Binary made by msp430-elf-g++ does not work when the BSS is too big.

Jongsoo Jeong

Prodigy 100 points

Other Parts Discussed in Thread: MSP430FR5969

Hi,

I don't know here is correct place to ask a question about msp430-elf-g++.

I also asked same question to https://sourceforge.net/p/mspgcc/mailman/mspgcc-users/, but there were no answers.

I’m a user of msp430-elf-g++.

I experienced a problem that binary made by msp430-elf-g++ does not work when its BSS is too big.

So I tested again by using sample code included in GCC package.

Here is my code.

blink.c

#include <msp430.h>
 
char buf[2945];
 
int main(void) {
    WDTCTL = WDTPW | WDTHOLD;               // Stop watchdog timer
    P4DIR |= 0x01;                          // Set P1.0 to output direction
 
    for(;;) {
        volatile unsigned int i;            // volatile to prevent optimization
 
if (buf)
  P4OUT ^= 0x01;                      // Toggle P1.0 using exclusive-OR
 
        i = 10000;                          // SW Delay
        do i--;
        while(i != 0);
    }
 
    return 0;
}

And here is my Makefile.

OBJECTS=blink.o
 
GCC_DIR =  ../../../bin
SUPPORT_FILE_DIRECTORY = ../../../include
 
DEVICE  = msp430f5438a
CC      = $(GCC_DIR)/msp430-elf-gcc
CXX     = $(GCC_DIR)/msp430-elf-g++
GDB     = $(GCC_DIR)/msp430-elf-gdb
OBJCOPY = $(GCC_DIR)/msp430-elf-objcopy
 
CFLAGS = -I $(SUPPORT_FILE_DIRECTORY) -mmcu=$(DEVICE) -O2 -g
CXXFLAGS = -I $(SUPPORT_FILE_DIRECTORY) -mmcu=$(DEVICE) -O2 -g
LFLAGS = -L $(SUPPORT_FILE_DIRECTORY) -Wl,-Map,$(DEVICE).map,--cref
 
all: ${OBJECTS}
$(CXX) $(CXXFLAGS) $? $(LFLAGS) -o $(DEVICE).out
$(OBJCOPY) -O ihex $(DEVICE).out $(DEVICE).hex
 
debug: all
$(GDB) $(DEVICE).out

Since I’m using TI TrxEB, I modified msp430fr5969 code for TrxEB to blink LED1 (P4.0).

When setting the buf size to 2944, it works. But when setting it size greater than 2944, the board freezes.

I also checked building same code using msp430-elf-gcc C compiler, and it works.

So I think C++ initialization part seems to have a problem.

I tested it on TI MSP430 GCC 4.0.0.900 beta version. I checked same problem exists on 3.5.0.0 version.

Please, help me.

Regards,

Jongsoo

over 9 years ago

0 Chester Gillon over 9 years ago

Guru 92251 points

Jongsoo Jeong said:
When setting the buf size to 2944, it works. But when setting it size greater than 2944, the board freezes.

The usual cause of such behaviour is that the a watchdog reset occurs during zero initialisation of the .bss section. The result is that the program doesn't reach main.

With the GCC versions you are using, not sure if the watchdog is disabled or not during initialisation of the .bss or .data sections, but see https://e2e.ti.com/support/development_tools/code_composer_studio/f/81/t/479645#pi316318=1 and https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/354527 for some ideas of how to check if the watchdog is disabled or not.

0 Jongsoo Jeong over 9 years ago in reply to Chester Gillon

Prodigy 100 points

With your help, I checked the watchdog problem, and I finally found official approach for 4.0.0.900 to fix it.

#include <msp430.h>
static void __attribute__((naked, section(".crt_0042"), used))
disable_watchdog (void)
{
    WDTCTL = WDTPW | WDTHOLD;
}

Inserting above code somewhere fixes the problem.

Thank you!

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Binary made by msp430-elf-g++ does not work when the BSS is too big.