Writing uint64_t on a specific memory address.

RE: Writing uint64_t on a specific memory address.

Håkon Alseth — Mon, 14 Oct 2024 14:45:11 GMT

Hi,

Here's the partition manager documentation:

https://docs.nordicsemi.com/bundle/ncs-2.6.2/page/nrf/scripts/partition_manager/partition_manager.html#configuring_static_partitions

Kind regards,

Håkon

RE: Writing uint64_t on a specific memory address.

Epasta — Mon, 14 Oct 2024 14:37:07 GMT

Hello,

can you provide me a sample or documentation?
This is very unclear fo me.

thanks
best regards

RE: Writing uint64_t on a specific memory address.

Håkon Alseth — Mon, 14 Oct 2024 14:29:45 GMT

Hi,

You should use the original build folders build/partitions.yml as a static layout for future DFU images.

This means that you shall copy the original_project/build-folder/partitions.yml to my_updated_project/pm_static.yml to keep the original static partition layout.

Kind regards,

Håkon

RE: Writing uint64_t on a specific memory address.

Epasta — Mon, 14 Oct 2024 10:33:28 GMT

Hello,

it is difficult that can change but could be.

I did it with overlay file and it works perfectly how I would like.

Now I have enabled ota, but overlay file it does not work anymore.
Which is the correct file now to handle?

I read that i have to change pm_static.yml but i doesn't have this file in my project.
I tried to change partitions.yml but when I build it come back to default.

can you help me?

Thanks again for your time.

Best regards

RE: Writing uint64_t on a specific memory address.

Håkon Alseth — Mon, 30 Sep 2024 12:54:13 GMT

Hi,

It is unclear to me if this variable/number can change or not, based on your description.

If you cannot use UICR, then I would recommend the settings subsys, or set aside a specific page/section for your user-specified data at the end of flash.

Kind regards,

Håkon

RE: Writing uint64_t on a specific memory address.

Epasta — Mon, 30 Sep 2024 12:34:48 GMT

No, I do not need to be able to erase and re-write "my_id_number".
I just need to set it one time, keep it in a specific memory address and read it every time at power on.

It can happens that this number could be change in the future. UICR.OTP[] is not good for us.

Can you provide me a sample?

Thanks

RE: Writing uint64_t on a specific memory address.

Håkon Alseth — Mon, 30 Sep 2024 10:31:10 GMT

Hi,

Using a linker script to place a variable at a absolute address is possible, but you have to be aware that the linker does not handle fragmentation well. For example, if you place a var inside a region, such as "FLASH", the linker will not split up the region and handle any gaps in address space.

The recommendation if you need to both read and write to a region is to place the region at the end of your flash layout, and address it.

Do you need to be able to erase and re-write the "my_id_number"? If not, I would then recommend to look at the UICR.OTP[] area for storing a specific ID.

Kind regards,

Håkon

RE: Writing uint64_t on a specific memory address.

Epasta — Mon, 30 Sep 2024 10:10:25 GMT

Hello all,

i have edited main.c like follow:

void write_memory_id_number_(void){
    const struct device *flash_id;
    struct flash_area *fa;
    uint64_t my_id_number = 0x1500080507032592;
    uint64_t data_read;
    int rc;
    
    /*DON'T REMOVE THE COMMENTS HERE BELOW... IT WILL NOT WORK*/
    /*flash_id = device_get_binding("flash_id_number");
    if (!flash_id) {
        printk("Error\n");
        return;
    }*/

    rc = flash_area_open(FLASH_AREA_ID(flash_id_number), &fa);
    if (rc != 0) {
        printk("Error flash_id_number: %d\n", rc);
        return;
    }

    rc = flash_area_erase(fa, 0, fa->fa_size);
    if (rc != 0) {
        printk("Error flash_id_number: %d\n", rc);
        flash_area_close(fa);
        return;
    }

    rc = flash_area_write(fa, 0, &my_id_number, sizeof(my_id_number));
    if (rc != 0) {
        printk("Errore flash_id_number: %d\n", rc);
    } 

    rc = flash_area_read(fa, 0, &data_read, sizeof(data_read));
    if (rc != 0) {
        printk("Error: %d\n", rc);
    } else if (data_read == my_id_number) {
        printk("OK \n");
    } else {
        printk("Error:  0x%x no equals to 0x%x\n", data_read, my_id_number);
    }

    flash_area_close(fa);
}

edited .overlay file like follow:

    partitions {
        compatible = "fixed-partitions";
        #address-cells = < 0x1 >;
        #size-cells = < 0x1 >;
        boot_partition: partition@0 {
            label = "mcuboot";
            reg = < 0x0 0xc000 >;
        };
        slot0_partition: partition@c000 {
            label = "image-0";
            reg = < 0xc000 0x75000 >;
        };

        flash_id_number: partition@81000 {
            label = "flash_id_number";
            reg = < 0x81000 0x1000 >;
        };
        slot1_partition: partition@82000 {
            label = "image-1";
            reg = < 0x82000 0x76000 >;
        };
        storage_partition: partition@f8000 {
            label = "storage";
            reg = < 0xf8000 0x8000 >;
        };
    };

I can save data in flash file. But if i change memory address doesn't on hex file.
It is correct what i do?
Where I'm wrong?

RE: Writing uint64_t on a specific memory address.

Epasta — Mon, 30 Sep 2024 07:07:35 GMT

Hello,

I think I will use .overlay file, but, is there a guide that show how change the memory in .overlay file?
Do you have an example?

Best regards

RE: Writing uint64_t on a specific memory address.

Turbo J — Sat, 28 Sep 2024 08:36:50 GMT

Use either partiton manager or DTS (device tree overlay) if you don't use a bootloader. These allow modifications to code size and locations.

There is a config option that enables the linker to use the dts information for code size+location, but IIRC it only works when bootloader was not enabled.