LP-MSP430FR2476: pointer troubles using FRAM for large code

Hi Florian,

Can you provide small code example showing this problem?

Sure, so here is a code fragment in which this occurs:

static int32_t mode_app_stop(struct v_mode *self)
{
    struct i2c_msg_t *i2c_msg;
    struct mode_app *app;

    app = member_of(self, struct mode_app, mode);
    i2c_msg = to_i2cmsg(app);

    i2c_msg->size = 0;
    .
    . // continues here but irrelevant
    .
}

and here is a screenshot from the debugger values after i2c_msg->size = 0. You can see nothing changes. A similar thing happens for memcpy operations on newly allocated pointers.

I can be sure, that it's not the code, since it's a third party driver code and I verified the behavior on another MCU with larger continuous RAM. On there the behavior is just as expected.

Edit:

To add here is an example for the memcpy issue:

memcpy(calib->data + calib->calib_len, i2c_msg->buf, len);

You can see after the command, the data in calib->data and i2c_msg->buf is still different. The only explanation I have for that would be the different memory locations, since this works on other platforms

Since the compiler is putting data into FRAM it is then vital that FRAM not be write protected. Or at least that section used for read/write data.

How do I make sure of this?

I guess it's related to this part of the linker file, but I don't think the symbol mentioned here is even defined, so the write protection shouldn't be active

#ifdef _FRWP_ENABLE
    __mpu_enable=1;
    start_protection_offset_address = (fram_rx_start - fram_rw_start) >> 10;
    program_fram_protection = 0x1;
    #ifdef _INFO_FRWP_ENABLE
        info_fram_protection = 0x1;
    #else
        info_fram_protection = 0x0;
    #endif
#endif

Florian Rohleder said:

I guess it's related to this part of the linker file, but I don't think the symbol mentioned here is even defined, so the write protection shouldn't be active

The _FRWP_ENABLE and _INFO_FRWP_ENABLE macros can be defined by CCS.

With CCS 11.1 created a new project for a MSP430FR2476 using the ti-cgt-msp430_21.6.0.LTS compiler. In the Project Properties under CCS General -> FRWP the "Enable FRAM Write Protection (FRWP)" and "Protect data FRAM memory (DFWP)" options were enabled:

And from the CCS Build console could see the _FRWP_ENABLE and _INFO_FRWP_ENABLE macros were being defined in the linker command line:

Invoking: MSP430 Linker
"/home/mr_halfword/ti/ccs1110/ccs/tools/compiler/ti-cgt-msp430_21.6.0.LTS/bin/cl430" -vmspx --use_hw_mpy=F5 --advice:power=all --advice:hw_config=all --define=__MSP430FR2476__ --define=_FRWP_ENABLE --define=_INFO_FRWP_ENABLE -g --printf_support=minimal --diag_warning=225 --diag_wrap=off --display_error_number --silicon_errata=CPU21 --silicon_errata=CPU22 --silicon_errata=CPU40 -z -m"MSP430FR2476_large_pointer.map" --heap_size=160 --stack_size=160 --cinit_hold_wdt=on -i"/home/mr_halfword/ti/ccs1110/ccs/ccs_base/msp430/include" -i"/home/mr_halfword/ti/ccs1110/ccs/ccs_base/msp430/lib/FR2xx" -i"/home/mr_halfword/ti/ccs1110/ccs/tools/compiler/ti-cgt-msp430_21.6.0.LTS/lib" -i"/home/mr_halfword/ti/ccs1110/ccs/tools/compiler/ti-cgt-msp430_21.6.0.LTS/include" --priority --reread_libs --define=_FRWP_ENABLE --define=_INFO_FRWP_ENABLE --diag_wrap=off --display_error_number --warn_sections --xml_link_info="MSP430FR2476_large_pointer_linkInfo.xml" --use_hw_mpy=F5 --rom_model -o "MSP430FR2476_large_pointer.out" "./main.obj" "../lnk_msp430fr2476.cmd"  -lfrwp_init.a -llibc.a 
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