LAUNCHXL-CC26X2R1: RAM is cleared after reset

Netanel Unger

Part Number: LAUNCHXL-CC26X2R1
Other Parts Discussed in Thread: CC2650

I have a code that runs on the CC2650, there is a __no_init (IAR) definition to a variable that needs to keep his value after reset happens and it's works grate.

But when the same code runs on CC26X2R1, the variable is getting the value 0 (has been written another value before the reset happen) after watchdog timer has reset the system.

Is there any known issue about it?

over 7 years ago

0 Severin Suveren over 7 years ago

TI__Mastermind 23730 points

Hi Netanel,

Can you provide a minimal code example that generates this error? Also, what IAR version are you using?

0 Netanel Unger over 7 years ago in reply to Severin Suveren

Expert 1190 points

Code is simple as you think:

1. init the WDT:

Watchdog_init();

Watchdog_Params wp;
Watchdog_Params_init(&wp);
wp.callbackFxn = (Watchdog_Callback)Hal_WDTCallback;
wp.debugStallMode = Watchdog_DEBUG_STALL_ON;
wp.resetMode = Watchdog_RESET_ON;

hWDT = Watchdog_open(0, &wp);

uint32_t tickValue;
tickValue = Watchdog_convertMsToTicks(hWDT, 3000);
Watchdog_setReload(hWDT, tickValue);

if (hWDT == NULL) {
while(1);
}

2. init variable:

__no_init UTCTime UTC_timeSeconds;

3. somewhere in the code (in our case it's a command received from UART to set the time)

UTC_timeSeconds = ....;

4. stuck the mcu with uart command,

while (1);

5. the mcu will reset after 3 seconds.

6. on init read UTC_timeSeconds and send it over uart, it's 0.

IAR ver 8.22.2

simplelink_cc26x2_sdk_1_60_00_43

0 Severin Suveren over 7 years ago in reply to Netanel Unger

TI__Mastermind 23730 points

Netanel,

The issue here is that tickValue is placed in RAM, and a Watchdog reset causes a HW reset of the entire RAM section, essentially clearing out the tickValue variable. __no_init does indicate to the C run-time to not initialize the tickCount variable at application startup, however, this does not guard the variable from being cleared by a RAM reset.

I'm wondering, is it non-volatile storage (NVS) you are looking after? Then there are a couple of options:
1. Using the NVS driver to either store the variable on the internal flash or on the external flash.
2. Storing the variable in AUX RAM. This might be problematic if you are planning to use the Sensor Controller.

0 Netanel Unger over 7 years ago in reply to Severin Suveren

Expert 1190 points

The value used for real time clock, and it being saved every 1 second. so to save power we prefers to save it in RAM.

how can i save the value in the AUX RAM ?

0 Severin Suveren over 7 years ago in reply to Netanel Unger

TI__Mastermind 23730 points

Please elaborate why you want to save the real time clock every second? I'm curious.

To store a value into AUX RAM, simply create a pointer to your desired location and dereference the pointer. E.g.

#include <ti/devices/DeviceFamily.h>
#include DeviceFamily_constructPath(inc/hw_memmap.h)

#define TICK_COUNT_OFFSET (0)
#define TICK_COUNT_ADDR   (AUX_RAM_BASE + TICK_COUNT_OFFSET)

// Should be volatile
volatile uint32_t * const pTickCount = (uint32_t*)TICK_COUNT_ADDR;

/* Writing variable */
*pTickCount = 42;
/* Reading variable */
uint32_t storedCount = *pTickCount;

0 Netanel Unger over 7 years ago in reply to Severin Suveren

Expert 1190 points

Hi,
It seems to work fine, very cool.
You are right, update the var every 1 second is too much, we will tell the client :)

0 Severin Suveren over 7 years ago in reply to Netanel Unger

TI__Mastermind 23730 points

I'm not sure I got what you meant at the end there. Setting an offset of 0 is fine. The only constraint is that variables stored in AUX_RAM doesn't overlap.

0 Netanel Unger over 7 years ago in reply to Severin Suveren

Expert 1190 points

you are right, my mistake.

Bluetooth®︎

Bluetooth forum

LAUNCHXL-CC26X2R1: RAM is cleared after reset