SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
The 64-bit LDx and CDx memory controller is similar to the 128-bit LPx and CPx memory controller, but differs in a few ways. The 64-bit memory controller has zero wait states on data access and one wait state on program access. Each block of 64-bit memory has two memory banks. The data width of these RAMs is 39 bits (32-bit data and 7-bit ECC). The two banks are grouped together and the addresses are interleaved to form a 64-bit word.
Fast access ports have zero wait states for program and data access from CPUa and CPUb. For example, LDAx RAM has fast access port access for CPU1 and CPU2 program and data access while CDAx RAM has fast port access for CPU1 and CPU3 program and data access.
Program access from other CPUs is not supported. For example, CPU3 does not have program access for LDAx RAM. Fast access ports support 64-bit program access, and the program access bridge connects the 64-bit memory interface to the 128-bit memory bus of the CPU. The accesses between the program access bridge and the 64-bit memory controller are zero wait states, but the bridge initiates two accesses to form a 128-bit word. This is effectively one wait state for a 128-bit word with respect to CPU. The CPUa and CPUb data write access ports have one level of buffering, and the write buffer also handles read-modify-write operations.
The following is the round-robin priority order:
Other details regarding the 64-bit memory controller are the same as the 128-bit memory controller, with the only difference being the width of the memory controller. Refer to Section 3.10.4.3.1 for more information.