Datasheet

26
Easy24-33 v6 Development System
MikroElektronika
page
Pull-up/pull-down resistors enable you to set the logic level on all microcontroller’s input pins when they are in idle state. Such level
depends on the position of the pull-up/pull-down jumper. The microcontroller’s RB8 pin with the relevant jumpers CN110 and RB8 push
button with jumper J6 are used here for the purpose of explaining the performance of pull-up/pull-down resistors. The principle of their
operation is the same as for all other microcontroller pins.
In order to enable the PORTB port pins to be
connected to pull-down resistors, it is necessary
to place jumpers CN110 in the Down position
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supplied with a logic zero (0V) in idle state over
jumpers CN110 and 8x10k resistor network.
As a result, every time you press the RB8 push
button, a logic one (3.3V) will appear on the RB8
pin, provided that jumper J6 is placed in the
VCC-3.3 position.
In order to enable port PORTB pins to be
connected to pull-up resistors and the port input
pins to be supplied with a logic zero (0), it is
necessary to place jumpers CN110 in the Up
position and jumper J6 in the GND position. This
enables any port PORTB input pin, when it is in
idle state, to be driven high (3.3V) over the 10k
resistor. As a result, every time you press the
RB8 push button, a logic zero (0V) will appear
on the RB8 pin.
In case that jumpers CN110 and J6 have the
same logic state, press on any button will not
cause input pins to change their logic state.
Figure 20-4: Jumpers CN110 in pull-down position and jumper J6 in VCC-3.3 position
)LJXUH Jumpers CN110 in pull-up and jumper J6 in GND position
)LJXUH Jumpers CN10 and J6 in the same positions