Datasheet

26
BIG AVR 6 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 PG2 pin with the relevant DIP switch SW7, jumper J7 and PG2 push
button with jumper J12 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 PORTG port pins to be
connected to pull-down resistors, it is necessary
to place jumper J7 in the Down SRVLWLRQ ¿UVW
This enables any PORTG port pin to be supplied
with a logic zero (0V) in idle state over jumper J7
and 6x10k resistor network. To provide the PG2
pin with such signal, it is necessary to set switch
PG2 on the DIP switch SW7 to the ON position.
As a result, every time you press the PG2 push
button, a logic one (VCC voltage) will appear on
the PG2 pin, provided that jumper J12 is placed
in the VCC position.
In order to enable port PORTG 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 jumper J7 in the Up position
and jumper J12 in the GND position. This
enables any port PORTG input pin to be driven
high (5V) in idle state over the 10k resistor.
As a result, every time you press the PG2 push
button, a logic zero (0V) will appear on the PG2
pin, provided that the PG2 switch is set to the
ON position.
In case that jumpers J7 and J12 have the same
logic state, pressure on any button will not cause
input pins to change their logic state.
)LJXUH: Jumper J7 in pull-down and jumper J12 in pull-up position
)LJXUH Jumper J7 in pull-up and jumper J12 in pull-down position
)LJXUH Jumpers J7 and J12 in the same position