JP2006338232A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system allowing a slave device to recognize other slave devices with a simple construction and allowing the slave devices to communicate directly not via a host device in the communication system where the host device and a plurality of slave devices are connected with an input output bus such as a PCI bus. <P>SOLUTION: In the communication system 1, the host device and the plurality of slave devices by the input output bus, such as the PCI bus, are connected. The host device is provided with a means for detecting a first slave device connected to the input output bus and a means for acquiring device information necessary for accessing the detected first slave device to notify a second slave device that it has acquired the information. The second slave device is provided with: an acquisition means for acquiring device information from the host device when it is notified; and a communication preparation means for accessing the first slave device on the basis of the acquired device information to prepare for communication between itself and the first slave device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication system in which a host device and a plurality of slave devices are connected by an input / output bus.

  In a communication system in which a host device and a slave device are connected by a PCI (Peripheral Component Interconnect) bus, a configuration register (Configuration) for setting the characteristics, type, operation method, etc. of the device (slave device) connected to the PCI bus Register) is provided in each slave device (see, for example, Patent Document 1).

In the communication system as described above, when the host device recognizes the slave device at the time of system startup, the host device accesses the configuration register of the slave device and sets the operating environment such as writing the base address and reading the device ID. . Then, the host device communicates with the slave device based on the setting.
Japanese Patent Laid-Open No. 11-282791

  However, in a communication system in which a host device and a plurality of slave devices are connected by an input / output bus such as a PCI bus, the PCI standard is basically defined for communication between the host device and the slave device. Only the host device recognizes the slave device as described above. For this reason, there is a problem that the slave device cannot recognize other slave devices and the slave devices cannot communicate directly with each other without going through the host device.

  The present invention has been made in view of such a problem. In a communication system in which a host device and a plurality of slave devices are connected by an input / output bus such as a PCI bus, the slave device can be configured in a simple configuration. An object of the present invention is to provide a communication system that can recognize slave devices and directly communicate with each other without using a host device.

  To achieve the above object, the communication system according to claim 1 is a communication system in which a host device and a plurality of slave devices are connected by an input / output bus, and the host device is connected to the input / output bus. Means for detecting the first slave device, means for acquiring device information necessary for accessing the detected first slave device from the first slave device, and notifying the second slave device to that effect; The second slave device, when receiving the notification, obtains the device information from the host device, and accesses the first slave device based on the obtained device information, Communication preparation means for preparing for communication with one slave device. .

  The communication system according to claim 2 is the communication system according to claim 1, wherein the host device includes a memory that stores the device information acquired from the first slave device. The acquisition unit is configured to acquire the device information from the host device by reading the device information from the memory when receiving the notification.

  The communication system according to claim 3 is the communication system according to claim 1 or 2, wherein the first slave device has an area for writing information to another device connected to the first device. The communication preparation means of the second slave device writes information necessary for communication in an area dedicated to the second slave device provided in the memory of the first slave device. In this case, the communication preparation is performed.

  A communication system according to a fourth aspect is the communication system according to any one of the first to third aspects, wherein the input / output bus is a PCI bus.

  According to the communication system according to claim 1 and 4, the second slave device acquires device information acquired by the host device, accesses the first slave device, and prepares communication with the first slave device. Do. Therefore, the second slave device can directly communicate with the first slave device after the communication preparation is completed. Accordingly, the slave device can easily recognize other slave devices by a simple configuration in which the host device acquires the device information acquired from the first slave device from the host device, and the slave device can be recognized without going through the host device. They can communicate directly with each other.

  According to the communication system according to claim 2 and 4, when the second slave device receives the notification, the second slave device accesses the first slave device by performing a process of reading the device information from the memory of the host device. Therefore, it is possible to easily obtain necessary information.

  According to the communication system according to claim 3 and 4, the second slave device writes the information necessary for communication in the area dedicated to the device provided in the first slave device that is the communication partner. By making two slave devices perform each other, communication preparation can be easily performed without performing a complicated sequence.

  Hereinafter, a case where the communication system according to the embodiment of the present invention is applied to a multifunction machine having a color copy function, a facsimile communication function, a network scanner function, a network printer function, and the like will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a communication system (computer system) 1 according to the present embodiment. In this communication system 1, a host device and a plurality of slave devices are connected by a PCI bus (input / output bus) 2. In this embodiment, an MFP controller 3 that is a host device and a slave device are used. A certain color image processing board 4, printer controller 5, and network board 6 are connected by the PCI bus 2.

  This PCI bus (Peripheral Component Interconnect Bus) 2 is a 32-bit bus whose standard is established by PCI SIG (PCI Special Interest Group), and the PCI bus 2a (2) and the PCI bus constituting the PCI bus 2 2b (2) is connected by a PCI bridge 7 which is a circuit for interconnecting two PCI buses.

  The MFP controller (host device) 3 functions as a host device of the communication system 1. Specifically, a color space for color image data output from a scanner (document reading unit) 9 that reads color image data (for example, RGB color system color image data) composed of a plurality of color components from a document. Performs image processing such as conversion and compression (encoding), transfers (transmits) the image data to the color image processing board 4 or the network board 6 via the PCI bus 2, and processes an original with an external device (not shown). Processing for transmitting and receiving color image data by facsimile is performed.

