How to Perform Segment Erase using MSP430 USB Firmware Upgrade Example v1.3.0

Hi,

The tool you mentioned has the ability to perform segment erase.

If the password supplied in password.Text field at Firmware.resx file matches corresponding value of your old firmware, only segments necessary for flashing new firmware will be erased.

If the password does not match, bulk erase is performed (all flash memory segments are erased) even though your new firmware has only 1 segment in size.

The password as you are probably aware uses as its value 16 words in MSP430 vectors area.

You'll need to re-compile the MSP430 USB Firmware Upgrade Example v1.3.0 code with the new password. 

BTW, there is newer version of the tool available, 1.3.1, at TI website, which fixes several bugs.

Hi Deep,

1. The snapshot you've provided does not have any clues of where the password is. Normally it starts at address FFE0 and occupies 32 bytes up to address FFFF. Do you have at your firmware .txt file some labels with addresses (like @ffca, for example) ? You'll need somehow locate area FFE0...FFFF in your .txt file

2. Because of password is located at the flash area where the interrupt vectors are located, every time you change your firmware there is a chance that this area gets changed as well. So the password as well, and you'll have to keep track of the password changes, otherwise while upgrading the firmware if you enter the password which is not valid any more bulk erase occurs wiping out all of your flash including the segments that you may use as a parameters storage and want to be preserved...

The document you mentioned (slaa452b)  means that fixed address values are assigned to 16 vectors located in FFE0...FFFF area, and this addresses point to entries in a jump table. This table has 16 entries, each entry has a jump instruction to corresponding ISR. This table is located at fixed location in memory, so when you change your ISRs, the table entries are changed, but not the table location, so the FFE0...FFFF area is not changed and password stays fixed.

There is a simpler way: specify 'location' pragmas for your ISRs, which places ISRs at fixed addresses in memory. But what if in new revision of your firmware your ISR(s) change in size? You'll have to change 'fixed' addresses breaking password consistency again...

The issue with BSL password is so annoying, that for the projects which must have an option to preserve specified flash segments no matter what (they can contain factory calibration data, for example; lost of this data means sending product back to the factory for re-calibration) the custom BSL creation can be considered. The custom BSL can either disable password completely, or move it to the area when it can not clash with IRQ vectors.

Hi Deep,

For IAR toolchain address of the program entry point is usually fixed to the value of 0x8000, which is usually start of the flash for many MSP430 devices. Though it is not necessary, it could be any other address within first 64KB of flash area convenient for your application.

For CCS in order to do that, you'll need to edit your linker script .cmd  file, for example, like this:

/****************************************************************************/

/* SPECIFY THE SECTIONS ALLOCATION INTO MEMORY                              */

/****************************************************************************/

SECTIONS

{

    .bss        : {} > RAM                /* GLOBAL & STATIC VARS              */

    .data       : {} > RAM                /* GLOBAL & STATIC VARS              */

    .sysmem     : {} > RAM                /* DYNAMIC MEMORY ALLOCATION AREA    */

    .stack      : {} > RAM (HIGH)         /* SOFTWARE SYSTEM STACK             */

    .text:_isr:_c_int00_noexit : {} > 0x8000 /* Entry point abs. address */

    .text       : {}>> FLASH | FLASH2     /* CODE                              */

    .text:_isr  : {} > FLASH              /* ISR CODE SPACE                    */

. . .

Best regards,

Serge