Is there a clear, simple explanation of how to setup the gcc linker scripts?

RE: Is there a clear, simple explanation of how to setup the gcc linker scripts?

Hein — Sun, 04 Feb 2018 20:38:02 GMT

Just a little trap to watch out for, the soft device size changes between versions, so linker scripts have to be changed if you change soft device version.

RE: Is there a clear, simple explanation of how to setup the gcc linker scripts?

Mron — Sun, 04 Feb 2018 00:08:21 GMT

"ORIGIN = 0x1b000, LENGTH = 0x40000 - 0x1b000" is more understandable. As my elementary school teacher would say- "Show your work".

This is the info I needed: "Softdevice RAM usage depends on how many features you enable. See documentation for sd_ble_enable() function call."

Thanks

RE: Is there a clear, simple explanation of how to setup the gcc linker scripts?

Turbo J — Sat, 03 Feb 2018 21:21:48 GMT

Elementary Math: 0x40000 - 0x1b000 = 0x25000

Softdevice RAM usage depends on how many features you enable. See documentation for sd_ble_enable() function call.

RE: Is there a clear, simple explanation of how to setup the gcc linker scripts?

Mron — Sat, 03 Feb 2018 19:22:53 GMT

Thanks for your reply. i have found many .ld scripts to look at., Very few are well documented. I've had trouble getting examples to run, and several times it's because I picked the wrong .ld. Having one or two well documented examples would help me understand what i'm looking at when I open a .ld file. For instance few use .ld math. For instance:

FLASH (rx) : ORIGIN = 0x1b000, LENGTH = 0x40000 - 0x1b000 <- clearer to me
vs

FLASH (rx) : ORIGIN = 0x1b000, LENGTH = 0x25000 <- where did this number come from?

and .ld files for the same board and same soft device will have different values:

RAM (rwx) : ORIGIN = 0x20002bd8, LENGTH = 0x5428 <- sometimes it's this

RAM (rwx) : ORIGIN = 0x20001eb0, LENGTH = 0x6150 <- and sometimes this --- Why did this one need less RAM for the soft device ?

RE: Is there a clear, simple explanation of how to setup the gcc linker scripts?

Turbo J — Sat, 03 Feb 2018 18:11:35 GMT

There are a lot of them in the SDK examples, and they should work for most custom projects without any modifications.

RE: Is there a clear, simple explanation of how to setup the gcc linker scripts?

Mron — Sat, 03 Feb 2018 17:14:37 GMT

I've run down info on linker script syntax and function. I would like to know when and how to modify them.