  The MFP controller 3 includes a control unit (CPU: Central Processing Unit) 10, a PCI host controller 11, an interrupt control register 12, and a RAM (Random Access Memory) 13. These units 10 to 13 are connected by a host system bus 14. It is connected so that it can communicate.

  The control unit 10 controls each unit constituting the MFP controller 3. The PCI host controller 11 controls communication performed via the PCI bus 2 with a slave device (color image processing board 4, printer controller 5, or network board 6). The interrupt control register 12 is a memory for writing an interrupt request when each device constituting the communication system 1 generates an interrupt to another device.

  The interrupt control register 12 is connected to the control unit 10 of the own device 3 by the interrupt signal line 16, and is also connected to the control unit 25 of each slave device 4 to 6 by the interrupt signal lines 17 to 19, and the interrupt request register When an interrupt request is written in the interrupt control register 12 by the original (command transmission side) device, an interrupt signal is output to the interrupt request destination (command reception side) device.

  A RAM (memory) 13 functions as a main memory, a work area, and the like of the control unit 10 and stores various setting information. As shown in FIG. 2, the RAM 13 is provided with a sub-configuration area 21, a command area 22, and a unit management area 23.

  The command area 22 is an area for the slave devices 4 to 6 connected to the self device 3 via the PCI bus 2 to write commands, responses, data having a small data size, etc. to the self device 3. Communication with the slave devices 4 to 6 is performed using the area 22. The subconfiguration area 21 is an area in which the size of the command area 22, the address of the command area 22, the interrupt factor from the slave devices 4 to 6 and the like are written. The unit management area 23 is an area where device information necessary for accessing the slave device is written.

  In addition to the above-described units 10 to 13, the MFP controller 3 is not shown, but stores a program for controlling each unit of the MFP controller 3 by the control unit 10, and the RGB table output from the scanner 9. For example, a color space conversion circuit that converts color image data into, for example, YCrCb color image data, a codec that compresses or expands image data, an image memory that stores image data, and facsimile communication with an external device. A communication unit including a modem and an NCU (Network Control Unit) is provided.

  The color image processing board 4 functions as a slave device of the communication system 1 and performs image processing necessary for printing out image data transferred from the MFP controller 3 on paper. Specifically, color space conversion for converting color image data of the YCrCb color system output from the MFP controller 3 into, for example, CMYK color data, or binarization (or quaternary) of the color data subjected to color space conversion. Gradation reduction processing or the like.

  The color image processing board 4 includes a control unit (CPU) 25a (25), a PCI controller 26a (26), a RAM (memory) 27a (27), and the like. These units 25a to 27a are connected by a local bus 28. It is connected so that it can communicate.

  The control unit 25a controls each unit constituting the device 4 itself. The control unit 25a is equipped with an interrupt controller (not shown) and causes the control unit 25a to generate an interrupt when receiving an interrupt signal from the interrupt control register 12 via the interrupt signal line 17. Can do. The PCI controller 26a controls communication performed via the PCI bus 2 with other devices (here, the MFP controller 3, the printer controller 5, or the network board 6). The PCI controller 26a incorporates a so-called configuration register which is a register for setting device characteristics, types, operation methods, and the like, and is configured (initialized) by the PCI host controller 11. It has come to be. Only the PCI host controller 11 of the host device 3 can access the configuration register.

  The RAM 27a functions as a main memory, work area, and the like of the control unit 25a, and stores various setting information. Although not shown, the RAM 27a is provided with a sub-configuration area and a command area, like the RAM 13 of the MFP controller 3. The configuration area and the command area will be described in detail later by taking as an example one provided in the memory (RAM 27b) of the printer controller 5.

  In addition to the above 25a to 27a, this color image processing board 4 is not shown, but a ROM for storing programs for controlling each part of the color image processing board 4 by the control unit 25a, YCrCb color system Are provided with a color space conversion circuit for converting the color image data into CMYK color data, a gradation reduction processing circuit for binarizing or quaternizing the color data subjected to color space conversion by error diffusion processing, and the like.

  The printer controller 5 functions as a slave device of the communication system 1, and based on the image data (color data) transferred from the color image processing board 4 and the image data transferred from the network board 6, the printer 30. To control.

  The printer controller 5 includes a control unit (CPU) 25b (25), a PCI controller 26b (26), and a RAM (memory) 27b (27). These units 25b to 27b can communicate with each other via a local bus 31. It is connected. The control unit 25b, the PCI controller 26b, and the RAM 27b have the same configurations and functions as the control unit 25a, the PCI controller 26a, and the RAM 27a of the color image processing board 4, respectively.

  In addition to the above 25b to 27b, the printer controller 5 includes a ROM that stores a program for controlling each unit of the printer controller 5 by the control unit 25b, and a video ASIC (Application Specific Integrated Circuit) that controls the printer 30. ) And the like, and the printer 30 is controlled based on the color image data transferred from the color image processing board 4 via the PCI bus 2 and the color image data transferred from the network board 6 to perform the printing process. Execute.

  On the other hand, the printer 30 records an image of image data on a sheet, and can record both color image data and monochrome image data on a sheet. As a recording method in the printer 30, for example, various recording methods such as an electrophotographic method and an ink jet method can be used.

