Determining the Value of the User-Provided Pull-Up Resistor
- Updated2023-03-22
- 1 minute(s) read
Complete the following steps to determine the value of the user-provided pull-up resistor:
- Place an ammeter in series with the load.
- Place a variable resistor between the digital output line and the +5 V supply.
- Set P0.0 to high.
- Adjust the variable resistor until the ammeter current reads as the intended current. The intended current must be less than 8.5 mA.
- Remove the ammeter and variable resistor from your circuit.
- Measure the resistance of the variable resistor. The measured resistance is the ideal value of the pull-up resistor.
- Select a static resistor value for your pull-up resistor that is greater than or equal to the ideal resistance.
- Reconnect the load circuit and the pull-up resistor.