Embedded Design Handbook

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

5.2.4.2. Nios® II Processor Application Executes In-Place from General Purpose QSPI Flash ( Intel® MAX® 10)

This is suitable for Nios® II processor applications that requires code space larger than the UFM ( Intel® MAX® 10 device only) and/or with a limited on-chip memory usage. This is an advantage for supporting larger or multiple software applications.

The alt_load () function operates as a mini boot copier that initializes and copies the writable memory sections only to OCRAM or external RAM. The code section (.text), which is a read-only section, remains in the QSPI flash memory region. Retaining the read-only section in QSPI minimizes RAM usage but may limit the code execution performance.

The Nios® II processor application is programmed into the general purpose QSPI flash. The Nios® II processor reset vector points to the general purpose QSPI flash to allow code execution after the system resets. If you are debugging the application using the source-level debugger, you must use a hardware break-point because the general purpose QSPI cannot support random memory access.

Figure 110. Nios II Application XIP from General Purpose QSPI flash (for Intel® MAX® 10)
Table 37.  RAM and ROM Size Requirement
RAM Size Requirement ROM Size Requirement
Equivalent to the dynamic memory space usage during run time which is the sum of the maximum heap and stack size. Executable code must not exceed the size of the QSPI flash.