MIKROE-455 mikroElektronika, MIKROE-455 Datasheet - Page 24

• Manufacturer Part Number: MIKROE-455
• Description: Development Boards & Kits - 8051 EASY8051 V6 DEVELOPMENT SYSTEM
• Manufacturer: mikroElektronika

Specifications of MIKROE-455

• Rohs: yes
• Product: Development Kits
• Tool Is For Evaluation Of: AT89S8253
• Core: 8051
• Interface Type: CAN, MMC/SD, RS-232, USB
• Operating Supply Voltage: 5 V, 9 V to 32 V
• Data Bus Width: 8 bit
• Description/function: Development Board Only, GLCD, LCD, DS1820, Serial Cable not included
• Dimensions: 265 mm x 220 mm
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• For Use With: AT89S8253

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Pull-up/pull-down resistors enable you to set the logic level on all microcontroller input pins when they are in idle state. Such level
depends on the position of the pull-up/pull-down jumper. The microcontroller pin P0.0 with the relevant DIP switch SW1, jumper J1
and push button P0.0 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 identical for all the microcontroller pins.
Figure 17-5: Jumper J1 in pull-down and jumper J6 in pull-up position
MikroElektronika
Jumper J1 in pull-up and jumper J6 in pull-down position
Jumpers J1 and J6 in the same position
In case jumpers J1 and J6 have the same logic
state, pressure on any button will not cause input
pins to change their logic state.
In order to enable the PORT0 port to be
necessary to set jumper J1 to the Down position.
This enables any port PORT0 pin to be provided
with a logic zero (0V) in idle state over jumper J1
and 8x10k resistor network. To provide the P0.0
pin with such a signal, it is necessary to set the
P0.0 switch on the DIP switch SW1 to the ON
position.
As a result, every time you press the P0.0 push
button, a logic one (VCC) will appear on the P0.0
pin, provided that jumper J6 is set to the position
referred to by VCC.
In order to enable port PORT0 pins to be
connected to pull-up resistors and port input pins
to be activated with logic zero (0), it is necessary
to set jumper J1 in position referred to as Up
and jumper J6 in position referred to as GND.
This enables any port PORT0 input pin to be
provided with a logic one (5V) in idle state over
the 10k resistor. The P0.0 switch should be set
to the ON position afterwards.
As a result, every time you press the P0.0 push
button, a logic zero (0) will apear on the P0.0
pin.
Easy8051 v6 Development System