  The network board 6 functions as a slave device of the communication system 1, and the color image data transferred from the MFP controller 3 via the PCI bus 2 is converted into monochrome image data as it is or as a client on the LAN 32. Processing for transferring to the PC 33, processing for transferring the image data output from the client PC 33 to the MFP controller 3 via the PCI bus 2 for facsimile transmission, and printing out the image data output from the client PC 33 A process of transferring to the printer controller 5 via the PCI bus 2 is performed.

  The network board 6 includes a control unit (CPU) 25c (25), a PCI controller 26c (26), a RAM (memory) 27c (27), and the like. These units 25c to 27c can communicate with each other via a local bus 34. It is connected to the. The control unit 25c, the PCI controller 26c, and the RAM 27c have the same functions and configurations as the control unit 25a, the PCI controller 26a, and the RAM 27a of the color image processing board 4, respectively.

  The controller 25c is equipped with a LAN controller 35 for communicating with the client PC 33 on the LAN 32, and can transmit and receive various data to and from the client PC 33 on the LAN 32 as described above. is there. In addition to the above 25c to 27c, the network board 6 includes a ROM that stores a program for controlling each part of the network board 6 by the control unit 25c, and a color monochrome that converts color image data into monochrome image data. A conversion circuit, a binarization circuit that binarizes multi-valued monochrome image data, a codec that compresses the binarized monochrome image data by the MH, MR, MMR, JBIG method, and the like are provided.

  FIG. 3 is a diagram schematically showing the configuration of the RAM 27 b of the printer controller 5. The RAM 27b is provided with a sub-configuration area 37 and a command area 38. First, the command area 38 will be described below. In this command area 38, the other device 3, 4 or 6 connected to the own device 5 via the PCI bus 2 is a command or response to the own device 5, data having a small data size (for example, data of less than 104 bytes). ) Etc., and the printer controller 5 is logically divided into a plurality of areas for each device that can communicate via the PCI bus 2. In this embodiment, the command area 38 is logically divided into an MFP controller command area 39, a color image processing board command area 40, a network board command area 41, and an additional device command area 42. It is divided.

  Here, the MFP controller command area 39 is an area where the PCI host controller 11 of the MFP controller 3 writes commands, responses, and the like to the printer controller 5 via the PCI bus 2 based on the control command of the control unit 10. The color image processing board command area 40 is an area in which the PCI controller 26a of the color image processing board 4 writes commands, responses, and the like for the printer controller 5 via the PCI bus 2 based on the control command of the control unit 25a. The network board command area 41 is an area where the PCI controller 26c of the network board 6 writes commands, responses, and the like for the printer controller 5 via the PCI bus 2 based on the control command of the control unit 25c. In the additional device command area 42, when a new slave device is added to the communication system 1, the PCI controller of the added slave device writes a command, a response, and the like for the printer controller 5 via the PCI bus 2. This is an area that is provided in advance to cope with the addition (addition) of slave devices.

  As described above, the area (area) in which other devices 3, 4 or 6 connected to the self device 5 via the PCI bus 2 write various data such as commands and responses are stored in the RAM 27b of the printer controller 5. 39 to 41 are provided for each of the other devices.

  The command areas 39 to 42 for each device are further logically divided into a header area and a data area. The header area and the data area are referred to as a color image processing board command area 40 here. An example will be described. The header area 43 of the color image processing board command area 40 includes a header type, a command mailbox ID, a response mailbox ID, a command number (command), a data address (start address), a data count (data size), and the like. In the data area 44, data having a small data size, responses, and the like are written by another device connected to the device 5 (in this area, the color image processing board 4).

  The header type is memory information indicating the usage status of the command area 40 for the color image processing board by the device (color image processing board 4) on the command transmission side, and indicates that the command area 40 for the color image processing board is not used. Information indicating that the color image processing board command area 40 is being used by a command to the printer controller 5, or indicating that the color image processing board command area 40 is being used by a response to the printer controller 5. Any of the information. The control unit 25b of the printer controller 5 accesses the RAM 27b via the local bus 31 and obtains the header type of the header area 43, thereby using the color image processing board command area 40 by the color image processing board 4. Can be judged.

  The command mailbox ID is a mailbox ID when the device on the command issuing (sending) side (here, the color image processing board 4) waits for a response, and when not waiting for a response, “0” is set as the command mailbox ID. Is set. The response mailbox ID is a mailbox ID when the side that issued the response (color image processing board 4) waits for a command. When the command does not wait for a command, “0” is set as the response mailbox ID.

  Here, the command number (command) is a scalar value indicating a process requested by the color image processing board 4 to the printer controller 5, and the control unit 25 b of the printer controller 5 is written in the header area 43. By acquiring the command number, it is possible to determine what processing the device 5 should execute.

  The data address (hereinafter referred to as “head address”) is an address on the PCI space, and when data is transferred from one device to the other device, the head of the location where the data to be transferred is stored is stored. Or an address indicating the beginning of a location where data after transfer is to be written. For example, when data is transferred from the color image processing board 4 to the printer controller 5, the address indicating the head of the location where the data to be transferred is stored in the RAM 27a, or the transferred data should be written in the RAM 27b. This is the address that indicates the beginning of the place.

  The data count (data size) indicates the data size of data to be transferred when data is transferred using an area other than the command area 38. Therefore, for example, when data is transferred from the color image processing board 4 to the printer controller 5, the control unit 25 b of the printer controller 5 transfers the data to its own device 5 based on the head address and data count of the header area 43. It is possible to specify the position on the RAM 27a of the color image processing board 4 where the power data is stored.

