Kinetis Microcontrollers中的主题 Re: Link global struct variable into FlexRAM memory

Link global struct variable into FlexRAM memory

benjamin_doerne — Thu, 13 Feb 2020 13:23:21 GMT

Hi everyone,

In order to have a more human readable and also address care-free way to deal with the EEEPROM, my idea was as follows:

link a global struct variable into the FlexRAM memory area (starts at 0x14000000)
```
__DATA(FLEX_RAM) MyStruct myStructVariable;‍
```
Note: this is done above the main() function

read and write via the SDK function

writeToFlexRam((uint32_t)&myStructVariable.value1, (uint8_t*)&someValue, sizeof(someValue));‍

Unfortunately this leads to a hard fault. Whenever I link the variable to another RAM, let's say RAM2, no hard fault occurs.

What's wrong with my approach? Any ideas?

Thanks in advance

Benjo

Re: Link global struct variable into FlexRAM memory

kerryzhou — Fri, 14 Feb 2020 03:58:26 GMT

Hi benjamin.doerner@tecan.com ,

Please tell me your kineti chip partnumber, please make sure your chip contains the FLEXNVM or not?

If it contains the FlexNVM, whether you already use your FlexRAM as the EEPROM.

If your chip don't contains the FlexNVM, you can use your FlexRAM(make sure your chip has it).

I think you also can define your structure code in the normal RAM address, whether it works or not, just make sure it is not the code problem.

Wish it helps you!

If you still have questions about it, please kindly let me know.

Have a great day,
Kerry

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Re: Link global struct variable into FlexRAM memory

benjamin_doerne — Fri, 14 Feb 2020 07:57:41 GMT

Hi Kerry,

The chip I'm using is the MKE18F512VLL16 supporting both, the FlexNVM and FlexRAM.
To link the struct variable into a RAM other than RAM3 (aka FLEX_RAM) makes no sense because I want to use the variable instead of hard coded FlexRAM addresses (which is prone to errors, such as typos, miscalculations, etc.).

The section where I'd like to have the struct variable is

/* DATA section for FLEX_RAM */
.data_RAM3 : ALIGN(8)
 {
 FILL(0xff)
 PROVIDE(__start_data_RAM3 = .) ;
 *(.ramfunc.$RAM3)
 *(.ramfunc.$FLEX_RAM)
 *(.data.$RAM3)
 *(.data.$FLEX_RAM)
 *(.data.$RAM3.*)
 *(.data.$FLEX_RAM.*)
 . = ALIGN(8) ;
 PROVIDE(__end_data_RAM3 = .) ;
 } > FLEX_RAM AT>PROGRAM_FLASH‍‍‍‍‍‍‍‍‍‍‍‍‍‍

How I'd like to write to the EEEPROM:

writeToFlexRam((uint32_t)&myStructVariable.value1, (uint8_t*)&someValue, sizeof(someValue));‍

What I'd like to avoid:

writeToFlexRam((0x14000000, (uint8_t*)&someValue, sizeof(someValue));
writeToFlexRam((0x14000004, (uint8_t*)&someValue2, sizeof(someValue2));‍‍

Cheers,

Benjo

Re: Link global struct variable into FlexRAM memory

benjamin_doerne — Fri, 14 Feb 2020 13:01:25 GMT

Hi all,

found the solution myself. Instead of

__DATA(FLEX_RAM) MyStruct myStructVariable;‍

I used

__NOINIT(FLEX_RAM) MyStruct myStructVariable;‍

Now it works as expected.

Re: Link global struct variable into FlexRAM memory

kerryzhou — Sun, 16 Feb 2020 09:07:09 GMT

Hi benjamin.doerner@tecan.com ,

Thanks for sharing the solutions.

If you have the new question in the future, welcome to create the new case.

Have a great day,
Kerry

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