CC1310: Flash sector write/erase protection disable.

Hi,

the last bytes in the last flash page are reserved for the Customer Configuration (CCFG). This area contains also flash protection configuration. You must ensure that the CCFG area is not overwritten by your application. Otherwise you may lock yourself out of the chip by disabling JTAG and enabling erase and write protect on all pages.

In order to control flash write protection, you may set SET_CCFG_CCFG_PROT_XXX to 0:

/*
 *  ======== ccfg.c ========
 *  Customer Configuration for CC26xx and CC13xx devices.  This file is used to
 *  configure Boot ROM, start-up code, and SW radio behaviour.
 *
 *  By default, driverlib startup_files/ccfg.c settings are used.  However, if
 *  changes are required there are two means to do so:
 *
 *    1.  Remove this file and copy driverlib's startup_files/ccfg.c file in
 *        its place.  Make all changes to the file.  Changes made are local to
 *        the project and will not affect other projects.
 *
 *    2.  Perform changes to driverlib startup_files/ccfg.c file.  Changes
 *        made to this file will be applied to all projects.  This file must
 *        remain unmodified.
 */

// Set one of the bits to low to enable write protection on these flash pages.
#define SET_CCFG_CCFG_PROT_127_96                       0xFFFFFFFF

#include <ti/devices/DeviceFamily.h>
#include DeviceFamily_constructPath(startup_files/ccfg.c)

In the IAR linker script file, the ccfg section is linked to the end of flash:

/* Place the CCA area at the end of flash */
place at end of FLASH_region { readonly section .ccfg };
keep { section .ccfg };

Flash_region is defined as follows:

/* Define a region for the on-chip flash */
define region FLASH_region   = mem:[from ROM_start__ to ROM_end__];

Changing ROM_end__ will also cause the ccfg section being linked to a wrong address. Therefore, you cannot just change ROM_end__, but you have to introduce a new section for ccfg. For instance:

define symbol CCFG_start__ = 0x0001FFA8;
define symbol CCFG_end__   = 0x0001FFFF;

/* Define a region for the ccfg */
define region CCFG_region   = mem:[from CCFG_start__ to CCFG_end__];

/* Place the CCA area at the end of flash */
place at end of CCFG_region { readonly section .ccfg };
keep { section .ccfg };

I hope this makes things clear.

Hi,

wording:

• A page is 4 KiB large. This is the minimum erasable unit
• A sector is a small part of a page. Each sector can be erase and write protected

I do not recommend to use the last 4 KiB page as a non-volatile data storage, but a page before. Although only few bytes are occupied by the CCFG, you cannot erase the whole page without losing CCFG information. Therefore, 

• use the last 4 KiB page for the application or a bootloader or other data that does never change
• use the 2 pages before that for you data
• Create a separate memory segment for the CCFG section as I have described in my previous post. You need to do this, otherwise, your CCFG data is linked to the wrong address.