Method of arbitrating access to a data bus
First Claim
1. A method of arbitrating access to a data bus among bus devices, wherein the bus devices are linked by a plurality of arbitration rings, comprising:
- a) requesting access by a first one of the bus devices;
b) checking whether a first signal, which indicates that one of the arbitration rings is enabled, is applied to an input of the first one of the bus devices;
c) if the first signal is applied, outputting a second signal by the first one of the bus devices;
d) checking whether, at the end of a predetermined time interval, the first signal is still applied at the input of the first one of the bus devices; and
e) if the first signal is still applied at the end of the predetermined time interval, accessing the data bus by the first one of the bus devices;
wherein a respective priority is assigned to each of the arbitration rings.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for arbitrating access to a data bus among subscribers or bus devices (Tn 1, Tn 2, . . . ), wherein the bus devices are coupled by at least one arbitration ring (12; 38, 40, 42, 44, 46, 48). The method comprises the following steps: a) requesting access by a first bus device; b) checking whether a first signal, which indicates that the arbitration ring is enabled, is present at an input (16) of the first bus device; c) if the first signal is present, outputting (18) a second signal by the first bus device; d) checking whether, at the end of a predetermined time period, the first signal is still present at the input (16) of the first bus device; and e) if the first signal is still present at the end of the predetermined time period, accessing the data bus by the first bus device.
-
Citations
9 Claims
-
1. A method of arbitrating access to a data bus among bus devices, wherein the bus devices are linked by a plurality of arbitration rings, comprising:
-
a) requesting access by a first one of the bus devices;
b) checking whether a first signal, which indicates that one of the arbitration rings is enabled, is applied to an input of the first one of the bus devices;
c) if the first signal is applied, outputting a second signal by the first one of the bus devices;
d) checking whether, at the end of a predetermined time interval, the first signal is still applied at the input of the first one of the bus devices; and
e) if the first signal is still applied at the end of the predetermined time interval, accessing the data bus by the first one of the bus devices;
wherein a respective priority is assigned to each of the arbitration rings. - View Dependent Claims (2, 3, 4)
-
-
5. A bus device for accessing a data bus and for coupling to a plurality of arbitration rings, wherein a priority is assigned to each arbitration ring, comprising:
-
a) a requestor configured to request access to the data bus;
b) a first checker configured to check whether a first signal, which indicates that one of the arbitration rings is enabled, is applied to an input of a first one of the bus devices;
c) a first output device configured to output a second signal by the first one of the bus devices, if the first signal is applied;
d) a second checker configured to check whether, at the end of a predetermined time interval, the first signal is still applied at the input of the first one of the bus devices; and
e) an access device configured to access the data bus by the first one of the bus devices, if the first signal is still applied at the end of the predetermined time interval. - View Dependent Claims (6, 7, 8)
-
-
9. A communication system, comprising:
-
a plurality of bus devices; and
at least one arbitration ring to couple the bus devices;
wherein each of the bus devices comprises;
a) a requestor configured to request access to a data bus;
b) a first checker configured to check whether a first signal, which indicates that one of the arbitration rings is enabled, is applied to an input of a first one of the bus devices;
c) an output device configured to output a second signal by the first one of the bus devices, if the first signal is applied;
d) a second checker configured to check whether, at the end of a predetermined time interval, the first signal is still applied at the input of the first one of the bus devices; and
e) an access device configured to access the data bus by the first one of the bus devices, if the first signal is still applied at the end of the predetermined time interval.
-
Specification