Multiple master buses and slave buses transmitting simultaneously

• US 7,305,510 B2
• Filed: 06/25/2004
• Issued: 12/04/2007
• Est. Priority Date: 06/25/2004
• Status: Active Grant

• Current Assignee: VIA Technologies Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Miller, William V.
• Primary Examiner(s): Kindred; Alford
• Assistant Examiner(s): Unelus; Ernest
• Application Number:
  US10/877,376
• Publication Number:
  US 20050289268A1
• Time in Patent Office: 1,257 Days
• Field of Search: 710/240, 710/113, 710/305, 710/306, 710/107, 710/108, 710/200
• US Class Current: 710/305
• CPC Class Codes: G06F 13/4054 where the function is bus cycle extension, e.g. to meet the timing requirements of the target bus

Abstract

A bus system, such as an internal bus system located within a digital device, is disclosed herein. The bus system comprises a plurality of master buses, each master bus connected to at least one master. The bus system also comprises a multi-bus interface connected to the plurality of master buses and a slave bus connected to the multi-bus interface. The multi-bus interface enables one master bus at a time to access the slave bus. Also disclosed herein are bus structures and methods for interfacing between master buses and slave buses.

Claims

1. An internal bus structure comprising:

a plurality of master buses;

a plurality of masters, wherein each master bus is directly connected to two or more of the plurality of masters;

a plurality of slave buses;

at least one slave connected to each slave bus; and

a plurality of multi-bus interfaces corresponding to the slave buses, wherein each multi-bus interface is directly connected to one respective slave bus, each multi-bus interface multiplexing the plurality of master buses to the respective slave bus, wherein each multi-bus interface comprises;

a multi-bus arbiter having a plurality of inputs, each input corresponding to a respective master bus; and

a bridge connected between the multi-bus arbiter and the respective slave bus;

wherein the multi-bus arbiter further comprises;

a plurality of request buffers corresponding to the plurality of master buses, each request buffer capable of storing requests from a respective master bus;

a request selecting multiplexer having a first set of inputs configured to receive the requests directly from the plurality of master buses and a second set of inputs configured to receive the requests stored in the request buffers; and

a request phase arbiter configured to receive the requests from the plurality of master buses, provide a selection signal to the request selecting multiplexer for selecting a request from among the first set of inputs and second set of inputs, and provide a pending signal;

a data phase arbiter configured to receive the selection signal from the request phase arbiter, receive a wait signal from the slave bus, and output a data selection signal;

wait signal decode logic configured to receive the pending signal from the request phase arbiter, receive the wait signal from the slave bus, receive the data selection signal from the data phase arbiter, and output feedback wait signals to the plurality of master buses;

a write multiplexer configured to receive write signals from the plurality of master buses, receive the data selection signal from the data phase arbiter to select one of the write signals, and output the selected write signal to the slave bus; and

a read demultiplexer configured to receive a read signal from the slave bus, receive the data selection signal from the data phase arbiter to select one of the plurality of master buses to which the read signal is to be transferred, and output the read signal to the selected master bus.

2. An internal bus structure comprising:

a plurality of master buses;

a plurality of masters, wherein each master bus is directly connected to two or more of the plurality of masters;

a plurality of slave buses;

at least one slave connected to each slave bus; and

a plurality of multi-bus interfaces corresponding to the slave buses, wherein each multi-bus interface is directly connected to one respective slave bus, each multi-bus interface multiplexing the plurality of master buses to the respective slave bus, wherein each multi-bus interface comprises;

a multi-bus arbiter having a plurality of inputs, each input corresponding to a respective master bus; and

a bridge connected between the multi-bus arbiter and the respective slave bus;

a plurality of request buffers corresponding to the plurality of master buses, each request buffer capable of storing requests from a respective master bus;

a request selecting multiplexer having a first set of inputs configured to receive the requests directly from the plurality of master buses and a second set of inputs configured to receive the requests stored in the request buffers; and

a request phase arbiter configured to receive the requests from the plurality of master buses, provide a selection signal to the request selecting multiplexer for selecting a request from among the first set of inputs and second set of inputs, and provide a pending signal, wherein the request phase arbiter comprises;

a sampled request circuit;

a previous ownership circuit; and

a selection combinational logic circuit configured to receive a sampled request signal from the sampled request circuit and a previous owner signal from the previous ownership circuit, the selection combinational logic circuit further configured to output said pending signal and said selection signal.

