FPU setup

ERussell — Wed, 19 Jun 2013 18:46:14 GMT

I am working with a K60FN1M processor and using CW10.4. I want to make sure that I am setting up the hardware FPU correctly. I have done the following:

1 - Selected Hardware vfpv4 in the Tool Settings under project properties.

2 - Selected c9x for the Library model

3 - Included the ewl c library

4 - Explicitly enabled the FPU by setting bits 10 and 11 in SCB_CPACR

5 - Set both the ASPEN and LSPEN in SCB_FPCCR to enable the extended exception frame and the lazy stacking options

6 - Added the suffix f to all float constants.

I am using a preemptive task scheduler rather than a full RTOS.

I want to be able to use library routines such as powf(), expf(), etc. and have them only use single precision float values. Is there a specific ewl library that I should specify or certain macros that need to be defined?

Thanks,

Elizabeth

Re: FPU setup

Hui_Ma — Wed, 03 Jul 2013 02:44:34 GMT

Hi,

There is no specific ewl library, you can use the system default one.

About enable the FPU, please check code for your reference:

; Enable the floating point coprocessor

#if defined (_VFPv4_)

MOVW r1,#60808 ; load CPACR

MOVT r1,#57344 ; (0xE000ED88)

LDR r0,[r1]

ORR.W r0,r0,#VFPEnable ; Enable FPU

STR r0, [r1] ; on CP10, CP11

MOV.W r0,#R2N_Enable

VMSR FPSCR, r0

#endif

Wish it helps.

topic FPU setup in Kinetis Microcontrollers

FPU setup

Re: FPU setup