2.3.5 COM asynchronous bridge

The SDC-600 COM asynchronous bridge module is used as a connection between the External component and the Internal APBCOM when they are in different power or clock domains.

The bridge synchronizes the inputs coming from the clock domain of the other side. This module transfers and synchronizes data bytes between different domains using four-way handshake signals.

The bridge is available in two versions:

Direct COM Asynchronous bridge

For this area-optimized bridge, the data is not registered on either side of the bridge. The sideband signals are not registered on the sending side, but only synchronized on the receiving side of the bridge.

It has two CWIs on each side of the domains: one for the Rx and one for the Tx.

This bridge has two clock LPI interfaces, one for each clock domain.

Note:

If there are multiple domain crossings, you must use Indirect Bridges.

The following figure shows the high-level blocks and transactions between the components when using a Direct Bridge:

Figure 2-8 COM Asynchronous Direct Bridge high-level block diagram
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Indirect COM Asynchronous bridge

For the Indirect Bridge, data is registered on both sides of the bridge. Sideband signals are all registered on the sending side and synchronized on the receiving side of the bridge. This is done to simplify constraining the CWI and floorplanning at the domain crossings.

The Indirect Bridge can be instantiated multiple times on a CWI channel if passing multiple domains. This bridge has two clock LPI interfaces and two power LPI interfaces to facilitate integration with multiple domain crossings.

The following figure shows the high-level blocks and transactions between the components when using an Indirect Bridge:

Figure 2-9 COM Asynchronous Indirect Bridge high-level block diagram
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