  Specifically, the data written in the data area 44 is data having a small data size (for example, data having a data size of less than 104 bytes) written by the PCI controller 26a of the color image processing board 4 via the PCI bus 2. ), The response of the color image processing board 4 to the printer controller 5, and the like. Note that data having a large data size exceeding the capacity of the data area 44 is written in an area other than the command area 38 in the RAM 27b.

  The MFP controller command area 39 is different from the PCI host controller 11 of the MFP controller 3, and the network board command area 41 is different from the PCI controller 26 c of the network board 6 except for devices for writing data. Thus, the same information as in the color image processing board command area 40 is written.

  Furthermore, the devices 3, 4, and 6 are also provided with command areas for other devices connected to the own device via the PCI bus 2 to write commands and responses. The command areas of the devices 3, 4, and 6 are configured in the same manner as the command area 38 described with reference to FIG. 3 except that the combination of devices that are connected to the device and write to the command area is different. Therefore, the detailed description is abbreviate | omitted.

  FIG. 4 is a diagram schematically showing a sub-configuration area 37 provided in the RAM 27b of the printer controller 5. As shown in the figure, the sub-configuration area 37 includes a device information area 46, an MFP controller area 47, a color image processing board area 48, a network board area 49, and an additional device area 50. Divided.

  The device information area 46 is an area for storing information on a device (printer controller 5) including the RAM 27b provided with the sub-configuration area 37, and includes a device ID, a unit number, a status, and a command area. Information such as the size, command area 0 offset, and unit management address is written.

  The device ID is an identifier of a device having the sub-configuration area 37, and here is information indicating the printer controller 5. The unit number is information indicating which command unit is used by the device (here, the printer controller 5).

  The status is information indicating whether or not the initialization process for the configuration register built in the PCI controller 26b is completed. When the PCI host controller 11 performs configuration (initialization processing) of the configuration register built in the PCI controller 26b in the configuration cycle and completes the setting of the operating environment of the PCI controller 26b, the information indicating that fact is displayed in the status. Is written in the device information area 46. After receiving the writing of this information, the printer controller 5 can access the unit management area 23 provided in the RAM 13 of the MFP controller 3 by the PCI controller 26b.

  The command area size is information indicating the size (capacity) of the command area 38. The command area 0 offset is information indicating the start address of the command area 38 by the offset from the start address of the subconfiguration area 37. When other devices (the color image processing board 4 and the network board 6) can access the sub-configuration area 37, the printer controller reads the command area size and command area 0 offset information from the device information area 46. The position information of the command area 38, which is information necessary for communication with the terminal 5, can be acquired. Thereby, the location (PCI memory space address) of the command area 38 in the RAM 27b can be specified.

  The unit management address is an address on the PCI space of the unit management area 23 provided in the RAM 13 of the MFP controller 3 which is a host device. This unit management address is written by the PCI host controller 11 which has finished the configuration for the configuration register of the PCI controller 26b.

  The MFP controller area 47 is an area for writing information necessary for the MFP controller 3 to communicate with the printer controller 5 and an interrupt factor when generating an interrupt to the printer controller 5. is there. The color image processing board area 48 is an area where the color image processing board 4 writes information necessary for communication with the printer controller 5 and an interrupt factor when the printer controller 5 generates an interrupt. This is a dedicated area for the board 4. The network board area 49 is an area for writing information necessary for the network board 6 to communicate with the printer controller 5 and an interrupt factor when generating an interrupt to the printer controller 5. is there.

  In these MFP controller area 47, color image processing board area 48, network board area 49, or additional device area 50, the received command version (RxCommandVersion), Tx device ID, and initialization status (Status) are stored. Information necessary for communication is written at the time of communication preparation, and an interrupt factor is written (set) when communication preparation is completed and communication is actually performed.

  The color image processing board area 48 will be described as an example. The received command version is information indicating the version of the command written by the color image processing board 4 in the command area 38 (specifically, the color image processing board command area 40). It can handle the addition of commands. The control unit 25b reads the received command version when preparing for communication, and recognizes the version of the command written in the command area 38. The Tx device ID is an identifier of a device that performs writing in an area in which a received command version or the like is written, and is information indicating the color image processing board 4 here.

  The initialization status includes information indicating that the printer controller 5 is not connected to the PCI bus 2, information indicating that writing of information necessary for communication to the color image processing board area 48 has been completed, or a color image Any of the information indicating that preparation for communication with the processing board 4 has been completed. When the printer controller 5 is not connected, information indicating that is written by the control unit 25b, and the PCI controller 26a of the color image processing board 4 receives information necessary for communication, that is, a received command version and After writing the Tx device ID, the initialization status is rewritten with information indicating that writing of information necessary for communication preparation has been completed. When the control unit 25b of the printer controller 5 determines that information necessary for communication is written from the initialization status, the control unit 25b reads the received command version, and sets the initialization status to information indicating that the communication preparation is completed. rewrite. In this manner, communication preparation is performed between the color image processing board 4 and the printer controller 5. The color image processing board 4 also reads out the command area size and command area 0 offset when preparing for communication.

