[sdiy] external memory for microcontrollers

[Veronica Merryfield]

> I've been using STM32, especially the F3 series that tops out around 32k. The part I'm really digging on (STM32F334) has 12k only. I've played with the 23LC1024 SPI SRAM chips, and it seems like they're fast enough with dual or quad SPI (and maybe just barely fast enough with regular SPI @ 18Mbits/sec). They cost about as much as the micro itself, though, which isn't quite cool, and I'd really need a few. I know some of the ST parts have the "FSMC" memory controller for SDRAM etc, and maybe that's the way to go here. not worried about the storage being non-volatile, I just want more ram to play with. I'm seeing some ~$50 looper pedals from not-too-huge manufacturers with over 5 minutes of time, so I figure this must be reasonably affordable. 
> 
> anyone have better ideas or experience here? 

I have done a delay pedal design for a company using SPI memory. It worked ok and sells but lots of compromises.

Those not so expensive loopers are not using particularly high fidelity sound so they can cut the storage requirement and speed needed to make it work for a low BOM cost.

If you really want a decent rate and decent amount of memory without needing to auction your first born, you’ll have to bite the DDR bullet and find a micro that can manage it - not sure what your budget is, but there are solutions in the $10 to $15 if you look in the right places that will give you an ARM, DDR plus the usual clutch of peripherals etc.

Veronica