S32K144 Reconfigure disabled Watchdog

DynamicsNoDriver — Thu, 14 Mar 2024 01:06:57 GMT

I want to reconfigure the watchdog of the S32K144 after it has been disabled in the startup script. In the startup script there is following section that disables the watchdog:

/**************************************************************************/ /* WDOG DISABLE*/ /**************************************************************************/ #if (DISABLE_WDOG) /* Write of the WDOG unlock key to CNT register, must be done in order to allow any modifications*/ WDOG->CNT = (uint32_t ) FEATURE_WDOG_UNLOCK_VALUE; /* The dummy read is used in order to make sure that the WDOG registers will be configured only * after the write of the unlock value was completed. */ (void)WDOG->CNT; /* Initial write of WDOG configuration register: * enables support for 32-bit refresh/unlock command write words, * clock select from LPO, update enable, watchdog disabled */ WDOG->CS = (uint32_t ) ( (1UL << WDOG_CS_CMD32EN_SHIFT) | (FEATURE_WDOG_CLK_FROM_LPO << WDOG_CS_CLK_SHIFT) | (0U << WDOG_CS_EN_SHIFT) | (1U << WDOG_CS_UPDATE_SHIFT) ); /* Configure timeout */ WDOG->TOVAL = (uint32_t )0xFFFF; #endif /* (DISABLE_WDOG) */

If later on i try to reconfigure the watchdog which should be possible because the Allow Updates field of the Watchdog Control and Status Register is set, the watchdog configuration does not change. I use the following code:

DISABLE_INTERRUPTS() WDOG->CNT = 0xD928C520U; // Unlock watchdog while (!(WDOG->CS & WDOG_CS_ULK_MASK) != 0u) ; // Wait for wdog to be unlocked WDOG->WIN = 0x0000; WDOG->TOVAL = 50; WDOG->CS |= (WDOG_CS_CLK_MASK & (1 << WDOG_CS_CLK_SHIFT)); WDOG->CS |= WDOG_CS_INT_MASK; WDOG->CS |= WDOG_CS_EN_MASK; while (!((WDOG->CS & WDOG_CS_RCS_MASK) != 0u)) ; // Wait for config to be changed ENABLE_INTERRUPTS()

If I enable the watchdog on startup with this code:

/* Write of the WDOG unlock key to CNT register, must be done in order to allow any modifications*/ WDOG->CNT = (uint32_t ) FEATURE_WDOG_UNLOCK_VALUE; /* The dummy read is used in order to make sure that the WDOG registers will be configured only * after the write of the unlock value was completed. */ (void)WDOG->CNT; /* Initial write of WDOG configuration register: * enables support for 32-bit refresh/unlock command write words, * clock select from LPO, update enable, watchdog disabled */ WDOG->CS = (uint32_t ) ( (1UL << WDOG_CS_CMD32EN_SHIFT) | (FEATURE_WDOG_CLK_FROM_LPO << WDOG_CS_CLK_SHIFT) | (1U << WDOG_CS_EN_SHIFT) | (1U << WDOG_CS_UPDATE_SHIFT) ); /* Configure timeout */ WDOG->TOVAL = (uint32_t )0xFFFF;

I can reconfigure it later with the same reconfiguration code above. Is reconfiguration only possible when the watchdog is enabled?

Re: S32K144 Reconfigure disabled Watchdog

danielmartynek — Thu, 14 Mar 2024 13:03:02 GMT

Hi @DynamicsNoDriver,

Can you write WDOG->CS in just one write?

BR, Daniel

Re: S32K144 Reconfigure disabled Watchdog

DynamicsNoDriver — Thu, 14 Mar 2024 23:53:57 GMT

Hello @danielmartynek,
this works for me. Can you please explain why I need to write WDOG->CS in one write when the watchdog was disabled previously but it's possible to write to WDOG->CS multiple times when the watchdog was enabled before?

Re: S32K144 Reconfigure disabled Watchdog

danielmartynek — Fri, 15 Mar 2024 13:23:46 GMT

The WDOG stays unlock for just 128 BUS_CLK cycles.

You need to make sure the CS register gets written within the window.

Regards,

Daniel

topic S32K144 Reconfigure disabled Watchdog in S32K

S32K144 Reconfigure disabled Watchdog

Re: S32K144 Reconfigure disabled Watchdog

Re: S32K144 Reconfigure disabled Watchdog

Re: S32K144 Reconfigure disabled Watchdog