can we run soft device from RAM instead of flash?

RE: can we run soft device from RAM instead of flash?

ys parmar — Mon, 14 Sep 2020 11:17:48 GMT

as per your suggestion i am using like this in bilnky example

#pragma long_calls

__attribute__((used, long_calls, section(".data"))) int main(void)
{
/* Configure board. */
bsp_board_init(BSP_INIT_LEDS);

/* Toggle LEDs. */
while (true)
{
for (int i = 0; i < LEDS_NUMBER; i++)
{
bsp_board_led_invert(i);
nrf_delay_ms(500);
}
}
}

but we get same error

bilnkyoutsdh/Applications/main.c:66:(.data+0x6): relocation truncated to fit: R_ARM_THM_CALL against symbol `bsp_board_init' defined in .text.bsp_board_init section in _build/nrf52840_xxaa_boards.c.o
bilnkyoutsdh/Applications/main.c:73:(.data+0x12): relocation truncated to fit: R_ARM_THM_CALL against symbol `bsp_board_led_invert' defined in .text.bsp_board_led_invert section in _build/nrf52840_xxaa_boards.c.o
collect2.exe: error: ld returned 1 exit status

RE: can we run soft device from RAM instead of flash?

Turbo J — Sat, 12 Sep 2020 08:43:27 GMT

The gcc ARM documentaion suggests using

#pragma long_calls

as workaround.

ARM Cortex-M cannot use a single instruction to call functions outside a ±16MB range, and thus won't be able to call flash from RAM. Workaround is to put the address into a register and use this for the call (BLX).

RE: can we run soft device from RAM instead of flash?

ys parmar — Sat, 12 Sep 2020 08:29:49 GMT

and i am also using data section but its give error

s/main.c:38:(.data+0x2): relocation truncated to fit: R_ARM_THM_CALL against symbol `ble_init' defined in .text.ble_init section in _build/nrf52840_xxaa_Ble_Interface.c.o

RE: can we run soft device from RAM instead of flash?

ys parmar — Sat, 12 Sep 2020 08:27:27 GMT

and can the application run from ram and linked with soft device ? because soft device run from flash so i am confused. can those be linked

RE: can we run soft device from RAM instead of flash?

Turbo J — Sat, 12 Sep 2020 08:19:41 GMT

The .noinit section won't be populated with code - no initialization means random data (empty on POR).

Try just using ".data" section. The startup code must copy your function from flash to RAM, this is always done for the data section.

Note: Your NO_INIT section seems to be waaaaay bigger than available RAM, and it overlaps the actual RAM section. Both are not a good idea.

RE: can we run soft device from RAM instead of flash?

ys parmar — Fri, 11 Sep 2020 11:29:20 GMT

ok thanks let see. and i have one issue .

i am trying to run our code from ram instead of flash in nrf52840. in linker file we create one section like this

MEMORY
{
FLASH (rx) : ORIGIN = 0x26000, LENGTH = 0xda000
RAM (rwx) : ORIGIN = 0x20003bb8, LENGTH = 0x9000
NO_INIT (rwx) : ORIGIN = 0x20009000, LENGTH = 0x2400000
}

SECTIONS
{
}

SECTIONS
{
.no_init (NOLOAD):
{
PROVIDE(__start_no_init_data = .);
KEEP(*(SORT(.no_init*)))
PROVIDE(__stop_no_init_data = .);
} > NO_INIT
}

and use txn fxn

__attribute__((used, long_call, section(".no_init"))) void main(void)

{
ble_init();

}

code is succesfully build but in jlink we dont see any print msg and nrf connect dont see my device name . can u suggest me how can i run our main fxn in ram instead of flash

RE: can we run soft device from RAM instead of flash?

Turbo J — Fri, 11 Sep 2020 11:25:35 GMT

Nope. SD must run from flash. Google: Static linking in C language.

Note that there is next to nothing to save in current consumtion - SD runs often, but not for a long time.