  By the way, the configuration register built in the PCI controller 26b can be accessed only by the PCI host controller 11 of the MFP controller 3, but in this way, the sub-RAM of the RAM 27b that can be accessed by the PCI controller 26a and the PCI controller 26c. By setting information necessary for communication in the configuration area 37, the color image processing board 4 and the network board 6 acquire information necessary for such communication, and the printer controller 5 does not pass through the host device 3. It is possible to communicate directly with.

  The interrupt factor is information indicating the factor when the color image processing board 4 generates an interrupt to the printer controller 5. Here, as interrupt factors, an interrupt factor (REQ) for requesting reading of a command or response written in the color image processing board command area 40, and a command area of the RAM 27 a of the color image processing board 4 by the printer controller 5 are used. An interrupt factor (ACK) for notifying that the reading of the command or response written in is completed, an interrupt factor (RESET) for requesting the printer controller 5 to reset, and an interrupt factor for achieving synchronization (SYNC) is prepared.

  For example, when the color image processing board 4 writes a command in the color image processing board command area 40 and causes the printer controller 5 to generate an interrupt, the PCI controller 26 a causes the interrupt factor (REQ) in the color image processing board area 48. "1" is written in the interrupt control register 12, and an interrupt request to the printer controller 5 is written in the interrupt control register 12. In response to this, an interrupt signal is transmitted from the interrupt control register 12 to the control unit 25 b of the printer controller 5 through the interrupt signal line 18. In response to this, the control unit 25b searches the sub-configuration area 37 for an area where “1” is set as an interrupt factor. When it is detected that “1” is set as the interrupt factor (REQ) of the color image processing board area 48, it is determined that the command is written in the color image processing board command area 40, and the color A command is read from the image processing board command area 40, and processing corresponding to the command is executed. Then, the interrupt factor is cleared. That is, the interrupt factor (REQ) is rewritten from “1” to “0”.

  Thus, in the color image processing board area 48, information necessary for the color image processing board 4 to communicate with the printer controller 5 is written by the PCI controller 26a of the color image processing board 4. Yes. The received command version, Tx device ID, and initialization status are written at the stage of communication preparation as described above.

  The MFP controller area 47 and the network board area 49 are also written with the same information except that the writing device is different. Such a subconfiguration area is also provided in the memory (RAM) of all the devices 3 to 6, but the subconfiguration area of any device has the same configuration and is received by the subconfiguration area. Since only the combination of devices for writing the command version, Tx device ID, etc. is different, the description of the subconfiguration areas of the other devices 3, 4, and 6 is omitted.

  FIG. 5 is a diagram illustrating a unit management area 23 provided in the RAM 13 of the MFP controller 3 which is a host device. As illustrated, the unit management area 23 includes a unit management information area 52, an MFP controller device information area 53, a color image processing board device information area 54, a printer controller device information area 55, and a network board. A device information area 56 and a device information area 57 for additional devices are logically divided.

  In the unit management information area 52, the host status and the command area size are written by the PCI host controller 11. The host status is information indicating that the MFP controller 3 is executing initialization processing (configuration) of the slave devices 4 to 6, or the MFP controller 3 has completed initialization processing of all the slave devices 4 to 6. It is one of the information indicating that it has been done. The command area size is information indicating the size (capacity) of the command area 22 provided in the RAM 13.

  An MFP controller device information area 53, a color image processing board device information area 54, a printer controller device information area 55, and a network board device information area 56 include a device ID, a unit number, and a status. The sub-configuration area PCI memory space address and the like are written by the PCI host controller 11.

  The device ID and unit number are information acquired by the PCI host controller 11 from the subconfiguration area of the slave device. The status is one of information indicating that the slave device has not been detected or information indicating that the slave device has been detected, that is, the initialization processing of the slave device has been completed. . The subconfiguration area PCI memory space address is the head address on the PCI memory space of the subconfiguration area provided in the RAM 27 of the slave device.

  For example, the PCI host controller 11 completes the configuration (initialization process) of the configuration register built in the PCI controller 26b of the printer controller 5, and the received command version, Tx device ID, and Information indicating that the initialization is completed is written as an initialization status. Next, the device information acquired from the subconfiguration area 37, that is, the device ID, the unit number, and the subconfiguration area PCI memory space address of the subconfiguration area 37 are written in the device information area 55 for the printer controller. Then, information indicating detection is written as the status. When information necessary for accessing the printer controller 5 is set in the printer controller device information area 55 of the unit management area 23 in this way, the slave device (the color image processing board 4 or the network board 6) The sub-configuration area 37 of the printer controller 5 can be accessed with reference to the information written in the controller device information area 55. That is, it is possible to recognize the printer controller 5 and prepare for communication with the printer controller 5 as described above.

  Hereinafter, processing operations performed by the MFP controller 3 serving as the host device in the configuration cycle when the communication system 1 is activated will be described with reference to the flowchart shown in FIG. 6 and FIG. Note that the processing operation of the MFP controller 3 described based on the flowchart shown in FIG. 6 is performed according to a command issued by the control unit 10 based on a program stored in a ROM (not shown). Here, the case where the first slave device is the printer controller 5 and the second slave device is the color image processing board 4 will be mainly described. However, the combination of the first slave device and the second slave device is described here. It is not limited. That is, the combination of the first slave device and the second slave device is arbitrary. For example, the first slave device may be the color image processing board 4 and the second slave device may be the printer controller 5.

