external ram

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koendv
Posts: 3
Joined: Wed Oct 28, 2020 12:50 pm

external ram

Postby koendv » Wed Oct 28, 2020 1:21 pm

I've been wondering about ways to increase available memory without increasing price too much. Here's my proposal: an external 8mb spi ram, and a micropython module to access an this spi ram. You can buy these rams for around $1.

https://github.com/koendv/micropython-psram

Storing objects in external ram becomes interesting when the object is large. What I'm wondering about is the following: what do you think about modifying ulab so large arrays are stored in external ram? When you access the array, the array is copied to internal ram. When memory runs out and garbage collection is called, the least recently used array is written back to external memory and internal ram is freed. Or do you have another suggestion?
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kwagyeman
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Joined: Sun May 24, 2015 2:10 pm

Re: external ram

Postby kwagyeman » Wed Oct 28, 2020 2:05 pm

32-bit SDRAM can be bought for like $1. However, the volume just needs to be high. SPI based SRAM is interesting, but, very slow. If you want to support it on a custom fork that is fine. However, it would be a lot of work for not much gain for us.
Nyamekye,
koendv
Posts: 3
Joined: Wed Oct 28, 2020 12:50 pm

Re: external ram

Postby koendv » Wed Oct 28, 2020 2:25 pm

If I may make a suggestion: on the successor to the H7, put a footprint for a SPI RAM on the back of the pcb. An empty footprint does not cost anything.
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kwagyeman
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Joined: Sun May 24, 2015 2:10 pm

Re: external ram

Postby kwagyeman » Wed Oct 28, 2020 3:01 pm

:) The successor will have HyperBus RAM. Standard. But, a new variant with more bandwidth and storage.
Nyamekye,

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