Hard fault after enabling interrupts in loaded application

franti_ekkaftan — Sat, 22 Aug 2015 13:05:18 GMT

Hi all,

I am writing a custom bootloader for the FRDM-K64F.

Up to now I've solved all problems, the loader is running fine and flashing the application OK (flash image correct, CRC for app correct etc.).

So it is almost finished but the last step seems to be always the hardest, as we are stuck on this last issue:

When jumping to application Hard fault is called after first interrupt is called.

All the interrupt stuff seems to be correct (application vector table is on correct place, all vectors initialized, SCB-VTOR pointing correctly, only FLASH vector table used).

This is the stack trace from KDS, running bootloader which just called the downloaded application:

freescale_k64f_Debug_OpenOCD [GDB OpenOCD Debugging]

freescale_k64f_bootloader.elf

Thread #1 (Suspended : Step)

0x10172

<signal handler called>() at 0xfffffff1

<signal handler called>() at 0xfffffff9

0x1085e

__isr_vector() at 0x100

openocd

arm-none-eabi-gdb

The exception comes when the first interrupt comes, after "cpsie i" instruction is called in the application.

The source of the interrupt should be the low power timer, which is configured in the application, and the IABR register corresponds with it:

IABR uint32_t [8] 0xe000e300

IABR[0] uint32_t 0x0

IABR[1] uint32_t 0x4000000

IABR[2] uint32_t 0x0

IABR[3] uint32_t 0x0

IABR[4] uint32_t 0x0

IABR[5] uint32_t 0x0

IABR[6] uint32_t 0x0

IABR[7] uint32_t 0x0

Core registers at entering the hard fault handler:

General Registers General Purpose and FPU Register Group

r0 0x400ff100

r1 0x4000000

r2 0x0

r3 0x41a

r4 0x0

r5 0x0

r6 0x0

r7 0x2002fff8

r8 0x0

r9 0x0

r10 0x20020000

r11 0x0

r12 0x100

sp 0x2002ffb8

lr 0xfffffff1

pc 0x10170

xPSR 0x1000003

msp 0x2002ffb8

psp 0x0

primask 0x0

basepri 0x0

faultmask 0x0

control 0x0

When interrupts stay disabled in the application then the application runs normally (except for the interrupt-related stuff).

EDIT: This is the SCB register block:

SCB SCB_Type * 0xe000ed00

CPUID const volatile uint32_t 0x410fc241

ICSR volatile uint32_t 0x44a003

VTOR volatile uint32_t 0xc100

AIRCR volatile uint32_t 0xfa050000

SCR volatile uint32_t 0x0

CCR volatile uint32_t 0x200

SHP uint8_t [12] 0xe000ed18

SHCSR volatile uint32_t 0x0

CFSR volatile uint32_t 0x20000

HFSR volatile uint32_t 0x40000000

DFSR volatile uint32_t 0x0

MMFAR volatile uint32_t 0xe000edf8

BFAR volatile uint32_t 0xe000edf8

AFSR volatile uint32_t 0x0

PFR const uint32_t [2] 0xe000ed40

DFR const volatile uint32_t 0x100000

ADR const volatile uint32_t 0x0

MMFR const uint32_t [4] 0xe000ed50

ISAR const uint32_t [5] 0xe000ed60

RESERVED0 uint32_t [5] 0xe000ed74

CPACR volatile uint32_t 0xf00000

Seems that it is the INVSTATE bit is set in CFSR and FORCED bit is set in HFSR, which means an escalated fault. But what is the cause I don't know.

Thank you for any help

Re: Hard fault after enabling interrupts in loaded application

franti_ekkaftan — Mon, 24 Aug 2015 08:30:46 GMT

Finally I have found the problem.

It was the VTOR register which has to be aligned to 0x400 for K64F.

Moving VTOR from 0xC100 to 0xC000 or 0xC400 solved the problem.

Re: Hard fault after enabling interrupts in loaded application

ganeshramachand — Tue, 26 Apr 2016 09:45:15 GMT

Dear Frank,

Even I face the same problem [ <signal handler called> () at 0xfffffff9 ] while debugging my custom boot loader code for KE02Z controller. I am using Segger's J link debugger and working on KDS2.0. What should I do to fix the error ?

Thanks

Re: Hard fault after enabling interrupts in loaded application

Oxolotol — Wed, 21 Feb 2024 23:16:59 GMT

I am having a similiar problem. But my VTOR is set to 0x00003000. and reads as 0x00003000 in the Memory Browser.

Originally it was set to 0x00003080, which the Memory Browser displayed as 0x00003000 and but with the 1 bit displayed several bytes away.

but moving it to even x000 (4k) boundary did fix *not* the '<signal handler called>() at 0xfffffff9. which resulted in the HardFault after CTIMER interrupts.

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Hard fault after enabling interrupts in loaded application

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