| Apollo Register Documentation v2.2.0

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WDT - Watchdog Timer

### WDT Register Index

0x00000000: | CFG - Configuration Register
0x00000004: | RSTRT - Restart the watchdog timer.
0x00000008: | LOCK - Locks the WDT
0x0000000C: | COUNT - Current Counter Value for WDT
0x00000200: | INTEN - WDT Interrupt register: Enable
0x00000204: | INTSTAT - WDT Interrupt register: Status
0x00000208: | INTCLR - WDT Interrupt register: Clear
0x0000020C: | INTSET - WDT Interrupt register: Set

### CFG - Configuration Register

### Address:

Instance 0 Address: | 0x40024000

### Description:

This is the configuration register for the watch dog timer. It controls the enable, interrupt set, clocks for the timer, the compare values for the counters to trigger a reset or interrupt. This register can only be written to if the watch dog timer is unlocked (WDTLOCK is not set).

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | CLKSEL 0x0 | INTVAL 0xff | RESVAL 0xff | RSVD 0x0 | RESEN 0x0 | INTEN 0x0 | WDTEN 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:27 | RSVD | RO | This bitfield is reserved for future use.
26:24 | CLKSEL | RW | Select the frequency for the WDT. All values not enumerated below are undefined. OFF = 0x0 - Low Power Mode. This setting disables the watch dog timer. 128HZ = 0x1 - 128 Hz LFRC clock. 16HZ = 0x2 - 16 Hz LFRC clock. 1HZ = 0x3 - 1 Hz LFRC clock. 1_16HZ = 0x4 - 1/16th Hz LFRC clock.
23:16 | INTVAL | RW | This bitfield is the compare value for counter bits 7:0 to generate a watchdog interrupt.
15:8 | RESVAL | RW | This bitfield is the compare value for counter bits 7:0 to generate a watchdog reset. This will cause a software reset.
7:3 | RSVD | RO | This bitfield is reserved for future use.
2 | RESEN | RW | This bitfield enables the WDT reset. This needs to be set together with the WDREN bit in REG_RSTGEN_CFG register (in reset gen) to trigger the reset.
1 | INTEN | RW | This bitfield enables the WDT interrupt. Note : This bit must be set before the interrupt status bit will reflect a watchdog timer expiration. The IER interrupt register must also be enabled for a WDT interrupt to be sent to the NVIC.
0 | WDTEN | RW | This bitfield enables the WDT.

### RSTRT - Restart the watchdog timer.

### Address:

Instance 0 Address: | 0x40024004

### Description:

This register will Restart the watchdog timer. Writing a special key value into this register will result in the watch dog timer being reset, so that the count will start again. It is expected that the software will periodically write to this register to indicate that the system is functional. The watch dog timer can continue running when the system is in deep sleep, and the interrupt will trigger the wake. After the wake, the core can reset the watch dog timer.

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | RSTRT 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:8 | RSVD | RO | This bitfield is reserved for future use.
7:0 | RSTRT | WO | Writing 0xB2 to WDTRSTRT restarts the watchdog timer. This is a write only register. Reading this register will only provide all 0. KEYVALUE = 0xB2 - This is the key value to write to WDTRSTRT to restart the WDT. This is a write only register.

### LOCK - Locks the WDT

### Address:

Instance 0 Address: | 0x40024008

### Description:

This register locks the watch dog timer. Once it is locked, the configuration register (WDTCFG) for watch dog timer cannot be written to.

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | LOCK 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:8 | RSVD | RO | This bitfield is reserved for future use.
7:0 | LOCK | WO | Writing 0x3A locks the watchdog timer. Once locked, the WDTCFG reg cannot be written and WDTEN is set. KEYVALUE = 0x3A - This is the key value to write to WDTLOCK to lock the WDT.

### COUNT - Current Counter Value for WDT

### Address:

Instance 0 Address: | 0x4002400C

### Description:

This register holds the current count for the watch dog timer. This is a read only register. SW cannot set the value in the counter, but can reset it.

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | COUNT 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:8 | RSVD | RO | This bitfield is reserved for future use.
7:0 | COUNT | RO | Read-Only current value of the WDT counter

### INTEN - WDT Interrupt register: Enable

### Address:

Instance 0 Address: | 0x40024200

### Description:

Set bits in this register to allow this module to generate the corresponding interrupt.

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | WDTINT 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:1 | RSVD | RO | This bitfield is reserved for future use.
0 | WDTINT | RW | Watchdog Timer Interrupt.

### INTSTAT - WDT Interrupt register: Status

### Address:

Instance 0 Address: | 0x40024204

### Description:

Read bits from this register to discover the cause of a recent interrupt.

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | WDTINT 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:1 | RSVD | RO | This bitfield is reserved for future use.
0 | WDTINT | RW | Watchdog Timer Interrupt.

### INTCLR - WDT Interrupt register: Clear

### Address:

Instance 0 Address: | 0x40024208

### Description:

Write a 1 to a bit in this register to clear the interrupt status associated with that bit.

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | WDTINT 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:1 | RSVD | RO | This bitfield is reserved for future use.
0 | WDTINT | RW | Watchdog Timer Interrupt.

### INTSET - WDT Interrupt register: Set

### Address:

Instance 0 Address: | 0x4002420C

### Description:

Write a 1 to a bit in this register to instantly generate an interrupt from this module. (Generally used for testing purposes).

### Example Macro Usage:

    //
    // Register access is all performed through the standard CMSIS structure-based
    // interface. This includes module-level structure definitions with members and
    // bitfields corresponding to the physical registers and bitfields within each
    // module. In addition, Ambiq has provided instance-level macros for modules
    // that have more than one physical instance and a generic AM_REGVAL() macro
    // for directly accessing memory by address.
    //
    // The following examples show how to use these structures and macros:

    // Setting the ADC configuration register...
    AM_REGVAL(0x50010000) = 0x1234;              // by address.
    ADC->CFG = 0x1234;                           // by structure pointer.
    ADCn(0)->CFG = 0x1234;                       // by structure pointer (with instance number).

    // Changing the ADC clock...
    ADCn(0)->CFG_b.CLKSEL = 0x2;                 // by raw value.
    ADCn(0)->CFG_b.CLKSEL = ADC_CFG_CLKSEL_HFRC; // using an enumerated value.

### Register Fields:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
RSVD 0x0 | WDTINT 0x0

Bits | Name | RW | Description
--- | --- | --- | ---
31:1 | RSVD | RO | This bitfield is reserved for future use.
0 | WDTINT | RW | Watchdog Timer Interrupt.