Jedidiah oyeyemi

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10 years, 1 month ago.

How much Ram do u actually have?

im new to this and i say there is a build option that tells me the ram and flash usage of my program but according to that im gonna be going over the 32k ram limit but on wikipedia i read that this had something along 80k of ram?

Question relating to:

Last updated: 20 Apr 2021
Affordable and flexible platform to ease prototyping using a STM32F401RET6 microcontroller.

2 Answers

Stephen Paulger
10 years, 1 month ago.

The Nucleo F401RE has 96KB of SRAM (datasheet).

What is telling you there is a 32KB limit?

Accepted Answer

/media/uploads/jeddaboy/memory_usage.png I bought this controller because i needed lots of ram to store samples. then i saw the buld window but these are the results from that window

posted by Jedidiah oyeyemi 07 Mar 2014

and thanks it seems the program still runs when i put the giant array in it as long as i don't exceed that 96k

posted by Jedidiah oyeyemi 07 Mar 2014

Right, that is a bug in our data about the F401RE, I'll make sure that gets sorted out. Thanks for letting us know.

posted by Stephen Paulger 07 Mar 2014
Paul Staron
10 years, 1 month ago.

I have a similar issue with the LPC1768 that is very strange, I'm up to 508%, 162.6k Ram on the build info. No big arrays, but several font files that I assume would reside in flash anyway. Program works as it should so I have kept going. Any suggestions?

Code is a bit big to show here, however I'm using the Mini-DK libraries to drive a touch screen display and that's when I noticed this. The same code using a serial touch display is on the left. I will start a new program using the same libraries and see if I can find the point where it starts to exceed the limit.

/media/uploads/star297/lpc1768.jpg

Just checked this code out and get the same result. so must be something in the Mini-DK lib's here

http://mbed.org/users/frankvnk/code/Mini-DK/

Masive Ram use

#include "mbed.h"
#include "Mini_DK.h"

    SPI_TFT TFT(p5, p6, p7, p8,"TFT");  // TFT -> mosi, miso, sclk, cs
    TouchScreenADS7843 TP(p11 ,p12 ,p13 ,p15 ,p14, &TFT);  // ADS7843 -> mosi, miso, sclk, cs, irq, SPI_TFT
    
   
int main()  
{      
  
  while(1){}
  
}

Can you share a program with us so we can look at it? Or a screenshot like Jedidiah shared in the post above.

posted by Martin Kojtal 07 Mar 2014

Mini-DK library reserves flash memory which can be used to store a background image for the TFT using in-application programming. (Alot faster to write than all other options). However the method it is reserved in the IAP library confuses the compiler so it think it is also RAM memory. Only affects the compiler output window though.

posted by Erik - 08 Mar 2014