  The PCI host controller 11 of the MFP controller 3 monitors whether or not a slave device is connected to the PCI bus 2 in the configuration cycle when the communication system 1 is activated, and determines whether or not a slave device has been detected (S1). . As described above, the PCI host controller 11 of the MFP controller 3 detects the printer controller 5 (first slave device) connected to the PCI bus 2.

  Here, if the PCI host controller 11 determines that the printer controller 5 has been detected (S1: YES), the PCI host controller 11 executes configuration (S2). Specifically, the configuration register 60 built in the PCI controller 26b is accessed to write the base address and read the device ID, version information, and the like. Note that the configuration for the configuration register 60 performed here conforms to the PCI standard, and thus detailed description thereof is omitted.

  Subsequently, the PCI host controller 11 sets the device information acquired from the printer controller 5 by the configuration of S2 in the unit management area 23 (S3). The MFP controller 3 includes a RAM 13 provided with a unit management area 23 for storing device information acquired from the printer controller 5. The PCI host controller 11 includes a device ID acquired from the configuration register 60 in S2, The unit number and the address (start address) in the PCI memory space of the sub-configuration area 37 provided in the RAM 27 b of the printer controller 5 are written in the printer controller device information area 55 in the unit management area 23. Then, the status in the printer controller device information area 55 is rewritten with information indicating that the printer controller 5 has been detected.

  Next, the PCI host controller 11 determines whether there is a slave device whose configuration has not been completed (S4). That is, it is determined whether there is a slave device that has not performed the processing operations of S2 and S3. This determination process can be determined by referring to the statuses of the device information areas 53 to 56 in the unit management area 23. If it is determined that there is a slave device that has not been configured (S4: YES), the printer controller 5 has been described as an example for the slave device (color image processing board 4 or network board 6). Similarly to the above, the processing operations of S2 and S3 are performed.

  Conversely, when it is determined that there is no slave device that has not been configured (S4: NO), that is, here, for all the device information areas 53 to 56, the device ID, unit number, and subconfiguration area If it is determined that the writing of the PCI memory space address and the status change have been completed, the process proceeds to S5.

  That is, the PCI host controller 11 writes the unit management address in the sub-configuration area of each slave device and notifies each slave device of the completion of configuration (S5). In other words, each slave device is notified that information necessary for accessing the detected slave device has been acquired.

  Specifically, the unit management address which is the head address of the unit management area 23 is written in the device information area 46 in the sub-configuration area 37 to the printer controller 5 and the status of the device information area 46 is configured ( It is rewritten with information indicating that the initialization process has been completed. Then, the same processing as that performed for the sub-configuration area 37 of the printer controller 5 is performed in the sub-configuration areas (respectively provided in the RAM 27a of the color image processing board 4 and the RAM 27c of the network board 6). (Not shown).

  As described above, the PCI host controller 11 of the MFP controller 3 performs a series of processing operations from S2 to S5 to obtain device information necessary for accessing the detected first slave device (for example, the printer controller 5). Obtained from the first slave device and notifies the second slave device (for example, the color image processing board 4) to that effect.

  As is apparent from the above description, for example, the control unit 25a of the color image processing board 4 reads the unit management address from the subconfiguration area provided in the RAM 27a, and is provided in the RAM 13 of the MFP controller 3 by the PCI controller 26a. The unit management area 23 can be accessed. The device ID, unit number, and subconfiguration area PCI memory space address of the printer controller 5 can be acquired from the printer controller device information area 55 in the unit management area 23. Further, the device ID, unit number, and subconfiguration area PCI memory space address of the network board 6 can be acquired from the network board device information area 56. That is, information necessary for accessing the printer controller 5 and the network board 6 can be easily obtained from the host device 3.

  Next, processing operations performed in the slave device when the completion of configuration is notified as described above will be described based on the flowcharts shown in FIGS. The processing operation shown in the flowchart of FIG. 8 is performed in all slave devices of the color image processing board 4, the printer controller 5, and the network board 6. Here, the color image processing board 4 performs the processing shown in FIG. The case of performing the operation will be described below as an example. The processing operation of the color image processing board 4 described based on the flowchart shown in FIG. 8 is performed according to a command issued by the control unit 25a based on a program stored in a ROM (not shown) provided in the color image processing board 4. Done.

  First, the control unit 25a of the color image processing board 4 determines whether a configuration completion notification has been received (S11). Specifically, although not shown, the unit management address is written in the device information area of the sub-configuration area provided in the RAM 27a, and the status of the device information area indicates that the configuration (initialization process) has been completed. It is determined whether or not the information has been rewritten.

  Here, when it is determined that there is a configuration completion notification (S11: YES), that is, the unit management address is written in the device information area, and the status is rewritten with information indicating that the configuration is completed. If it is determined, the unit management area 23 of the host device 3 is accessed (S12). That is, the control unit 25a reads the unit management address written in the device information area, and the PCI controller 26a accesses the unit management address read by the control unit 25a, that is, the unit management area 23 of the RAM 13.

  Next, the PCI controller 26a of the color image processing board 4 acquires device information of other devices, that is, the MFP controller 3, the printer controller 5, and the network board 6 (S13). Specifically, the device ID, unit number, and sub-configuration area from the MFP controller device information area 53, the printer controller device information area 55, and the network board device information area 56 in the accessed unit management area 23 are displayed. Read the PCI memory space address.

