Most recent, fully functional, GCC example code?

[chalecampb]

Hi,

I am trying to get even a basic ARM GCC example set up using the provided toolchain code, and am having a rough go at it.

First, what is the most recent, working, full example of how to set up ARM GCC to compile and deploy to a nRF51 DK? I have no 'difficult' goals - I am running without a softdevice, with only GPIO, no standard library, not trying to implement OTA firmware or anything. I can figure out Eclipse later, I just need to be able to deploy to a target for now.

My procedure was this -

1. Changed the $sdk/components/toolchain/gcc/Makefile.posix to point to /usr/local, where the ARM GCC is linked
2. CD to the blinky armgcc directory, make, make flash
3. The .hex is around 3kB, which is what we would expect for a gpio-only hex file
4. Worth pointing out at this point that "make flash" is broken, it calls --program when my nrfjprog uses --flash for some reason. Even then, as written, it calls flash on _build/.hex, which is obviously wrong. So, I do it manually, with JLinkExe commands r, loadfile _build/nrf51422_xxac.hex, r, g in a script file.
5. In any case, it says that it flashes successfully, but the expected pins are not toggling.
6. If I use JLinkExe and halt it just says that PC is at 00000. After stepping, CycleCnt doesn't change, PC doesn't change, etc. IPSR says HardFault - maybe a problem with the startup code?
7. Speaking of which, I read that some people saw blinky start at _start, which is a stdlib function, and suggested that blinky would work with the CFLAG -nostdlib. This didn't change anything.

When I halt, I see the following output -

PC = FFFFFFFE, CycleCnt = 00000000
R0 = FFFFFFFF, R1 = FFFFFFFF, R2 = FFFFFFFF, R3 = FFFFFFFF
R4 = FFFFFFFF, R5 = FFFFFFFF, R6 = FFFFFFFF, R7 = FFFFFFFF
R8 = FFFFFFFF, R9 = FFFFFFFF, R10= FFFFFFFF, R11= FFFFFFFF
R12= FFFFFFFF
SP(R13)= FFFFFFD8, MSP= FFFFFFD8, PSP= FFFFFFFC, R14(LR) = FFFFFFF9
XPSR = 81000003: APSR = Nzcvq, EPSR = 01000000, IPSR = 003 (HardFault)
CFBP = 00000000, CONTROL = 00, FAULTMASK = 00, BASEPRI = 00, PRIMASK = 00

The obvious questions,

• What am I missing to make this work?

• Is there a way to step through the code, on the command line? I will look up GDB in the meantime.

• From an organizational perspective, are there Makefile examples that are self-contained? The current system looks like it would work best if you duplicated the example projects in-place. There doesn't seem to be a way for me to just "point to" a nRF SDK installation and have it use the files there, without modifying the Makefile. I did that, and got the same result, so it's not hard, but I am interested to know why this method of organization was selected. It seems a little awkward to have to actually drop your code into the nRF SDK examples folder to use the provided stationary.

Version notes -

OSX Yosemite, 10.10.2
ARM GCC version 4.7.4 20140401 (release) [ARM/embedded-4_7-branch revision 209195]
SDK 8.0.0

Thanks,

-Alex

[Nguyen Hoan Hoang]

When the chip has Softdevice flashed in, it won't work directly due to protection. You need to do full erase before you can debug any program that does not use Softdevice.

[Nguyen Hoan Hoang]

That is what I meant. not using Softdevice. The problem you are having is very similar to the problem I mentioned. When you run a Blink Blank on a blank chip, it's fine. If you run the Blinky blank on a chip already have Softdevice burned in. The jtag is unable to write you blinky lot location zero but it thinks that the write was successful and crash with register dump all FF. This problem is not only with Jlink but also with OpenOCD. After using nRFGo to perform an erase all, blinky blank works.