Transferring the project to nRF52811 hardware - FPU error

[Ricardo N]

Hello,
I am using the PCA10056 to program a nrf52811 chip on a custom board with SDK 15.3.0.
I'm using the example ble_app_blinky_pca10056_s140
I am following the steps in Infocenter infocenter.nordicsemi

Although I'm having questions on 2 points

1. I get a compilation error "#error "Compiler generates FPU instructions for a device without an FPU (check __FPU_PRESENT)""
in 
#elif defined ( __GNUC__ )
  #if defined (__VFP_FP__) && !defined(__SOFTFP__)
    #if (__FPU_PRESENT == 1U)
      #define __FPU_USED 1U
  #else
    #error "Compiler generates FPU instructions for a device without an FPU (check __FPU_PRESENT)"
    #define __FPU_USED 0U

I checked and __FPU_PRESENT is set to 1

2. On step 6 in the documentation I can't find the files to delete, _startup_nrf52.s and system_nrf52.c


I would really appreciate if I can get some help

[awneil]

https://devzone.nordicsemi.com/f/nordic-q-a/20825/fatal-error-pe035-error-directive-compiler-generates-fpu-instructions-for-a-device-without-an-fpu-check-__fpu_present

https://devzone.nordicsemi.com/f/nordic-q-a/47627/running-ble_app_uart_c-on-a-nrf-52810-error-compiler-generates-fpu-instructions-for-a-device-without-an-fpu-check-__fpu_present

https://devzone.nordicsemi.com/f/nordic-q-a/24357/compiler-generates-fpu-instructions-for-a-device-without-an-fpu

[Ricardo N]

Hi I accidentally verified answer but it is not solved yet
Thank you for the reply
I already tried the first solution, and the third doesn't seem to apply
The second seems interesting but I'm unsure if the changes for nrf52810 are the same as for nrf52811

There is one thing that I suspect. I didn't adjust the RAM and flash sizes as it is in the description

• ROM END: 0x2FFFF
• RAM END: 0x20005FFF

Which macros in specific should I change?

[awneil]

Ricardo N said:

unsure if the changes for nrf52810 are the same as for nrf52811

As far as not having an FPU, that would be the same.

Memory sizes wouldn't have anything to do with it complaining about FPU instructions.

[Ricardo N]

Yes you are right about the memory sizes

but nrf52811 has a Cortex-M4 processor and that processor has FPU if I'm right
The problem must be elsewhere

[awneil]

Ricardo N said:

Cortex-M4 ... has FPU

No - FPU is optional with Cortex-M4

Sometimes, people say Cortex-M4F to identify that the FPU option is fitted.

[awneil]

See the 'CPU and support module configuration' Table in the Product Spec:

https://infocenter.nordicsemi.com/topic/ps_nrf52811/cpu.html?cp=3_2_0_3_0_1#reference_ns1_fkb_2r

[Ricardo N]

Thank you very much for pointing me to this table!
So I need to find a way to not use FPU. Is there an alternative? like a soft floating point?
I tried to disable FPU by defining the macro NO_FPU_ENABLE but it still doesn't work

[awneil]

Again, in this respect, it will be the same as the nRF52810:

https://devzone.nordicsemi.com/f/nordic-q-a/33812/developing-for-nrf52810---the-full-story