  As described above, when the second slave device (color image processing board 4) receives a configuration completion notification, that is, a notification indicating that device information has been acquired from the first slave device (printer controller 5), Device information is acquired from the host device (MFP controller 3). Note that the PCI controller 26a of the color image processing board 4 acquires device information from the host device 3 by reading the device information from the unit management area 23 of the RAM 13 when receiving the above notification. Device information of other devices can be easily acquired.

  Subsequently, the PCI controller 26a of the color image processing board 4 accesses another device based on the acquired device information and prepares for communication with the device (S14). For example, the sub-configuration area 37 provided in the RAM 27b of the printer controller 5 is accessed based on the device ID, unit number, and sub-configuration area PCI memory space address read from the printer controller device information area 55. Then, the received command version and the Tx device ID (device ID of the color image processing board 4) are written in the area dedicated to the own device 4 in the subconfiguration area 37, that is, the color image processing board area 48.

  As described above, the PCI controller 26a of the color image processing board 4 (second slave device) accesses the printer controller 5 (first slave device) based on the acquired device information and communicates with the printer controller 5. Make preparations.

  By the way, the printer controller 5 has a RAM 27b in which an area for writing information to other devices connected to the self device 5 is provided for each other device, in other words, a sub-configuration area 37 as shown in FIG. The PCI controller 26a of the color image processing board 4 communicates with an area (color image processing board area 48) dedicated to the color image processing board 4 provided in the RAM 27b of the printer controller 5. Communication preparation is performed by writing necessary information and reading information such as a command area size and a command area 0 offset from the device information area 46.

  Then, the control unit 25a of the color image processing board 4 determines whether there is a target for which communication preparation is not completed after the processing operation of S14 (S15). That is, it is determined whether or not the processing operation of S14 described with reference to the printer controller 5 has been performed for all devices that have acquired device information in S13. If it is determined that there is a target device that is not ready for communication (S15: YES), the processing operation of S14 is performed on the target device. Conversely, if it is determined that there is no target for which communication preparation has not been completed (S15: NO), the processing is completed.

  Note that the processing operation of the flowchart shown in FIG. 8 described by taking the color image processing board 4 as an example is also performed by the printer controller 5, the network board 6, and the MFP controller 3, and the operation between the two devices is performed. Thus, a process for writing information necessary for communication such as a command version and a Tx device ID and a process for reading information necessary for communication such as a command area size and a command area 0 offset are mutually performed. .

  Specifically, the PCI controller 26 a of the color image processing board 4 writes information necessary for communication in the color image processing board area 48 of the subconfiguration area 37 and information necessary for communication from the device information area 46. In parallel with the reading process, the PCI controller 26b of the printer controller 5 writes information necessary for communication to the printer controller area in the sub-configuration area provided in the RAM 27a of the color image processing board 4 and the device information area. A process for reading information necessary for communication is performed.

  In this way, by writing and reading information necessary for communication between two slave devices and preparing for communication, the slave devices communicate directly with each other without going through the host device (MFP controller 3). It becomes possible.

  Hereinafter, as an example of the case where slave devices communicate directly with each other without going through the host device (MFP controller 3), data is transmitted together with commands from the color image processing board 4 on the command transmission side to the printer controller 5 on the command reception side. Communication when small-sized data is transferred will be described with reference to the sequence diagram of FIG. 9 and FIG.

  Note that the processing operation of the color image processing board 4 shown in FIG. 9 is performed according to a command issued by the control unit 25a based on a program stored in a ROM (not shown) provided in the color image processing board 4, and the printer controller 5 This processing operation is performed according to a command issued by the control unit 25b based on a program stored in a ROM (not shown) provided in the printer controller 5.

  First, the control unit 25a of the color image processing board 4 on the command transmission side acquires a semaphore in the command area 40 for the color image processing board of the printer controller 5 on the command reception side. Specifically, information for acquiring the right to use the color image processing board command area 40 is written in a predetermined area of the RAM 27a, and the semaphores of the header area 43 and the data area 44 of the color image processing board command area 40 are set. To win.

  Then, the control unit 25a writes the header type and the command (command number) in the header area 43 of the color image processing board command area 40. Specifically, the PCI controller 26 a sends a command indicating the header type indicating that the color image processing board command area 40 is being used by the command and the handling of data to be transferred to the printer controller 5 to the PCI bus 2. To the PCI controller 26b. On the other hand, the PCI controller 26 b writes the received header type and command into the header area 43 of the color image processing board command area 40 via the local bus 31.

  In this way, the color image processing board 4 writes a command to the color image processing board command area 40 dedicated to the color image processing board 4 provided in the RAM 27b of the printer controller 5 by the PCI controller 26a.

  Subsequently, the control unit 25a writes data to be transferred to the data area 44 of the command area 40 for the color image processing board. Specifically, the PCI controller 26a transmits data to be transferred to the PCI controller 26b via the PCI bus 2. On the other hand, the PCI controller 26b writes the received data into the data area 44 of the color image processing board command area 40 of the RAM 27b via the local bus 31. Here, the command and the data to be transferred are written in the command area 40 for the color image processing board. However, if it is not necessary to transfer data other than the command, the writing to the data area 44 is not necessary. is there.

