Embedded Design Handbook

ID 683689
Date 8/28/2023
Public
Document Table of Contents

7.5.4.2. Dual Port Memories

Each tightly coupled master connects to one tightly coupled slave over a tightly coupled interface. For this reason, it is helpful to use dual port memories with the tightly coupled instruction master as shown in Figure 280. The tightly coupled instruction master is incapable of performing writes because it accesses code for execution only. Without a second memory port connected to an Avalon® Memory-Mapped ( Avalon® -MM) data master, the system does not have write access to the tightly coupled instruction memory. Without write access, code cannot be downloaded into the tightly coupled memory by the Nios® II SBT for Eclipse, which makes development and debugging difficult. Without a second port on the tightly coupled instruction memory, no data master has access to the memory, which means you have no way to view the contents. By making the tightly coupled instruction memory dual port, the embedded processor’s data master can be connected to the second port, allowing both reading and writing of data.