maximum ram usable is 96000

[manecolooper]

maximum ram usable by my sketch is 96000 , i defined it as:

#define MAX_DELAY 96000
byte sDelayBuffer0[MAX_DELAY];

if i define more than that , error is

region `dram0_0_seg' overflowed by 24064 bytes ( i set MAX_DELAY to 128000)

compiler reports that there is more ram free, how can i use it?

Serial.println(ESP.getFreeHeap());

returns 127336

i also tested malloc , new and dividing the memory needed into two segments, but crashes the same ( reset loop ) when sum of both segments exceed 96000

[beegee-tokyo]

I have no proof, but I guess that FreeRTOS reserves memory for other tasks and temporary variables and doesn't allow you to reserve all of the free RAM.

[manecolooper]

Is true, that's why of the 380 k of ram you have less than 300 left, but i can not go past 96000

[ZinggJM]

This used to work in an earlier version I had installed on 24.7.2017, fortunately I kept it on my development notebook, but on the updated version installed on my test notebook I now have this issue. I need big RAM for buffer for multiple big e-paper displays!

[manecolooper]

ZinggJM any solution to use it today? thanks!

[ZinggJM]

Someone should check if this issue also exists in esp-idf.
And Espressif might tell us if this is a parameter in some configuration file of the compiler.

[manecolooper]

ZinggJM thanks for your help, i wonder which size were you able to achieve in that versión of the compiler

[shirish47]

@ZinggJM Hi , I also once tested ESP32 with E-paper of older Kindle I think I was able to use around 800x500 px of 800x600 px .. but currently my problem is different I want to store accelerometer data in to array or buffers (xyz all 2 byte data ) and I am only able to store 9600 Samples(960032=57600 bytes ).

my code also has AWS IoT Wifi manager on it.
this is what arduino shows up.

Sketch uses 852426 bytes (65%) of program storage space. Maximum is 1310720 bytes.
Global variables use 105452 bytes (35%) of dynamic memory, leaving 189460 bytes for local variables. Maximum is 294912 bytes.

this means I have 65% ram(189460 bytes) left.
how could I use that 65% ? if I increase samples more than this 9600 It crashes.

[shirish47]

when is external RAM support be part of arduino core? or do we have it? what is the challenge for having SPI RAM in arduino core?

[stickbreaker]

@shirish47 Instead of one monolithic buffer try multiple buffers. Depending on your design, burst sampling or continuous upload, you may be able to process smaller buffers continuously.

Chuck.

[shirish47]

Ya At first the design was like one core picks the data puts in to 64 sample message and sends via queue to wifi (core 2) and publish over to AWS IoT .. but the queue size was limited to 100 such messages so after it was filled up we would have a blockage and then after like 2 seconds(sometimes 500milliseconds) it would resume but was also blocking the Core 1 that was getting 1600 samples rate data out of sensor. and that block would corrupt(delays between samples) ..we want continuous 30 seconds samples at 1600 rate.

[shirish47]

Also, can we use the SPI RAM on ESP Wrover-32 as SPI RAM for storage? like directly access it with SPI.h and just store data on to it. not like allocating memory from it.

[shirish47]

can someone test this?link I can't believe I can store so much data. I don't believe this. even esp32 does not have that much of RAM.
Please please please explain this. I am not sure what is this why this runs. and works

[shirish47]

https://esp32.com/viewtopic.php?f=19&t=5308

[atsteich]

can someone test this?link I can't believe I can store so much data. I don't believe this. even esp32 does not have that much of RAM.
Please please please explain this. I am not sure what is this why this runs. and works

@shirish47 The thing in your code is, that the data are never set to any value. Therefore the Compiler can do some optimization, and the ram for the array will never been allocated. As soon as u start filling the array with numbers you will get an compile error "region `dram0_0_seg' overflowed by 63501768 bytes". (You also need to do anything else with the numbers, e.g. printing them...)

[atsteich]

So is there still no solution found to the original problem? Why is the esp reporting a free Heap of (in my case) almost 200k, but still crashing? What would be the "correct" way to determine the left memory for variables? (For example if I want to buffer something as long as possible, but stop before crashing)..