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Project Notes

#190 MultiSlaveSPI

Using SPI to control multiple devices (that support an SPIish interface)

Here’s a quick video of the circuit in action:



The ShiftDriveSPI project demonstrated how hardware SPI can be used to control a system with a 74HC595 interface. The proposed benefit was that SPI allows multiple devices to be controlled with a minimal (+1) extension to the number of pins required.

This project is a test of SPI to control multiple (2) devices that support an “SPI-like” interface.

It’s interesting how far you can push the definition of “SPI-like”. In this case I’m using two devices:

These modules are all connected to the SPI interface of an Arduino, with a seperate latch (SS/slave select) for each. The data to each module actually passes down the same wire (MOSI).

The demo sketch does two things:

  • runs a 0-9 counter on the 7-segment LED module (with decimal point enabled for even numbers)
  • runs a countdown counter that cycles for each change on the LED module



The Schematic

The Build

Credits and References

About LEAP#190 SPIArduino
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This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.