B4R Tutorial Shift Registers (Serial In Parallel Out - Parallel In Serial Out)

hatzisn said:

This is a very useful tutorial by the guy in dronebotworkshop which opened new horizons for me since I didn't know there were two kinds of shift registers (actually four). Enjoy:

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Of course you can use this technology to implement simple port expanders. Personally I don't use them any more and I prefer MCP23017/MCP23S17 solution, because it is almost infinite regarding expansion. And no messy parallel output during register load.

tigrot said:

Of course you can use this technology to implement simple port expanders. Personally I don't use them any more and I prefer MCP23017/MCP23S17 solution, because it is almost infinite regarding expansion. And no messy parallel output during register load.

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I checked it on YouTube and components pinouts app. They are impressive. I am not familiar at all with the SPI protocol but I have some basic knowledge of the I2C. Given the 127 separate addresses a simple multiplication gives you 2032 ports. I didn't understand though if through the resisters you have access to all 127 addresses or only in the ones described in the datasheet. I suppose it is the second but after a long day my head is starting misbehaving. Nevertheless a big thank you for the knowledge you gave us all. According to your knowledge is SPI or I2C protocol faster?

There is a library for Android. https://github.com/adafruit/Adafruit-MCP23017-Arduino-Library

I think SPI is a little faster but I2C is smarter since you use only three pins instead of four(counting reset pin) and it's able to connect multiple device with different addresses. But it's an opinion