How to Use Adafruit TPL5111 Reset Enable Timer: Examples, Pinouts, and Specs

The Adafruit TPL5111 Reset Enable Timer is a breakout board designed to facilitate timed power cycling or enable/disable operations for electronic projects. This component is particularly useful for battery-powered applications where power conservation is crucial. By allowing scheduled wake-ups or resets, the TPL5111 helps in extending battery life and reducing power consumption.

• Power cycling microcontrollers or other electronics at set intervals
• Enabling or disabling peripherals to conserve power
• Scheduled wake-ups for data logging or sensor reading tasks
• IoT devices requiring periodic operation

• Supply Voltage (VDD): 1.8V to 5.5V
• Maximum Time Delay: 2 hours
• Minimum Time Delay: 100 ms
• Operating Current (VDD = 3.3V): 20 nA (typical)
• Maximum Allowable Current on DRV Pin: 20 mA

1. Connect Power: Attach VDD to your power supply (1.8V to 5.5V) and GND to the ground.
2. Set Delay: Connect a resistor between the DELAY pin and ground to set the desired delay interval.
3. Connect Drive Output: Attach the DRV pin to the reset or enable pin of the device you wish to control.
4. Signal Completion: Connect the DONE pin to a GPIO pin on your microcontroller to signal task completion.

• Ensure that the supply voltage does not exceed 5.5V to prevent damage to the TPL5111.
• Select a resistor for the DELAY pin based on the desired time interval using the formula provided in the TPL5111 datasheet.
• Avoid drawing more than 20 mA from the DRV pin.
• Use a pull-up resistor on the DONE pin if your microcontroller does not have an internal pull-up.

// Example code to use Adafruit TPL5111 with Arduino UNO

const int donePin = 2; // Connect this to the DONE pin on the TPL5111

void setup() {
  pinMode(donePin, OUTPUT);
  digitalWrite(donePin, LOW);
}

void loop() {
  // Perform your task here
  
  // Signal the TPL5111 that the task is done
  digitalWrite(donePin, HIGH);
  delay(100); // Wait for 100ms to ensure the signal is registered
  digitalWrite(donePin, LOW);
  
  // Enter sleep mode or perform low-power operations until the TPL5111 resets the system
}

• TPL5111 not resetting the device: Ensure that the DELAY pin is correctly configured with the appropriate resistor value.
• Device resets too quickly or too slowly: Double-check the resistor value connected to the DELAY pin and adjust it according to the datasheet formula.
• DRV pin not providing enough current: Verify that the current requirement of the target device's reset or enable pin does not exceed 20 mA.

• If the timer is not operating as expected, recheck all connections, especially the DELAY resistor and the DONE pin wiring.
• Use a multimeter to measure the voltage at the VDD pin to ensure that the TPL5111 is powered correctly.
• For issues related to timing accuracy, consider environmental factors such as temperature that might affect the resistor value.

Q: Can I use the TPL5111 for intervals longer than 2 hours? A: No, the maximum delay interval for the TPL5111 is 2 hours. For longer intervals, consider using a different timer solution or an external microcontroller with sleep functionality.

Q: How do I calculate the resistor value for a specific delay? A: Use the formula provided in the TPL5111 datasheet, which relates the resistor value to the desired delay time.

Q: Is it possible to change the delay interval dynamically? A: Yes, you can use a digital potentiometer or a DAC to dynamically adjust the voltage at the DELAY pin, thereby changing the delay interval.

This documentation provides a comprehensive guide to using the Adafruit TPL5111 Reset Enable Timer in your projects. For further information, consult the official datasheet and Adafruit's resources.