37.2.3 GPIO Pull-Up Characteristics Figure 37-29. I/O Pin Pull-Up Resistor Current vs. Input Voltage (VDD = 1.8V) Figure 37-30. I/O Pin Pull-Up Resistor Current vs. Input Voltage (VDD = 3.0V) Figure 37-31. I/O Pin Pull-Up Resistor Current vs. Input Voltage (VDD = 5.0V)