Re: Can I use MPLAB-X to view the internal SDRAM 32MB memory (for the PIC32MZ1025DAG169)
The PIC32MZ1025DAG169 internal 32MB DDR2 SDRAM works fine. There are many graphics demo projects in Harmony that use this part with the SDRAM. The newer PIC32MZ1025DAR169 just fixes many of the errata on the DAG family of parts. Some compatibility issues forced them to release the new parts with new part numbers. So for a new project it is recommended to use the new part. But the old part does work. You can compare the 2 errata docs on their web site to see what was fixed.
What version of MPLAB X IDE are you using? I know that at least version 4.20 and later have a Target Memory View Window for External DDR Memory. It shows data beginning at DDR2 SDRAM Physical address of 0x80000000. However, it is not clear to me if or how this data gets updated when the debugger halts. I suspect that 32MB is way too much to load every time the debugger halts. You may have to click the "Read Device Memory" button in the window to refresh it when you need to see it.
Note: although the PIC32MZ1025DAG169 datasheet shows it has "internal" 32MB DDR2 SDRAM, it is actually a stacked die so is technically external to the PIC32MZ die. Just wanted to clarify due to the conflicting usage above of words internal vs. external.