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Green rectangular circuit board with 40-pin header and battery holder

WaveShare

WaveShare RTC WatchDog HAT for Raspberry Pi and Jetson Nano computer accessory

SKU CH-0K28-AG9VQ

Adds a DS3231SN real-time clock and a MAX705 watchdog with auto-reset to Raspberry Pi or Jetson Nano via the 40-pin GPIO header

  • CPU TypeOther
  • Hardware watchdog auto-resets frozen boards via MAX705 circuit
  • Precise timekeeping maintained by DS3231SN RTC with battery backup
  • Fits Raspberry Pi series and Jetson Nano through 40-pin GPIO header
  • Selectable reset pin lets you tailor watchdog behaviour
  • Visual warning indicator shows watchdog output status instantly

Compatible Boards

The WaveShare RTC WatchDog HAT fits the standard Raspberry Pi 40PIN GPIO header and works with Raspberry Pi series boards as well as the Jetson Nano. It adds a hardware watchdog and a real-time clock to those platforms in a single add-on board.

Practical Limits

The watchdog relies on the MAX705 monitoring circuit with an auto reset function, so recovery is handled by that specific chip rather than by software alone. Timekeeping depends on the DS3231SN high precision RTC chip and requires a backup battery to maintain the clock when main power is removed.

Installation Notes

The HAT mounts directly onto the 40-pin header without extra cabling, but the reset pin selection jumper must be set correctly for the watchdog to trigger a reset. A missing or poorly seated backup battery is the most common reason the RTC loses time after a power cycle.

Highlights

  • Hardware watchdog auto-resets frozen boards via MAX705 circuit
  • Precise timekeeping maintained by DS3231SN RTC with battery backup
  • Fits Raspberry Pi series and Jetson Nano through 40-pin GPIO header
  • Selectable reset pin lets you tailor watchdog behaviour
  • Visual warning indicator shows watchdog output status instantly

Specifications

CPU TypeOther

Questions about this item

Which Raspberry Pi or Jetson boards will this HAT fit?

The board uses a standard Raspberry Pi 40PIN GPIO header, so it mounts on any Raspberry Pi model with that header and on a Jetson Nano.

What does the MAX705 monitoring circuit actually do for my system?

The MAX705 watches the supply voltage and asserts a hardware reset if power drops below its threshold, then releases the reset automatically when power recovers.

How does the DS3231SN RTC connect and what limits its accuracy?

The DS3231SN talks over the I2C bus on the GPIO header; its integrated temperature-compensated oscillator keeps time within a few seconds per month while the backup battery maintains the clock when main power is off.

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