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Tool/software: Code Composer Studio
I'm having trouble writing to a variable placed within a custom section of FRAM. I can read the value (0xFF) at each location, but cannot seem to update the value. It seems like there may be some sort of write protection happening that I am unaware of? I believe the MSP430FR2033 does not have an MPU, so I'm guessing that's not the problem.
In the simple test program below I can inspect the memory location of TestBuffer (located at 0xC400) and the values do not change. I can also see that read_test can read the initial value of TestBuffer[1] which is 0xFF, but the second read still returns 0xFF despite updating the value of TestBuffer[1] = 0x11.
I've also included the custom .cmd linker for reference. Any help would be appreciated.
main.c
#include <msp430.h>
#pragma DATA_SECTION(TestBuffer, ".log_buffer")
volatile unsigned char TestBuffer[10];
int main(void)
{
volatile unsigned char read_test = 0;
WDTCTL = WDTPW | WDTHOLD; // stop watchdog timer
read_test = TestBuffer[1];
TestBuffer[1] = 0x11;
read_test = TestBuffer[1];
TestBuffer[0] = 0x22;
return 0;
}lnk_msp430fr2033.cmd:
MEMORY
{
SFR : origin = 0x0000, length = 0x0010
PERIPHERALS_8BIT : origin = 0x0010, length = 0x00F0
PERIPHERALS_16BIT : origin = 0x0100, length = 0x0100
RAM : origin = 0x2000, length = 0x0800
INFOA : origin = 0x1800, length = 0x0200
LOG_BUFFER : origin = 0xC400, length = 0x0400
FRAM : origin = 0xC800, length = 0x3780
JTAGSIGNATURE : origin = 0xFF80, length = 0x0004, fill = 0xFFFF
BSLSIGNATURE : origin = 0xFF84, length = 0x0004, fill = 0xFFFF
INT00 : origin = 0xFF88, length = 0x0002
INT01 : origin = 0xFF8A, length = 0x0002
INT02 : origin = 0xFF8C, length = 0x0002
INT03 : origin = 0xFF8E, length = 0x0002
INT04 : origin = 0xFF90, length = 0x0002
INT05 : origin = 0xFF92, length = 0x0002
INT06 : origin = 0xFF94, length = 0x0002
INT07 : origin = 0xFF96, length = 0x0002
INT08 : origin = 0xFF98, length = 0x0002
INT09 : origin = 0xFF9A, length = 0x0002
INT10 : origin = 0xFF9C, length = 0x0002
INT11 : origin = 0xFF9E, length = 0x0002
INT12 : origin = 0xFFA0, length = 0x0002
INT13 : origin = 0xFFA2, length = 0x0002
INT14 : origin = 0xFFA4, length = 0x0002
INT15 : origin = 0xFFA6, length = 0x0002
INT16 : origin = 0xFFA8, length = 0x0002
INT17 : origin = 0xFFAA, length = 0x0002
INT18 : origin = 0xFFAC, length = 0x0002
INT19 : origin = 0xFFAE, length = 0x0002
INT20 : origin = 0xFFB0, length = 0x0002
INT21 : origin = 0xFFB2, length = 0x0002
INT22 : origin = 0xFFB4, length = 0x0002
INT23 : origin = 0xFFB6, length = 0x0002
INT24 : origin = 0xFFB8, length = 0x0002
INT25 : origin = 0xFFBA, length = 0x0002
INT26 : origin = 0xFFBC, length = 0x0002
INT27 : origin = 0xFFBE, length = 0x0002
INT28 : origin = 0xFFC0, length = 0x0002
INT29 : origin = 0xFFC2, length = 0x0002
INT30 : origin = 0xFFC4, length = 0x0002
INT31 : origin = 0xFFC6, length = 0x0002
INT32 : origin = 0xFFC8, length = 0x0002
INT33 : origin = 0xFFCA, length = 0x0002
INT34 : origin = 0xFFCC, length = 0x0002
INT35 : origin = 0xFFCE, length = 0x0002
INT36 : origin = 0xFFD0, length = 0x0002
INT37 : origin = 0xFFD2, length = 0x0002
INT38 : origin = 0xFFD4, length = 0x0002
INT39 : origin = 0xFFD6, length = 0x0002
INT40 : origin = 0xFFD8, length = 0x0002
INT41 : origin = 0xFFDA, length = 0x0002
INT42 : origin = 0xFFDC, length = 0x0002
INT43 : origin = 0xFFDE, length = 0x0002
INT44 : origin = 0xFFE0, length = 0x0002
INT45 : origin = 0xFFE2, length = 0x0002
INT46 : origin = 0xFFE4, length = 0x0002
INT47 : origin = 0xFFE6, length = 0x0002
INT48 : origin = 0xFFE8, length = 0x0002
INT49 : origin = 0xFFEA, length = 0x0002
INT50 : origin = 0xFFEC, length = 0x0002
