build USB project, RAM using upto 50516byte, why?

[9218sky]

1. USB PROJECT:

    lpcopen_2_20\applications\lpc18xx_43xx\keil\keil_mcb_1857\lpcusblib_host\usbhost_msc\usbhost_msc 

    Program Size: Code=27928 RO-data=1692 RW-data=108 ZI-data=48716  

2. but build SDcard file system using RAM following:

    Program Size: Code=14770 RO-data=682 RW-data=48 ZI-data=6952  

how do lessen RAM using?

[chrispflieger]

Is optimization turned on? Try the -Os option.

[9218sky]

Hi, Chris

optimization select level-3, only code as lessen, but RAM no change!

[converse · Accepted solution]

Suggest you look in the linker map file to see what is using the space - I would guess it is used for buffers etc.

[9218sky]

Hi, Con Verse

look in map file, get RAM expend information.

because "keil_startup_lpc18xx_43xx.s" define head size:

"Heap_Size       EQU     0x00006000"

I set the value to 0Byte.

build and test as successful.

thanks.