| Parola for Arduino Text effects for Parola modular hardware

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System Connections

## Connecting Parola to the Arduino

The modules are connected through a 4-wire serial interface (SPI), and devices are cascaded, with communications passed through the first device in the chain to all others. The Arduino should be connected to the IN side (shown in the figure below) of the first module in the chain.

Module Input Header

The Arduino interface is implemented with 3 digital outputs that are passed through to the class constructor. The digital outputs define the SPI interface as follows:

- DIN (MOSI) - the Data IN signal shifts data into the display module. Data is loaded into the device's internal 16-bit shift register on CLK's rising edge.
- CLK (SCK) - the CLocK signal that is used to time the data for the device.
- LD (SS) - the interface is active when LoaD signal is LOW. Serial data are loaded into the device shift register while LOAD is LOW and latched in on the rising edge.

Note that the LD signal is used to select the entire device chain. This allows separate LD outputs to control multiple Parola displays sharing the same DIN and CLK signals. The software needs to instantiate a separate object for each display.

The remaining interface pins are for +5V and GND. The power supply must be able to supply enough current for the number of connected Parola modules. The central position of the GND connector provides some protection for accidentally reversing the connector.

## Connecting Parola Modules

Separate Parola modules are connected by the plugging them together edge to edge, with the OUT side of one module plugged to the IN side of the next, as shown in the figure below.

Connecting Parola modules