Pull-up / Pull-down Resistor
Bus line in the digital circuit plays a role to transfer the data between CPU (Microcomputer), memory and peripheral devices. A resistor (pull-up and pull-down resistor) of 1 kΩ to 100 kΩ is inserted between the power supply or ground and the signal line to stabilize the signal potential of the bus line. A resistor (terminating resistor) of several 10 Ω to 100 Ω is used between the signal line and ground to match the impedance of the signal line and LSI.