bus access unit for detecting a slave module, 16
Is a VM for the master module to control the VMEbus
E-bus controller, 17 is the CPU of the master module
(Central processing unit), 18 is a program ROM for controlling the master module and the entire device, 19 is a data RAM (Random A) for controlling the master module and the entire device
ccess Memory), 20 is a timer for controlling the master module and the entire apparatus, and 21 is an internal bus.

The VME bus 12 is composed of a VME address bus, a VME data bus, and a VME control bus, and is connected to a plurality of slave modules which are boards mounted inside the apparatus. The master module 11 is a board that is connected to the VME bus 12 and manages the entire apparatus.
The VME bus buffer 13 includes the master module 11
For exchanging signals with the VME bus. The detection timer 14 uses the internal bus 21.
In order to perform the detection operation of the slave module via
It is activated by the CPU 17 of the master module 11. The detection bus access unit 15 accesses the slave module 11 and detects the presence of the slave module 11. In this way, the presence / absence of board mounting can be detected, and the apparatus can be normally started up even without the board.

FIG. 2 is a flow chart when detecting a slave module using the configuration of the present invention. In addition,
N is the number of slave modules that can be mounted in the device.
3 (a) to (d) to 5 (a) to (d) are timing charts on the VME bus and the internal bus using the present invention. FIGS. 3A to 3D are timing charts when the slave module is accessed and there is a slave module, and FIGS. 4A to 3D are timing charts when the slave module is accessed and there is no slave module, 5A to 5D are timing charts of bus errors when the slave module detection operation is terminated and the VME bus is normally accessed.

Hereinafter, the steps (S) will be sequentially described with reference to FIG. First, the power of the entire apparatus is first turned on (S1), and the CPU 17 of the master module initializes the inside of the master module via the internal bus 21 (S2). When the initialization is completed, the slave module detection operation is started for all the slave modules according to the program in the ROM 18 (S3). At this time, the CPU 17 first activates the detection timer 14 via the internal bus 21, and then accesses the slave module via the detection bus access unit 15 and the VME bus controller 16 (S4).

If a slave module is present,
As shown in the timing charts of FIGS. 3A to 3D, the master module is a DS of the VME bus (see FIG.
After asserting (a)), V
The master module recognizes that there is a slave board (S6) since there is a response by DTACK (FIG. 3B) of the ME bus (S5). After that, the detection timer is cleared by the internal internal bus 21 (FIG. 3 (d)). The master module performs this operation for all slave modules N that can be mounted on the device.

When the slave module is not mounted, as shown in the timing charts of FIGS. 4 (a) to 4 (d), the VME bus from the slave module is compared with the DS of the VME bus (FIG. 4 (a)). DTACK (Fig. 4
There is no response of (b)) (S5). At this time, the detection timer expires (S7), and the master module uses the internal bus 2
1 clears the detection timer (Fig. 4 (d)), and VME
Negate the DS of the bus. Then, the master module recognizes that there is no slave substrate (S8), and performs the next detection operation.

The above operation is performed N times as the maximum number of slaves mounted, and it is detected whether or not each slave module is mounted (S9). When the mounted slave module is confirmed, the master module performs the initialization operation only for the mounted slave module (S10). At this time, like the normal VME access, the bus error timer is activated as shown in the timing charts of FIGS.

As is clear from the timing chart,
The expiry time T2 of the detection timer needs to be set longer than the response time T1 when the board is present and shorter than the bus error timeout time T3 of the normal bus access. T1 is several hundreds of nsec because of the hardware response of the slave module, T3 is several hundreds of μsec because of the software timer of the master module, and T2 may be set during this period, and detection is easily possible.

As described above, in addition to the hardware-based timer for detecting a bus error, the apparatus is started up by providing the timer means for board check and the bus access means, which are shorter in time than the bus error timer. When accessing the board, the apparatus can be operated without causing a bus error even if the board not mounted is accessed, and the presence / absence of board mounting can be detected.

[0028]

As is apparent from the above description, according to the present invention, the master module can know the mounting state of the slave module inside the device without adding any special function or hardware. Further, it becomes possible for the master module to know the mounting state inside the device.
Further, even if the mounting state inside the device is changed, the device can operate normally without changing the program or setting the conditions. Therefore, by using the present invention, it is possible to provide an inexpensive and highly reliable general-purpose device.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a slave board detection method according to the present invention.

FIG. 2 is a flowchart illustrating an embodiment of a slave board detection method according to the present invention.

FIG. 3 is an operation timing chart of the present invention (with a slave module).

FIG. 4 is an operation timing chart of the present invention (without a slave module).

FIG. 5 is an operation timing chart of the present invention (normal VM
E access).

FIG. 6 is a configuration diagram for explaining a conventional slave board detection device.

FIG. 7 is a diagram showing an address map of a conventional slave board detection device.

[Explanation of symbols]

11 ... Master module, 12 ... General-purpose VME bus, 1
3 ... VME bus buffer, 14 ... Slave module detection timer, 15 ... Slave module detection bus access part, 16 ... VME bus controller, 17 ... Master module CPU, 18 ... Program ROM, 19 ...
Data RAM, 20 ... Timer, 21 ... Internal bus.

Claims (3)

[Claims] 1. A board detection timer in a bus control circuit provided on a board having a function of detecting a time-out of bus access, among controls for exchanging data between boards via a bus. A slave board detection method comprising: means and bus access means. 2. When the first bus access is made, the bus access means is used to activate the timer means, and if there is no response before the timer expires, it is determined that there is no board at the access destination. The slave board detection method according to claim 1. 3. A VME bus connected to a plurality of slave modules, which are boards mounted inside the device, and the VM.
A master module, which is a board connected to the E bus and managing the entire apparatus, a VME bus buffer provided in the master module for exchanging signals with the VME bus, and a slave module via an internal bus. A detection timer activated by the central processing unit of the master module and a detection bus access unit for accessing the slave module and detecting the presence of the slave module. A slave board detection device characterized in that the presence or absence of mounting is detected.