MCUXpresso IDEのトピックUSB RAM use

USB RAM use

CCandido — Wed, 03 Jan 2018 12:03:46 GMT

Hi,

library usb Virtual Com Port, use 17K RAM.

question 1:

there is a way to decrease the ram size used ?

type const in flash.

question 2:

how to switch CDC, with request to send or without.

or, how to automatic ECHO request to send MCU.

my code ever send Frame (resquest to send).

cdc without uart.

thanks,

Carlos.

Re: USB RAM use

lpcxpresso_supp — Thu, 04 Jan 2018 11:08:15 GMT

Hi Carlos,

The data portion of RAM usage will consist of various elements including heap, stack, variables, buffers etc. The allocation sizes for the heap and the stack may be candidates for reduction:

The MCUXpresso IDE User Guide chapter 'Memory Configuration and Linker Scripts' covers this are is some detail - in particular see 'More advanced heap/stack placement'.

The requirement for buffer space within a USB project will typically be chosen based on some performance requirement. You would have to perform some local testing to see what penalties might be seen if these were reduced.

Questions relating to specific SDK projects should be raised in the SDK forum - where the SDK, MCU, board and project name should be given.

Yours,

MCUXpresso Support

Re: USB RAM use

CCandido — Thu, 04 Jan 2018 12:50:33 GMT

Hi Support,

I'll try to reduce this size.

thanks,

Carlos.