Configurable address decoder
An address decoder for a system is disclosed that can be used for different source nodes in the system. Each address decoder can be configured to perform a plurality of decode methods that can be customized for each source node. A first decode method can be used to determine a target node from a plurality of target nodes based on a destination address of the transaction. A second decode method can be used to assign a dedicated target node as the target node irrespective of the destination address of the transaction. The second decode method can be used to route the transaction to the dedicated target node for testing and verification operations.
1. A system comprising:
a plurality of source nodes configured to issue transactions;
a plurality of address decoders, each address decoder associated with a respective source node from the plurality of source nodes;
one or more interconnects coupled to the plurality of address decoders; and
a plurality of target nodes coupled to the one or more interconnects,
wherein each address decoder from the plurality of address decoders comprises:
a memory configured to store an internal configuration for the address decoder;
a decode windows selection circuit coupled to the memory, and having a decode windows selection circuit output configured to output a set of decode windows based on the internal configuration, wherein the set of decode windows corresponds to a set of target nodes in the plurality of target nodes that a source node associated with a given address decoder is allowed to access;
a decode method selection circuit coupled to the memory, and having a decode method selection circuit output configured to output a determination of a target node associated with a decode method for a transaction issued by the source node based on the internal configuration and the set of decode windows; and
a target identifier (ID) generation circuit coupled to the memory and the decode method selection circuit, and having a target ID generation circuit output configured to output a target node ID associated with the target node of the decode method, wherein the target node ID is used to route the transaction to the target node, and
wherein the one or more interconnects are configured to direct the transaction to the target node based on the target node ID.
2. The system of claim 1 , wherein a default configuration stored in the memory of each address decoder is overwritten in hardware at reset of the system with an override configuration associated with the source node for the given address decoder, and wherein the internal configuration used by the decode method selection circuit is the override configuration.
3. The system of claim 1 , wherein the decode method is one of a plurality of decode methods, and wherein the plurality of decode methods includes a first decode method that outputs the determination of the target node based on a destination address of the transaction being within a decode window from the set of decode windows.
4. The system of claim 3 , wherein the plurality of decode methods includes a second decode method associated with a dedicated target node that is used as the target node irrespective of the destination address of the transaction.
5. An integrated circuit, comprising:
a decode windows selection circuit configured to output a set of decode windows that corresponds to a set of target nodes that a source node is allowed to access;
a decode method selection circuit coupled to the decode windows selection circuit, and configured to output a determination of a target node associated with a decode method for a transaction issued by the source node based on an internal configuration stored in a memory of the integrated circuit, and based on the set of decode windows; and
a target identifier (ID) generation circuit coupled to the decode method selection circuit, and configured to output a target node ID associated with the target node of the decode method, wherein the target node ID is used to route the transaction to the target node.
6. The integrated circuit of claim 5 , wherein the integrated circuit corresponds to an address decoder associated with the source node in a system, and wherein the address decoder is one of a plurality of address decoders associated with source nodes in the system.
7. The integrated circuit of claim 5 , wherein at reset of the integrated circuit, a default configuration stored in the memory of the integrated circuit is replaced with an override internal configuration associated with the source node.
8. The integrated circuit of claim 5 , wherein the target node ID is used by an interconnect coupled to the integrated circuit and coupled to the target node to route the transaction to the target node.
9. The integrated circuit of claim 5 , wherein the decode method is one of a plurality of decode methods.
10. The integrated circuit of claim 9 , wherein the plurality of decode methods includes a first decode method that outputs the determination of the target node based on a destination address of the transaction corresponding to a decode window from the set of decode windows.
11. The integrated circuit of claim 9 , wherein the plurality of decode methods includes a second decode method associated with a dedicated target node that is used as the target node irrespective of a destination address of the transaction.
12. The integrated circuit of claim 11 , wherein the transaction is issued using an Advanced extensible Interface (AXI) protocol and transaction information of the transaction includes AXI USER bits, and wherein the dedicated target node is assigned based on the AXI USER bits.
13. The integrated circuit of claim 5 , wherein the target ID generation circuit is further configured to override the target node ID based on an indication in the internal configuration irrespective of the decode method.
14. The integrated circuit of claim 5 , wherein the set of decode windows is one of a plurality of decode windows, and wherein each decode window in the plurality of decode windows represents an address range associated with a corresponding target node from a plurality of target nodes.
15. The integrated circuit of claim 14 , wherein the decode windows selection circuit is configured to output the set of decode windows from the plurality of decode windows based on a set of parameters associated with the source node.
16. The integrated circuit of claim 5 , wherein the source node is coupled to the target node via a plurality of interconnects.
17. The integrated circuit of claim 16 , wherein a first interconnect in the plurality of interconnects is coupled to a second interconnect in the plurality of interconnects via an interconnect address decoder.
18. The integrated circuit of claim 17 , wherein the target node ID identifies the interconnect address decoder.
19. The integrated circuit of claim 5 , wherein the internal configuration includes a target node windows control register storing decode window enable bits.
20. The integrated circuit of claim 5 , wherein the internal configuration includes a source node parameters register storing decode window selection bits.