Anyone have some insider knowledge or just plain rumours of what chances are for ST considering releasing a STM32H7 with larger RAM in the near future?
Like 3MB or larger, as some STM32U5’s have (I also just noticed some competitors having large RAM devices, like i.MX RT533 / RT555 with 3MB and 5MB respectively)
The reason I ask is because this would make it possible placing two full-size frame buffers in internal RAM for displays with larger resolutions, doing away with the need for an external SDRAM.
The SDRAM makes PCB layout quite more complicated and needs more layers. It also requires a larger pin count device for the SDRAM connections, often making use of a BGA package necessary.
If only internal RAM is used a smaller pin count LQFP package can be used, making PCB layout much easier. The internal RAM is also much speedier than SDRAM, which is helpful for graphic applications with large and high FPS animations.
The STM32U5’s with 3MB is great for many graphic applications, but is possibly a bit underpowered at 160MHz for some applications with larger screen resolution or demanding animations.
Using two full-size frame buffers (double buffering) helps avoid tearing effects, but requires a lot of RAM. A 5” display with 800x480 resolution, and 24bit (RGB888) color depth, requires 2x800x480x24bit = 2.2MB for two frame buffers. A 7” 1024x600 display requires 3.5MB.
And then there must be memory left for the remaining tasks (perhaps 500kB or even 1MB, but I’m new to all things display related so am just guessing). If the goal would be to support resolutions up to say 1024x600 (which I guess covers a lot of display territory), then about 4.5MB is needed.
Well, just wanted to show my wish list for next years devices.
-Pete
