Access control device and access control method

1. An access control device for controlling access to a first device connected with a first bus conforming to a first standard, said first device conforming to said first standard and access to a second device connected with said first bus, said second device conforming to a second standard, said access control device comprising:

a first signal generator which generates a first transaction start signal indicating start of a transaction for said first device; and

a second signal generator which generates a second transaction start signal for said second device based on said first transaction start signal,

wherein the first signal generator generating the first transaction start signal and the second signal generator generating the second transaction start signal are adapted to and result in the first device communicating with the second device without employing a first standard-second standard bridge even though the first device conforms to the first standard and the second device conforms to the second standard, the second standard being different than the first standard, where otherwise the first device is unable to communicate with the second device due to the second standard being different than the first standard.

2. The access control device according to claim 1 , wherein said second signal generator generates said second transaction start signal upon occurrence of an access to said second device.

3. The access control device according to claim 1 , wherein said second signal generator suspends generating said second transaction start signal upon occurrence of an access to said first device.

4. The access control device according to claim 1 , wherein said second signal generator includes an address judgment unit which judges whether or not an address of a device to be accessed accords with an address of said second device and a gate unit which can generate said second transaction start signal based on said first transaction start signal and a judgment of said address judgment unit and can outputs said second transaction start signal to said second device.

5. The access control device according to claim 1 , wherein said first bus is a PCI (Peripheral Component Interconnect) bus.

6. The access control device according to claim 5 , wherein said first transaction start signal is a first FRAME signal.

7. The access control device according to claim 6 , wherein said second signal generator judges whether or not an address stored in a CONFIG ADDRESS register accords with an address of said second device and can generate a second FRAME signal for said second device based on said first FRAME signal and a judgment thereof.

8. The access control device according to claim 1 , wherein a plurality of said second devices are connected with said first bus, and said second signal generator generates said second transaction start signal for a second device to be accessed in said plurality of second devices.

9. The access control device according to claim 8 , wherein said second signal generator includes an address judgment unit which judges whether or not an address of a device to be accessed accords with an address of each of said plurality of second devices and a gate unit which can generate said second transaction start signal for said second device to be accessed based on said first transaction start signal and a judgment of said address judgment unit and can output said second transaction start signal to said second device.

10. An access control method for controlling an access to a second device conforming to a second standard, said second device being connected with a first bus conforming to a first standard, the method comprising:

generating a first transaction start signal for a first device conforming to said first standard and connecting with said first bus; and

generating a second transaction start signal for said second device based on said first transaction start signal,

wherein generating the first transaction start signal and generating the second transaction start signal are adapted to and result in the first device communicating with the second device without employing a first standard-second standard bridge even though the first device conforms to the first standard and the second device conforms to the second standard, the second standard being different than the first standard, where otherwise the first device is unable to communicate with the second device due to the second standard being different than the first standard.

11. The access control method according to claim 10 , wherein said second transaction start signal is generated upon occurrence of an access to said second device.

12. The access control method according to claim 10 , wherein generation of said second transaction start signal is suspended upon occurrence of an access to said first device.

13. The access control method according to claim 10 , wherein said generating a second transaction start signal includes judging whether or not an address of a device to be accessed accords with an address of said second device, generating said second transaction start signal based on said first transaction start signal and matching of said addresses, and outputting said second transaction start signal to said second device.

14. The access control method according to claim 10 , wherein said first bus is a PCI (Peripheral Component Interconnect) bus.

15. The access control method according to claim 14 , wherein said first transaction start signal is a first FRAME signal.

16. The access control method according to claim 15 , wherein said generating a second transaction start signal includes judging whether or not an address stored in a CONFIG ADDRESS register accords with an address of said second device and generating a second FRAME signal for said second device based on said first FRAME signal and matching of said addresses.

17. The access control method according to claim 10 , wherein a plurality of said second devices are connected with said first bus, and said second transaction start signal for a second device to be accessed in said plurality of second devices is generated.

18. The access control method according to claim 10 , wherein a plurality of said second devices are connected with said first bus, and

said generating a second transaction start signal includes judging whether or not an address of a device to be accessed accords with an address of each of said plurality of second devices, generating said second transaction start signal for said second device to be accessed based on said first transaction start signal and matching of said addresses, and outputting said second transaction start signal to said second device.