LPC Microcontrollers中的主题 Re: LPC812: Code size too large

LPC812: Code size too large

fjrg76 — Tue, 21 Jun 2016 04:16:17 GMT

Hi, while working with the LPCXpresso 812MAX I observed that the code produced for the blinky project is 5532 bytes, too mucho for such a small project (with no optimization at all), but the Board and Chip libraries are set to -Os because no one is going to debug any of them. Is that figure normal for that project?

Re: LPC812: Code size too large

jeremyzhou — Wed, 27 Jul 2016 03:26:47 GMT

Hi,

Regarding to the statement above, the image file is contained many object files which definitely increase its size.

You shall remove the corresponding head files in the chip.h, it can reduce the size by through the approach.

Have a great day,
Ping

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Re: LPC812: Code size too large

avt — Wed, 27 Jul 2016 08:51:50 GMT

The point of the examples is not to produce the smallest possible example, but to show you how to use the chip, and the LPCOpen libs and to do it in an understandable way. The libraries include code that is not strictly needed by a blinky, but will be used in a more practical application.

If you want to find a small blinky, search these forums - I seem to remember a 'competition' a couple of years ago, that had the blinky down to a hundred bytes or so.

Re: LPC812: Code size too large

avt — Wed, 27 Jul 2016 08:54:26 GMT

Here is the thread for a minimal blinky:

https://community.nxp.com/message/772566#comment-772566

Re: LPC812: Code size too large

lpcxpresso_supp — Wed, 27 Jul 2016 19:16:25 GMT

By default, most LPCOpen provided examples build against the "Redlib (Nohost)" variant of the C library - which is needed if the code is doing a printf, but is otherwise not needed. Try switching the C library being linked against to "Redlib (None)".

Switching the selected C library

This will typically reduce flash/ram requirements noticeably.

I would also suggest reading:

Application Flash / RAM size

Looking at the map file should give you a good idea of what is actually being pulled into your linked image.

Regards,

LPCXpresso Support

Re: LPC812: Code size too large

rianzu — Thu, 04 Aug 2016 06:38:25 GMT

1. Look into your *.map file and see exactly what symbols occupies .text and how big they are.

2. Link with NewLib (nano) and don't use float options.

3. Use -Os for entire project but with care (force some drivers with -O0)

Original drivers are buggy and linking with -Os sometimes will provide unexpected results. Also some of them are completely un-optimized for small embedded so indeed, will produce a lot of code, consuming both PGM and performances.