SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
The 128-bit memory controller enables zero wait states on program accesses. This also allows data accesses, providing the ability to copy code, download code, and insert software breakpoints. Data accesses can be one or more wait states. Each logical block of the 128-bit memory has four memory banks. The data width of these RAMs is 39 bits (32-bit data and 7-bit ECC). The four banks are grouped together and the addresses are interleaved to form a 128-bit word. All data reads are treated as 64-bit reads, and 64-bit data is returned because the dataline buffer is 64-bit wide.
The 128-bit memory controllers have accesses from the following initiators:
Figure 3-14 shows a view of the 128-bit memory.
Figure 3-15 shows the 128-bit memory controller. This controller implements LPx and CPx memories. Each instance of the controller is optimized for zero wait states from two specific CPUs (CPUa and CPUb). For example, LPAx is optimized for CPU1 and CPU2 program access while CPAx is optimized for CPU1 and CPU3 program access. For these configurations, the controller is the same but the CPUs that get connected as CPUa and CPUb are different.
The 128-bit controller has fast and slow access ports. Fast access ports have zero wait state program access from CPUa and CPUb. Slow access ports are intended for non-critical data access and have one wait state due to pipelining. Lookahead reads using the RTDMA burst signaling is supported on slow access ports.
The read-modify write operation happens in the background without stalling the CPU, using the write buffer close to the memory.
Data accesses from CPUs other than CPUa and CPUb are routed through global access bridge. Debug access is routed through debug access bridge. The latency of these accesses is three wait states. Two wait states are introduced by the global access bridge for data access and debug access bridge for debug access with additional one wait state introduced by the slow access port of 128-bit memory controller.
The following is the round-robin priority order: