LPC546xx Hardfault handling in the bootloader

terence_kong — Thu, 12 Dec 2019 21:29:26 GMT

Hi NXP,

I am trying to implement hardfault handling in the boot loader only.

I have a boot loader which will execute the main application after boot, and I want to implement the hardFault_Handler only in the boot loader. So when there is a hardfault error happened in the main application, it will jump to the boot loader and execute the HardFault_Handler in the boot loader.

However, when there is a hardfault happened in the main application, seems the program will be stuck in the main application and can never jump to the boot loader.

This is the HardFault Handler I put in the boot loader, it works fine if I put it in both the boot loader and main application.

It doesn't work if I replace the main application HardFault Handler with a function jump.

Does the boot loader and the main application have to have their own hardfault handler??

void HardFault_Handler(void)
{
#if(0)
__asm volatile
(
" tst lr, #4 \n"
" ite eq \n"
" mrseq r0, msp \n"
" mrsne r0, psp \n"
//Load the instruction that triggered had fault
" ldr r1, [r0, #24] \n"
" ldr r2, handler2_address_const \n"
" bx r2 \n"
" handler2_address_const: .word prvGetRegistersFromStack \n"
);
#endif
__asm( ".syntax unified\n"
// Check which stack is in use
"MOVS R0, #4 \n"
"MOV R1, LR \n"
"TST R0, R1 \n"
"BEQ _MSP \n"
"MRS R0, PSP \n"
"B _process \n"
"_MSP: \n"
"MRS R0, MSP \n"
// Load the instruction that triggered hard fault
"_process: \n"
"LDR R1,[R0,#24] \n"
"LDRH R2,[r1] \n"
// Semihosting instruction is "BKPT 0xAB" (0xBEAB)
"LDR R3,=0xBEAB \n"
"CMP R2,R3 \n"
"BEQ _semihost_return \n"
// Wasn't semihosting instruction so enter registers dump
//"B . \n" //enter inifinte loop
" ldr r2, handler2_address_const \n"
" bx r2 \n"
" handler2_address_const: .word prvGetRegistersFromStack \n"
// Was semihosting instruction, so adjust location to
// return to by 1 instruction (2 bytes), then exit function
"_semihost_return: \n"
"ADDS R1,#2 \n"
"STR R1,[R0,#24] \n"
// Set a return value from semihosting operation.
// 32 is slightly arbitrary, but appears to allow most
// C Library IO functions sitting on top of semihosting to
// continue to operate to some degree
"MOVS R1,#32 \n"
"STR R1,[ R0,#0 ] \n" // R0 is at location 0 on stack
// Return from hard fault handler to application
"BX LR \n"
".syntax divided\n") ;
}

Re: LPC546xx Hardfault handling in the bootloader

xiangjun_rong — Fri, 13 Dec 2019 05:37:23 GMT

Hi, Terence,

I think the HardFault is a general exception, you can run code in the ISR.

I see that you want to execute the bootloader code once the hardfault exception heppens, in the case, I suggest you reset the system by using the NVIC_SystemReset() function in CMSIS, which can set the SYSRESETREQ bit in NVIC->AIRCR register.

BTW, you can enable watchdog in the main() function, but in the void HardFault_Handler(void), do not feed the watchdog by disabling the Timer which feeds dog. In this way, the watchdog Reset will happen.

Hope it can help you

XiangJun Rong

Re: LPC546xx Hardfault handling in the bootloader

terence_kong — Fri, 13 Dec 2019 18:11:29 GMT

But after system reset, I won't be able to capture the HardFault information

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LPC546xx Hardfault handling in the bootloader

Re: LPC546xx Hardfault handling in the bootloader

Re: LPC546xx Hardfault handling in the bootloader