GPIO Pull-Up Characteristics

Figure 1. I/O Pin Pull-Up Resistor Current vs. Input Voltage (VDD = 1.8V)
Figure 2. I/O Pin Pull-Up Resistor Current vs. Input Voltage (VDD = 3.0V)
Figure 3. I/O Pin Pull-Up Resistor Current vs. Input Voltage (VDD = 5.0V)