INT51 : origin = 0xFFEE, length = 0x0002
INT52 : origin = 0xFFF0, length = 0x0002
INT53 : origin = 0xFFF2, length = 0x0002
INT54 : origin = 0xFFF4, length = 0x0002
INT55 : origin = 0xFFF6, length = 0x0002
INT56 : origin = 0xFFF8, length = 0x0002
INT57 : origin = 0xFFFA, length = 0x0002
INT58 : origin = 0xFFFC, length = 0x0002
RESET : origin = 0xFFFE, length = 0x0002
}
/****************************************************************************/
/* Specify the sections allocation into memory */
/****************************************************************************/
SECTIONS
{
GROUP(ALL_FRAM)
{
GROUP(READ_WRITE_MEMORY)
{
.TI.persistent : {} /* For #pragma persistent */
}
GROUP(READ_ONLY_MEMORY)
{
.cinit : {} /* Initialization tables */
.pinit : {} /* C++ constructor tables */
.binit : {} /* Boot-time Initialization tables */
.init_array : {} /* C++ constructor tables */
.mspabi.exidx : {} /* C++ constructor tables */
.mspabi.extab : {} /* C++ constructor tables */
.const : {} /* Constant data */
}
GROUP(EXECUTABLE_MEMORY)
{
.text : {} /* Code */
}
} > FRAM
#ifdef __TI_COMPILER_VERSION__
#if __TI_COMPILER_VERSION__ >= 15009000
#ifndef __LARGE_DATA_MODEL__
.TI.ramfunc : {} load=FRAM, run=RAM, table(BINIT)
#else
.TI.ramfunc : {} load=FRAM | FRAM2, run=RAM, table(BINIT)
#endif
#endif
#endif
.jtagsignature : {} > JTAGSIGNATURE /* JTAG Signature */
.bslsignature : {} > BSLSIGNATURE /* BSL Signature */
.bss : {} > RAM /* Global & static vars */
.data : {} > RAM /* Global & static vars */
.TI.noinit : {} > RAM /* For #pragma noinit */
.cio : {} > RAM /* C I/O buffer */
.sysmem : {} > RAM /* Dynamic memory allocation area */
.stack : {} > RAM (HIGH) /* Software system stack */
.infoA (NOLOAD) : {} > INFOA /* MSP430 INFO FRAM Memory segments */
.log_buffer : {} > LOG_BUFFER
/* MSP430 Interrupt vectors */
.int00 : {} > INT00
.int01 : {} > INT01
.int02 : {} > INT02
.int03 : {} > INT03
.int04 : {} > INT04
.int05 : {} > INT05
.int06 : {} > INT06
.int07 : {} > INT07
.int08 : {} > INT08
.int09 : {} > INT09
.int10 : {} > INT10
.int11 : {} > INT11
.int12 : {} > INT12
.int13 : {} > INT13
.int14 : {} > INT14
.int15 : {} > INT15
.int16 : {} > INT16
.int17 : {} > INT17
.int18 : {} > INT18
.int19 : {} > INT19
.int20 : {} > INT20
.int21 : {} > INT21
.int22 : {} > INT22
.int23 : {} > INT23
.int24 : {} > INT24
.int25 : {} > INT25
.int26 : {} > INT26
.int27 : {} > INT27
.int28 : {} > INT28
.int29 : {} > INT29
.int30 : {} > INT30
.int31 : {} > INT31
.int32 : {} > INT32
.int33 : {} > INT33
.int34 : {} > INT34
.int35 : {} > INT35
.int36 : {} > INT36
.int37 : {} > INT37
.int38 : {} > INT38
.int39 : {} > INT39
.int40 : {} > INT40
.int41 : {} > INT41
.int42 : {} > INT42
.int43 : {} > INT43
.int44 : {} > INT44
.int45 : {} > INT45
PORT2 : { * ( .int46 ) } > INT46 type = VECT_INIT
PORT1 : { * ( .int47 ) } > INT47 type = VECT_INIT
ADC : { * ( .int48 ) } > INT48 type = VECT_INIT
USCI_B0 : { * ( .int49 ) } > INT49 type = VECT_INIT
USCI_A0 : { * ( .int50 ) } > INT50 type = VECT_INIT
WDT : { * ( .int51 ) } > INT51 type = VECT_INIT
RTC : { * ( .int52 ) } > INT52 type = VECT_INIT
TIMER1_A1 : { * ( .int53 ) } > INT53 type = VECT_INIT
TIMER1_A0 : { * ( .int54 ) } > INT54 type = VECT_INIT
TIMER0_A1 : { * ( .int55 ) } > INT55 type = VECT_INIT
TIMER0_A0 : { * ( .int56 ) } > INT56 type = VECT_INIT
UNMI : { * ( .int57 ) } > INT57 type = VECT_INIT
SYSNMI : { * ( .int58 ) } > INT58 type = VECT_INIT
.reset : {} > RESET /* MSP430 Reset vector */
}
/****************************************************************************/
/* Include peripherals memory map */
/****************************************************************************/
-l msp430fr2033.cmd
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