Hi all,
I love the fact that the ESP32 supports SPI RAM. I understand that there are limitations to putting a lot of RAM on-die, so I appreciate the option of being able to implement external RAM.
However, I was surprised to see that the only chip that's supported is the PSRAM chip manufactured by Espressif. There are a lot of SPI RAM chips available on Digikey that only use a slightly different instruction set. Is it difficult to modify the code to support these chips?
I looked at the "PSRAM.c" code, but it's a bit over my head, and I suspect there may be some hardware functionality that's going on that I can't see...(the file looks too small to implement all functionality). So I'm wondering, what's the limiting factor to supporting other types of external SPI SRAM chips?
Thanks!
Casey
SPI RAM - Support for other chips
Re: SPI RAM - Support for other chips
I couldn't find any SPI RAM chip available on DigiKey, could you give a link to any.caseymdk wrote:Hi all,
I love the fact that the ESP32 supports SPI RAM. I understand that there are limitations to putting a lot of RAM on-die, so I appreciate the option of being able to implement external RAM.
However, I was surprised to see that the only chip that's supported is the PSRAM chip manufactured by Espressif. There are a lot of SPI RAM chips available on Digikey that only use a slightly different instruction set. Is it difficult to modify the code to support these chips?
I looked at the "PSRAM.c" code, but it's a bit over my head, and I suspect there may be some hardware functionality that's going on that I can't see...(the file looks too small to implement all functionality). So I'm wondering, what's the limiting factor to supporting other types of external SPI SRAM chips?
Thanks!
Casey
Except Espressif SPIRAM, Lyontek's psRAM chips also works with ESP32.
I have also tested IPUS IPS6404 SPIRAM (the 3.3V version available at Electrodragon and it works without issues.
Re: SPI RAM - Support for other chips
And max size 128 KB + max clock 20 MHz, quite unusable as ESP32 external RAM.
Re: SPI RAM - Support for other chips
Yes, but even more unusable is the lack of the ESP-PSRAM chip from distributors...I would much rather use a different, 128KB chip than nothing.loboris wrote: And max size 128 KB + max clock 20 MHz, quite unusable as ESP32 external RAM.
Is the 20MHz a deal-breaker? Looks like the ESP32 runs external RAM at 40MHz by default...could this be decreased to 20MHz?
Re: SPI RAM - Support for other chips
Did you try to buy direct from espressif?caseymdk wrote: Yes, but even more unusable is the lack of the ESP-PSRAM chip from distributors.
Re: SPI RAM - Support for other chips
I have not, I'm not at a point where I can buy large volumes, which I assume I'd need to in order to get it direct.
Re: SPI RAM - Support for other chips
Usually the first 2 sample orders have no volume requirements. Especially if the part is not available through distribution I think they will be more accommodating.
Re: SPI RAM - Support for other chips
Hi loboris,loboris wrote:
Except Espressif SPIRAM, Lyontek's psRAM chips also works with ESP32.
I have also tested IPUS IPS6404 SPIRAM (the 3.3V version available at Electrodragon and it works without issues.
I also add more Rams for ESP32 Wroom 32D by using IPUS IPS6404, what you recommend.
But it doesn't work.
Do you have to modify anything in code ?
Of cousre, I connect it following reference design of ESp32 Wrover, which has 4Mb Psram External.
Can you help me?
Thanks.
Re: SPI RAM - Support for other chips
You just have to connect SPI-RAM chip to the right pins and use one 10K pull-up on CS pin.mrbhou wrote:Hi loboris,
I also add more Rams for ESP32 Wroom 32D by using IPUS IPS6404, what you recommend.
But it doesn't work.
Do you have to modify anything in code ?
Of cousre, I connect it following reference design of ESp32 Wrover, which has 4Mb Psram External.
Can you help me?
Thanks.
You can check my post here.
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