If the watchdog is reconfigured from interrupt mode to reset mode while WDINT is still active low, then the
device will reset immediately. The WDINTS bit in the SCSR register can be read to determine the current
state of the WDINT signal before reconfiguring the watchdog to reset mode.
1.3.4.3 Watchdog Operation in Low-power Modes
In STANDBY mode, all of the clocks to the peripherals are turned off on the device. The only peripheral that
remains functional is the watchdog since the watchdog module runs off the oscillator clock (OSCCLK). The
WDINT signal is fed to the Low Power Modes (LPM) block so that it can be used to wake the device from
STANDBY low power mode (if enabled). See the Low Power Modes Block section of the device datasheet for
details.
In IDLE mode, the watchdog interrupt ( WDINT) signal can generate an interrupt to the CPU to take the CPU out
of IDLE mode. The watchdog is connected to the WAKEINT interrupt in the PIE.
Note
If the watchdog interrupt is used to wake-up from an IDLE or STANDBY low power mode condition,
then make sure that the WDINT signal goes back high again before attempting to go back into
the IDLE or STANDBY mode. The WDINT signal will be held low for 512 OSCCLK cycles when
the watchdog interrupt is generated. You can determine the current state of WDINT by reading the
watchdog interrupt status bit (WDINTS) bit in the SCSR register. WDINTS follows the state of WDINT
by two SYSCLKOUT cycles.
By using WDHALTI and INTOSC1HALTI bits, INTOSC1 and the watchdog module could be kept alive in HALT
mode. The device can then wake-up from HALT mode through the watchdog, but it is through the watchdog
reset, not the interrupt. When this happens, the RAM contents are not disturbed, but the peripherals will have to
be re-initialized.
1.3.4.4 Emulation Considerations
The watchdog module behaves as follows under various debug conditions:
CPU Suspended:
When the CPU is suspended, the watchdog clock (WDCLK) is suspended
Run-Free Mode:
When the CPU is placed in run-free mode, then the watchdog module resumes operation as normal.
Real-Time Single-Step Mode:
When the CPU is in real-time single-step mode, the watchdog clock (WDCLK) is suspended. The
watchdog remains suspended even within real-time interrupts.
Real-Time Run-Free Mode:
When the CPU is in real-time run-free mode, the watchdog operates as normal.
System Control and Interrupts
98
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Summary of Contents for TMS320 2806 Series
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