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→What do the numbers in the boxes mean?
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===What do the numbers in the boxes mean?===
===What do the numbers in the boxes mean?===
+It depends. The zynthian distinguishes between the various ways it can examine pins by adding 100 to the number.
+Connected straight to the Raspberry Pi GPIO pins are in the range 0 - 99 whilst devices using the I2C connection and an MCP23017 start at 100 and go up from there.
+In the first case you are specifically identifying the Pi GPIO pins connected to the encoders, in the second you are identifying the pins on the MCP23017 chip that are connected to the encoders and also describing how the I2C bus is connected to the Pi.
+
+====I2C====
+
+Simply, a recognised and agreed way to connect electronic devices together with an agreed set of rules about behaviour and a mechanism for informing the community there is a message to be transferred.
+It is a standard supported by both the Raspberry Pi and a range of specific IC's that do various useful things.
+
+====MCP23017====
+A chip that manages 16 Input Output Pins via an I2C connection. There are also two Interrupt lines that allow the MCP23017 to inform the Pi that a change has occurred.
+
=====Addressing=====
=====Addressing=====