  When the control unit 25a of the color image processing board 4 writes the command and the data to be transferred in the color image processing board command area 40 in this manner, the control unit 25a notifies the printer controller 5 on the command receiving side of the fact. , Generate an interrupt. Specifically, the PCI controller 26a writes an interrupt factor for causing the printer controller 5 to generate an interrupt in the color image processing board area 48 in the sub-configuration area 37 of the RAM 27b. Specifically, the interrupt factor (REQ) of the color image processing board area 48 is rewritten from “0” to “1”. Then, an interrupt request to the printer controller 5 is written in the interrupt control register 12 provided in the MFP controller 3.

  In this way, when an interrupt request from the color image processing board 4 to the printer controller 5 is set in the interrupt control register 12, the interrupt control register 12 interrupts the control unit 25b of the printer controller 5 via the interrupt signal line 18. A signal is transmitted. In response to this, the control unit 25b searches for an interrupt factor in which “1” is written from the sub-configuration area 37 of the RAM 27b via the local bus 31, and the interrupt factor (in the color image processing board area 48) ( By detecting that “1” is set as (REQ), it can be determined that the command has been written in the command area 40 for the color image processing board.

  The control unit 25 b of the printer controller 5 reads commands from the header area 43 of the color image processing board command area 40 and reads data from the data area 44. Then, processing corresponding to the command read from the header area 43 is executed on the data read from the data area 44, and the command transmission side color that the command and data are read from the command area 40 for the color image processing board is read. In order to notify the image processing board 4, an interrupt is generated for the color image processing board 4. This interrupt is the same as the interrupt from the color image processing board 4 to the printer controller 5 except that the interrupt direction is opposite to that of the interrupt from the color image processing board 4 to the printer controller 5 and the interrupt factor is different. Therefore, detailed description thereof is omitted here.

  When the control unit 25a of the color image processing board 4 receives an interrupt from the printer controller 5, the command and data written in the color image processing board command area 40 are read out by the control unit 25b of the printer controller 5 and are not required. Judge that it became. Then, a header type indicating that the color image processing board command area 40 is unused is written in the header area 43, and information for returning the right to use the color image processing board command area 40 to a predetermined area of the RAM 27a. To return the semaphores of the header area 43 and the data area 44 of the command area 40 for the color image processing board and complete the communication.

  Thus, in the communication system 1 according to the present embodiment, the slave device can easily recognize other slave devices and can directly communicate with each other. Therefore, for example, when color image data having a large data size is transferred between slave devices, the color image data can be efficiently transferred without going through the host device 3.

  Further, the configuration of the communication system 1 shown in the present embodiment is only one aspect of the communication system according to the present invention, and it is needless to say that the design can be changed as appropriate without departing from the gist of the present invention. And a plurality of slave devices can be realized as a copying machine, a facsimile machine, or the like in addition to the multifunction machine described in the present embodiment.

  The present invention is applicable to a communication system in which a host device and a plurality of slave devices are connected by an input / output bus, for example.

It is the block diagram which showed the structural example of the communication system which concerns on embodiment of this invention. FIG. 2 is a diagram schematically illustrating a configuration of a RAM included in an MFP controller. It is a figure for demonstrating a command area. It is the figure which showed the structure of the subconfiguration area. It is the figure which showed the structure of the unit management area. It is the flowchart which showed the processing operation which is performed in the host device at the time of system starting. It is a figure for demonstrating the process in which a slave device acquires the device information of another slave device from a host device. 6 is a flowchart illustrating processing operations performed in a slave device when a configuration completion notification is received. Sequence diagram showing processing operations performed in both devices when a command and data having a small data size are transmitted from the command transmission side to the command reception side, and processing corresponding to the command is performed on the data received by the command reception side It is. It is a figure for demonstrating the communication by which data with small data size are transferred with a command from the command transmission side to the command reception side.

Explanation of symbols

1 Communication system 2 PCI bus (I / O bus)
3 MFP controller (host device)
4 Color image processing board (slave device)
5 Printer controller (slave device)
6 Network board (slave device)
10, 25a, 25b, 25c Control unit 13, 27a, 27b, 27c RAM
21, 37 Sub-configuration area 22, 38 Command area 23 Unit management area 26a, 26b, 26c PCI controller 46 Device information area 47 MFP controller area 48 Color image processing board area 49 Network board area 52 Unit management information area 53 Device information area for MFP controller 54 Device information area for color image processing board 55 Device information area for printer controller 56 Device information area for network board 60 Configuration register

Claims (4)

  In a communication system in which a host device and a plurality of slave devices are connected by an input / output bus, the host device detects a first slave device connected to the input / output bus, and the detected first slave Means for acquiring device information necessary for accessing the device from the first slave device and notifying the second slave device of the device information. When the second slave device receives the notification, Obtaining means for obtaining the device information from the host device; and communication preparation means for accessing the first slave device based on the obtained device information and preparing for communication with the first slave device; A communication system comprising:   The host device includes a memory for storing the device information acquired from the first slave device, and the acquisition unit of the second slave device receives the device information from the memory when receiving the notification. The communication system according to claim 1, wherein the device information is acquired from the host device by reading.   The first slave device includes a memory in which an area for writing information to another device connected to the own device is provided for each of the other devices, and the communication preparation unit of the second slave device 3. The communication preparation is performed by writing information necessary for communication in an area dedicated to the second slave device provided in a memory of the first slave device. Communications system.   The communication system according to any one of claims 1 to 3, wherein the input / output bus is a PCI bus.

Images