CONNECTING DIFFERENT DEVICES TO MASTER CARD INPUTS

Let's see how to connect different device to Master card inputs. The devices we are going to use are:

• push button
• two positions switch
• three positions switch
• 12 positions rotary switch
• simulated encoder
• CTS-288 encoder with push button

In these examples we are considering the first group of inputs in J3 connector (inputs from 00 to 08).

Push button

One of the pins is connected to GND, and the other one to any free pin in the same group. In this case, input would be number 03.

Two positions switch

The central pin is connected to GND, and the pin corresponding with the ON position (see picture and colours) to any free pin in the group. In this case, input would be number 04.

 

Three positions switch

The central pin is connected to GND, and the pins corresponding with the ON positions (see picture and colours) to any free pins in the group. In this case, input would be number 04 and 07.

12 positions rotary switch

There are only 9 inputs available in each group, so this is the maximum number of positions we will be able to use in this type of switches. Anyway, there are no selectors with more than this quantity in the real plane.

The central pin is connected to GND, and the pins we are going to use (depending on the number of positions selected) to any free pins in the group. In this example, we are using three positions, inputs number 00, 02 and 04.

Simulated encoder

We can modify a 12 positions rotary encoder to simulate a encoder.

The central pin is connected to GND, and the three pins that results after the modification to three consecutive inputs in the group. In this example, inputs number 00, 01 and 02.

If the encoder behaviour is not the expected (wrong direction), we can change it by software or changing two inputs.

CTS-288 encoder with built-in push button

In this device, the group of three pins corresponds with the encoder, and the other two pins corresponds with the built-in push button.

Encoder: the central pin is connected to GND, and the other pins to two consecutives inputs in the same group. In this example, inputs are 06 and 07. If the encoder behaviour is not the expected (wrong direction), we can change it by software or changing the inputs.

Push button: we connect one of the pins to GND, and the other one to any free pin in the group (03 in the example).

Encoder and push button are totally independent, so we can use independent groups of inputs for each one. In the example both are connected to the same group of inputs.

 

Last edition: 02.06.2006