SPRUJ79 November 2024 F29H850TU
The global access bridge arbitrates accesses in a round-robin priority. Data access to RAM is accessible from all CPUs, with 9 CPU ports on the RAM controller (two data read ports and one data write port for each CPU). Data accesses are optimized for two CPUs, connected to the MEMSS memory controller directly. Accesses from the remaining CPUs are arbitrated and merged into a generic CPU port with two data read and one data write port. These ports are connected to only one CPU at any given point in time. Figure 3-23 depicts how the LDAn memories are optimized for zero wait states by connecting CPU1 and CPU2 to the direct access port and CPU3 to the global bridge.
At any given time, accesses from one CPU are routed to the other side of the bridge. This global access bridge has only one set of output ports; hence, two different CPUs from bridge cannot access two memory instances concurrently. When a specific CPU is granted access, all active accesses from that CPU are placed into memory simultaneously, helping to support the throughput as shown in Figure 3-24.
The global access bridges available to each RAM are shown by Figure 3-13. The global access bridges support atomic operations and posted write with the write buffer. The posted write support is common for all CPUs.