I have always wondered kind of bandwidth you could make by multiple channels of PSRAM driven by PIO/DMA. Individually they're not so speedy(although the APS6408L-OCH-BA seems pretty crazy) , but how many can you run simultaneously. In terms of the RP2350 it would be fascinating to see how many times a second could you replace the entire contents of SRAM.
PSRAM is a possibility that I have explored for offloading the delay line buffers, which occupy quite a significant chunk of SRAM at the moment. It should be fast enough.
Default specs matter a lot for worldwide availability and affordability, as well as for the willingness of people to spend a lot of time creating free software for it.
520KB of SRAM is actually on the high end for microcontrollers. It doesn't seem like much but SRAM is on-die and significantly lower density than DRAM. For comparison, it's the same type of memory used for CPU caches, which are also small!
You can easily find dev boards with 8MB of PSRAM online if you need it. Or you can buy the PSRAM and hook it up yourself. If you still need more memory than that then you're looking at the wrong chip for the job.
I have always wondered kind of bandwidth you could make by multiple channels of PSRAM driven by PIO/DMA. Individually they're not so speedy(although the APS6408L-OCH-BA seems pretty crazy) , but how many can you run simultaneously. In terms of the RP2350 it would be fascinating to see how many times a second could you replace the entire contents of SRAM.
Can surely get more bandwidth but the it's less useful because it will not be directly accessible by the CPU anymore.
I believe PSRAM is directly accessible by CPU (there is even cache for PSRAM). Or am I missing something?
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PSRAM is a possibility that I have explored for offloading the delay line buffers, which occupy quite a significant chunk of SRAM at the moment. It should be fast enough.
Default specs matter a lot for worldwide availability and affordability, as well as for the willingness of people to spend a lot of time creating free software for it.
520KB of SRAM is actually on the high end for microcontrollers. It doesn't seem like much but SRAM is on-die and significantly lower density than DRAM. For comparison, it's the same type of memory used for CPU caches, which are also small!
You can easily find dev boards with 8MB of PSRAM online if you need it. Or you can buy the PSRAM and hook it up yourself. If you still need more memory than that then you're looking at the wrong chip for the job.
I shouldn’t wish for more onboard RAM for the next Pico iteration because other boards already have more. Okay, dude.
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