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2.6
Internal/External Clock (Jumper X6)
The clock supply of the microcontroller can be selectec by setting the
jumper X6. There are two possibilities for the controller's clock supply: The
controller can either get its clock from the 20 MHz crystal oscillator on the
AT89C5132 board (Internal Clock) or from the CLKOUT2/4 pin of the
VPC3+ on the Extension board (External Clock):
Default
Figure 2-5: Settings of Jumper X6
2.7
Display Elements
The Controller Board has three LEDs: The green LED D10 indicates correct
power supply. The red LED D9 and the yellow LED D8 are connected to
the ports P1.4 and P1.5 of the controller.
2.8
I/O Area
The I/O area consist of 3 DIP switches (Port0, Port1, Port2) and 3 LED
lines.
The data bus lines to the DIP switches are connected via pulldown resistors
to GND. If a DIP switch is OFF, the corresponding input port of the
controller is connected via pulldown resistor to GND and the controller
therefore reads a logical '0' from this DIP-switch. If the DIP-switch is ON,
the controller's input is connected to VCC via the DIP-switch and the
controller therefore reads a logical '1' on this port.
2.9
Reset Button ( S4 )
The entire application can be reseted by pressing the Reset Button S4.The
microcontroller goes into a defined state and starts up the application
program.
VPC3+S Evaluation Kit
Copyright © profichip GmbH 2009
Controller Board (AT89C5132)
External Clock
Internal Clock
(DEFAULT)
Revision 1.00
2
13
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