PSRAM for BLE stack

[darshan-mirajkar]

Can we use PSRAM for BLE stack?? If yes what are the changes required?

[h2zero]

I think this is possible, I have not tested.

You would need to change this line in nimconfig.h to CONFIG_BT_NIMBLE_MEM_ALLOC_MODE_EXTERNAL.

Let me know if that works.

[darshan-mirajkar]

Sure... I am looking for module with PSRAM...I'll let you know

[ntwallace]

@h2zero changing that line results in:

lib/NimBLE/src/port/src/esp_nimble_mem.c:31:47: error: #elif with no expression
lib/NimBLE/src/port/src/esp_nimble_mem.c: In function 'nimble_platform_mem_calloc':
lib/NimBLE/src/port/src/esp_nimble_mem.c:44:47: error: #elif with no expression
*** [.pio/build/esp-wrover-kit/lib839/NimBLE/port/src/esp_nimble_mem.c.o] Error 1

It looks like in esp_nimble_mem.c all the #elifs are missing a defined. Adding that fixes the problem and the stack loads in PSRAM, e.g.:

#ifdef CONFIG_BT_NIMBLE_MEM_ALLOC_MODE_INTERNAL
    return heap_caps_malloc(size, MALLOC_CAP_INTERNAL|MALLOC_CAP_8BIT);
#elif defined CONFIG_BT_NIMBLE_MEM_ALLOC_MODE_EXTERNAL
    return heap_caps_malloc(size, MALLOC_CAP_SPIRAM|MALLOC_CAP_8BIT);
#elif defined CONFIG_BT_NIMBLE_MEM_ALLOC_MODE_IRAM_8BIT
    return heap_caps_malloc_prefer(size, 2, MALLOC_CAP_INTERNAL|MALLOC_CAP_IRAM_8BIT, MALLOC_CAP_INTERNAL|MALLOC_CAP_8BIT);

[h2zero]

@ntwallace Thanks for reporting this. Please consider raising the issue in esp-idf as that file is tracked from there. In the meantime I will consider fixing it here for this library's purposes.

[h2zero]

After looking at this again I think the fix is actually to define a value of 1 to the config define, such as:

#define CONFIG_BT_NIMBLE_MEM_ALLOC_MODE_EXTERNAL 1

I will add this line, commented, in nimconfig.

[ntwallace]

Ah good catch, makes sense. Thanks.

[darshan-mirajkar]

Nice one guys... I am also looking for hardware with PSRAM to test this.

[ntwallace]

@darshan-mirajkar Mouser has the official Dev Kit C for $11 USD, looks like they have stock in most countries.

[darshan-mirajkar]

Yes I know... I our application hardware we designed PSRAM with the help of expressif. Gerber is ready... Waiting for PCB. So we. Continue on that.

[h2zero]

Closing this as resolved.