Renesas RX65 Envision Kit - part 12: RAM Use with GCC ToolChain

RE: Renesas RX65 Envision Kit - part 12: RAM Use with GCC ToolChain

DAB — Sat, 04 Jan 2020 18:46:55 GMT

It has been a long time since I did this level of detailed work in assembly language.

Memory mapping was very key in the old days as few of us had a fully populated memory space in which to do our software.

DAB

RE: Renesas RX65 Envision Kit - part 12: RAM Use with GCC ToolChain

Andrew J — Sat, 04 Jan 2020 10:26:22 GMT

For the LCD ram buffers, it’s worth bearing in mind that when using emWin, you will want two of these buffers (i.e. 2 x 261,120 bytes) to operate the screen without flickering, depending upon the frequency of changes to the screen your app makes. Without using multi-buffering, I found that the screen was not satisfactorily usable with emWin. See post 7 of my review. The alternative is to time the screen updates yourself based on vsync, something I didn’t try!

These are really useful follow up posts, thanks.

RE: Renesas RX65 Envision Kit - part 12: RAM Use with GCC ToolChain

clem57 — Fri, 03 Jan 2020 19:53:42 GMT

[mention:acaf6a9338de4eef8f6717d5561ed01d:e9ed411860ed4f2ba0265705b8793d05] Curious about code space versus SRAM space. On this processor are they different or the same? i.e. do they share the same bus or use unique bus for each. It seems the Max32650 and maybe the Max32660 use separate buses and therefore separate address space.

Clem

RE: Renesas RX65 Envision Kit - part 12: RAM Use with GCC ToolChain

Jan Cumps — Fri, 03 Jan 2020 19:01:14 GMT

Eclipse has a reasonable good map viewer too:

[View:/resized-image/__size/620x316/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-f316b0cb-0107-4fbf-8ac4-90527e401893/8132.contentimage_5F00_205595.png:620:316]

You can open it via Window -> Show View -> Other -> Memory usage.

It 'll load the map file of the currently active build configuration.

A particularly useful view is the areas of the hardware (it seems to know the full layout of the RM65N!), and how the program uses those:

[View:/resized-image/__size/621x538/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-f316b0cb-0107-4fbf-8ac4-90527e401893/5078.contentimage_5F00_205596.png:621:538]