Hardware description and configuration
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## Hardware description and configuration

### Connections

PARPORT

  Connect this to the PCs parallel port (IEEE 1284). You find the pin configuration of that port at http://en.wikipedia.org/wiki/Parallel_port#Pinouts.

ANALYZE

  This connector is used to connect the 8 data lines to a schematic (e. g. a I˛C bus or a RS-232 line). You have to connect GND and between one and eight data lines.

  The first two pins (number 1 and 2) can be connected to a 5 V logic (TTL level) or to a +/- 12 V (RS-232) logic depending on the jumper settings (see Jumpers). The other pins (3 to 8) can only be connected to a 5 V logic.

9V-IN

  This is the power supply for the board. We use an external power supply instead of using a pin of the parallel port because the parallel port is not designed to provide current for devices and this solution only may work with the 74HC245N IC but not with the MAX232.

  Connect this to a 9 V battery or power supply unit. The 9 V are not critical, you can also use 12 V. Refer to the datasheet of the 7805 IC for the accurate range.

### Jumpers

The hardware (as described in Building the hardware) has follwing jumpers:

JP-POWER

  Use this jumper to power-off or power-on the circuit.

JP-SER-1-DIS

  If this jumper is connected, the input pin 1 can be used as 5 V input. If it is disconnected, it may be used for +/- 12 V. Important: If JP-SER-1-DIS is connected, JS-SER1-EN1 and JS-SER1-EN2 must be disconnected.

JS-SER1-EN1 and JS-SER1-EN2

  If these jumpers are connected, the input pin 1 can be used as +/- 12 V input. If they are disconnected, it may be used for 5 V. Important: If JS-SER1-EN1 and JS-SER1-EN2 are connected, JP-SER-1-DIS must be disconnected.

JP-SER-2-DIS

  If this jumper is connected, the input pin 2 can be used as 5 V input. If it is disconnected, it may be used for +/- 12 V. Important: If JP-SER-2-DIS is connected, JS-SER2-EN1 and JS-SER2-EN2 must be disconnected.

JS-SER2-EN1 and JS-SER2-EN2

  If these jumpers are connected, the input pin 2 can be used as +/- 12 V input. If they are disconnected, it may be used for 5 V. Important: If JS-SER2-EN1 and JS-SER2-EN2 are connected, JP-SER-2-DIS must be disconnected.

### LEDs

LED-POWER

  If the LED lights, the circuit is connected with power.

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