I am doing component selection for a new project, which is going to be an upgrade to a current project.

The original project involved an ATmega32U4 which handled USB mass storage using LUFA and also used FatFs for internal data logging to a microSD card. This project used around 26 out of 28KB (4KB was occupied by a bootloader) of flash memory and around 88% of the available 2.5KB of SRAM on the ATmega32U4

The LPC11U24 has 32KB of flash memory and 8KB of RAM. I know that this particular microcontroller has USB code stored in ROM to save space, also that this is a 32 bit MCU vs 8 bit, but exactly how much extra room can I expect to save?

If I compile a program for the LPC1768 using USB mass storage to see the flash utilization, how many bytes would the ROM on the LPC11U24 save? If I wanted to check myself, I can only do it through my LPC1768 mbed since I do not have permission to compile for the LPC11U24 yet. I would like to see some statistics about the instruction set sizes and such before making the investment.

if you are going for a bear metal design, don't forget you will loose the magic chip's extera functionality.

and also I believe there is only ONE EACH OF..

Serial. SPI, I2C

but you should be able to get USB Serial.

Ceri

FYI,

There is a memory usage comparison about a famous elm-chan's FatFs module.

http://elm-chan.org/fsw/ff/en/appnote.html#memory

It looks Cortex-M3 is more efficient than AVR.