Why is printf not working with floating point on the STM32F407VG, IAR 8.30.1

[km shim]

ex) When compiled with IAR 8.30.1, HardFault exception was occured.

float gfSetDataRate = 100.0f;
printf("Data Rate = %f \r\n", gfSetDataRate);

HardFault is occured at VCVT.F64.F32 instruction.

I also tested following case

1. In case Compiled with GCC, is working well.
   1. Other device STM32F411, Working well with IAR, GCC.

What is wrong? IAR, my source, STM32F407 FPU?

Ggive me any other hints, please.

[AvaTar]

According to the ARM infocenter site (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0553a/CHDJAEDB.html), F64 is not a valid datatype for the M4 VCVT instruction.

[AvaTar]

You found it yourself in the meantime...

I would guess the offending instruction is legal in ARM mode (not thumb 2), or supported with double precision FPUs.

[km shim]

AvaTar​,

Thank you very much.