Granted Patent B2

US 7,389,373 · App. 11/479,969 · Granted Jun 17, 2008

Abstract

Claims (52)

1. Arbitration device, designed to be connected between, on the one hand, a first and a second module and, on the other hand, storing means forming a memory workspace, the device comprising:

means of detecting one or more requests coming, concurrently or not, from the first and second modules, for the purpose of accessing the memory workspace;

selection means generating a selection signal assuming:

a first state, by default or if a single detected request comes from the first module or else if two requests are detected concurrently; and

a second state, if a single detected request comes from the second module or if one of two concurrently detected requests has already been served;

first clock means, activated if the selection signal assumes the first state, and generating a first clock signal enabling the storing means to serve a request coming from the first module;

first reset means, activated if the selection signal assumes the first state, and generating a first reset signal making it possible to erase a request coming from the first module after it has been served;

second clock means, activated if the selection signal assumes the second state, and generating a second clock signal enabling the storing means to serve a request coming from the second module; and

second reset means, activated if the selection signal assumes the second state, and generating a second reset signal, making it possible to erase a request coming from the second module after it has been served.

2. The device in claim 1 , wherein the storing means include at least one SRAM memory.

3. The device in claim 1 , wherein the storing means include at least one register.

4. The device in claim 1 , wherein the detection means include:

a first D flip-flop, whose clock input receives a write enable signal coming from the first module;

a second D flip-flop, whose clock input receives a read signal coming from the first module, or obtained by combining an output enable signal and a memory enable signal coming from the first module;

a third D flip-flop, whose clock input receives a write enable signal coming from the second module;

a fourth D flip-flop, whose clock input receives a read signal coming from the second module, or obtained by combining an output enable signal and a memory enable signal coming from the second module;

and wherein the first reset signal makes it possible to reset the first and second flip-flops, and the second reset signal makes it possible to reset the third and fourth flip-flops.

5. The device in claim 4 , wherein each of the first, second, third and fourth flip-flops has a D input in the “1” state and a non-inverted output whose initial state is “0”, or has a D input in the “0” state and an inverted output whose initial state after inversion is “0”, and wherein the selection means include:

a first OR element, receiving at its input the output signals of the first and second flip-flops;

a second OR element, receiving at its input the output signals of the third and fourth flip-flops;

a first AND element of which an inverted output receives the output signal of the first OR element and a non-inverted input receives the output signal of the second OR element; and

a fifth D flip-flop, whose clock input receives the output signal of the first AND element, and which has a D input in the “1” state and a non-inverted output whose initial state is “O” or has a D input in the “0” state and an inverted output whose initial state after inversion is “0”, the output signal of the fifth flip-flop being said selection signal whose first and second states are “0” and “1”, respectively;

wherein the second reset signal makes it possible to reset the fifth flip-flop.

6. The device in claim 1 , wherein the first, and respectively second clock means include:

a filtering element which, on condition that the selection signal assumes the first, and respectively second state, allows passage of a request signal assuming the “1” state, in order to indicate that a request coming from the first, and respectively second module has been detected;

a first delay element, receiving at its input the output signal of the filtering element;

a second delay element, receiving at its input the output signal of the first delay element;

a second AND element of which an inverted input receives the output signal of the second delay element and a non-inverted input receives the output signal of the first delay element, and generating at its output said first, and respectively second clock signal.

7. The device in claim 6 , wherein the first, and respectively second reset means share said filtering element and said first and second delay elements with the first, and respectively second clock means, and wherein the first, and respectively second reset means further include:

a third delay element, receiving at its input the output signal of the second delay element; and

a third AND element of which an inverted input receives the output signal of the third delay element and a non-inverted input receives the output signal of the second delay element, and generating at its output said first, and respectively second reset signal.

8. The device in claim 6 , wherein the first and second delay elements together apply a total cumulative delay greater than or equal to the minimum clock period with which the storing means can operate.

9. The device in claim 6 , wherein the second delay element applies a delay greater than or equal to the hold time with which the storing means can operate.

10. The device in claim 1 and further comprising a third OR element, receiving at its input the first and second clock signals, and generating at its output a third clock signal for the storing means.

11. The device in claim 1 and further comprising:

a sixth D flip-flop, whose D input is designed to receive a first output data signal coming from the storing means, and whose clock input receives the first clock signal, and which generates at it output a second output data signal intended for the first module; and

a seventh D flip-flop, whose D input is designed to receive said first output data signal coming from the storing means, and whose clock input receives the second clock signal, and which generates at its output a third output data signal intended for the second module.

12. The device in claim 1 and further comprising at least one multiplexing means, each multiplexing means being such that:

it makes it possible to provide a separate control signal to the storing means;

it receives at its input a first control signal coming from the first module and a second control signal coming from the second module; and

it is controlled by said selection signal with the result being that:

if the selection signal assumes the first state, the multiplexing means generates at its output said first control signal; and

if the selection signal assumes the second state, the multiplexing means generates at its output the second control signal.

13. The device in claim 12 , wherein said control signal belongs to the group comprising:

an address signal;

an input data signal;

a write enable signal;

an output enable signal;

a memory enable signal; and

a read signal.

14. The device of claim 1 , wherein the first and second modules comprise respectively a processing unit and an IP block of a microcontroller.

15. A microcontroller comprising an arbitration device as claimed in claim 1 .

Assignments (11)