3. The internal bus structure of claim 2, wherein the sampled request circuit includes a plurality of request inputs corresponding to the plurality of master buses, the sampled request signal output from the sampled request circuit including one bit for each master bus, and wherein the previous ownership signal output from the previous ownership circuit includes an encoded signal representing which one of the master buses was the previous owner of the slave bus.

4. An internal bus structure comprising:

a plurality of master buses;

at least one master connected to each master bus;

a plurality of slave buses;

at least one slave connected to each slave bus; and

a plurality of multi-bus interfaces each multi-bus interface corresponding to a respective slave bus, each multi-bus interface multiplexing the plurality of master buses to the respective slave bus;

wherein each multi-bus interface comprises a multi-bus arbiter having a plurality of inputs respectively corresponding to the plurality of master buses; and

wherein the multi-bus arbiter of each multi-bus interface comprises;

a plurality of request buffers corresponding to the plurality of master buses, each request buffer capable of storing requests from a respective master bus;

a request selecting multiplexer having a first set of inputs configured to receive the requests directly from the plurality of master buses and a second set of inputs configured to receive the requests stored in the request buffers;

a request phase arbiter configured to receive the requests from the plurality of master buses, provide a selection signal to the request selecting multiplexer for selecting a request from among the first set of inputs and second set of inputs, and provide a pending signal;

a data phase arbiter configured to receive the selection signal from the request phase arbiter, receive a wait signal from the slave bus, and output a data selection signal;

wait signal decode logic configured to receive the pending signal from the request phase arbiter, receive the wait signal from the slave bus, receive the data selection signal from the data phase arbiter, and output feedback wait signals to the plurality of master buses;

a write multiplexer configured to receive write signals from the plurality of master buses, receive the data selection signal from the data phase arbiter to select one of the write signals, and output the selected write signal to the slave bus; and

a read demultiplexer configured to receive a read signal from the slave bus, receive the data selection signal from the data phase arbiter to select one of the plurality of master buses to which the read signal is to be transferred, and output the read signal to the selected master bus.

5. The internal bus structure of claim 4, wherein the request phase arbiter comprises:

a sampled request circuit;

a previous ownership circuit; and

a selection combinational logic circuit configured to receive a sampled request signal from the sampled request circuit and a previous owner signal from the previous ownership circuit, the selection combinational logic circuit further configured to output said pending signal and said selection signal.

6. The internal bus structure of claim 5, wherein the sampled request circuit includes a plurality of request inputs corresponding to the plurality of master buses, the sampled request signal output from the sampled request circuit including one bit for each master bus, and wherein the previous ownership signal output from the previous ownership circuit includes an encoded signal representing which one of the master buses was the previous owner of the slave bus.

7. The internal bus structure of claim 4, further comprising a plurality of bus arbiters, each bus arbiter corresponding to a respective master bus for providing a first level of arbitration for arbitrating requests from the at least one master on the respective master bus to grant ownership of the master bus to one of the at least one requesting master.

8. The internal bus structure of claim 7, wherein the first multi-bus interface and the second multi-bus interface provide a second level of arbitration for granting ownership of the respective slave bus.

9. An internal bus structure comprising:

a plurality of master buses;

at least one master connected to each master bus;

a plurality of slave buses;

at least one slave connected to each slave bus; and

a plurality of multi-bus interfaces each multi-bus interface corresponding to a respective slave bus, each multi-bus interface multiplexing the plurality of master buses to the respective slave bus;

wherein each multi-bus interface comprises a multi-bus arbiter having a plurality of inputs respectively corresponding to the plurality of master buses; and

wherein the multi-bus arbiter of each multi-bus interface comprises;

a plurality of request buffers corresponding to the plurality of master buses, each request buffer capable of storing requests from a respective master bus;

a request selecting multiplexer having a first set of inputs configured to receive the requests directly from the plurality of master buses and a second set of inputs configured to receive the requests stored in the request buffers;

a request phase arbiter configured to receive the requests from the plurality of master buses, provide a selection signal to the request selecting multiplexer for selecting a request from among the first set of inputs and second set of inputs, and provide a pending signal;

wherein the request phase arbiter comprises;

a sampled request circuit;

a previous ownership circuit; and

a selection combinational logic circuit configured to receive a sampled request signal from the sampled request circuit and a previous owner signal from the previous ownership circuit, the selection combinational logic circuit further configured to output said pending signal and said selection signal.

10. The internal bus structure of claim 9, wherein the sampled request circuit includes a plurality of request inputs corresponding to the plurality of master buses, the sampled request signal output from the sampled request circuit including one bit for each master bus, and wherein the previous ownership signal output from the previous ownership circuit includes an encoded signal representing which one of the master buses was the previous owner of the slave bus.