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cc2538: lpm: Give access to the SRAM non-retention area for PM2 

If PM2 is enabled with LPM_CONF_MAX_PM, but not active, the non-retention area
of the SRAM can be useful to place temporary data that does not fit in the
low-leakage SRAM, typically after having called lpm_set_max_pm(LPM_PM1). Hence,
give access to this non-retention area thanks to .nrdata* sections.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
This commit is contained in:
Benoît Thébaudeau 2013-11-25 15:43:37 +01:00
parent acee82abbb
commit 621f4f7339
2 changed files with 24 additions and 4 deletions
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22
cpu/cc2538/cc2538.lds
View File

@ -34,17 +34,22 @@
* ld script, which is called cc2538.ld and will be in the project directory
*/
#if (LPM_CONF_MAX_PM==2) && (LPM_CONF_ENABLE != 0)
#define SRAM_START 0x20004000
#define SRAM_LEN 0x00004000
#define NRSRAM_START 0x20000000
#define NRSRAM_LEN 0x00004000
#define SRAM_START 0x20004000
#define SRAM_LEN 0x00004000
#else
#define SRAM_START 0x20000000
#define SRAM_LEN 0x00008000
#define SRAM_START 0x20000000
#define SRAM_LEN 0x00008000
#endif
MEMORY
{
FLASH (rx) : ORIGIN = 0x200000, LENGTH = 0x0007FFD4
FLASH_CCA (RX) : ORIGIN = 0x0027FFD4, LENGTH = 12
#if (LPM_CONF_MAX_PM==2) && (LPM_CONF_ENABLE != 0)
NRSRAM (RWX) : ORIGIN = NRSRAM_START, LENGTH = NRSRAM_LEN
#endif
SRAM (RWX) : ORIGIN = SRAM_START, LENGTH = SRAM_LEN
}
@ -80,6 +85,15 @@ SECTIONS
_ebss = .;
} > SRAM
#if (LPM_CONF_MAX_PM==2) && (LPM_CONF_ENABLE != 0)
.nrdata :
{
_nrdata = .;
*(.nrdata*)
_enrdata = .;
} > NRSRAM
#endif
.flashcca :
{
KEEP(*(.flashcca))

6
cpu/cc2538/lpm.h
View File

@ -126,6 +126,12 @@ void lpm_init(void);
* lpm_exit(), which will always be called from within the Sleep Timer ISR
* context.
*
* \note Dropping to PM2 means that data in the SRAM non-retention area will
* be lost. It is recommended to disable PM2 if the total RAM footprint is
* larger than what will fit in the retention area.
* .nrdata* sections can be used to place uninitialized data in the SRAM
* non-retention area.
*
* \sa main(), rtimer_arch_next_trigger(), lpm_exit(), lpm_set_max_pm()
*/
void lpm_enter(void);