I2C Bus on the IoT Proto Shield Plus

I2C BUS on the IoT Proto Shield Plus

I2C (Inter-Integrated Circuit, eye-squared-C) is widely used for attaching peripheral ICs to processors and microcontrollers (check out more about I2C Wikipedia or other online documentation).

I2C on the IoT Proto Shield Plus is used to communicate with devices such as displays, RTC clock, etc.

I²C signals routing on the IoT Proto Shield Plus

DEFAULT CONNECTIONS

I²C signals on the IoT Proto Shield Plus are routed by default according to the following connections:

SCANNING FOR I2C DEVICES

You can use the sample sketch IoTPSP_I2C_scanner (location: IoTPSP_Sample_SketchesIoTPSP_I2C_scanner) to scan the I²C bus.

The scanner shows connected I²C devices addresses. With no external devices (such as OLED displays etc.) the scanner shows the address of the PCF8574 onboard chip (usually 0x20 or 0x38).

Using the I2C with different GPIO pins

Most of the libraries used to communicate to I2C devices, use the default I2C GPIO pins (see default connections here), thus it is NOT recommended to reroute I2C signals.
Anyway, if you want or need, follow the instructions below.
According to the above figure, I2C signals are routed to the default GPIO pins by means of JP6 and JP7.
To disconnect I2C signals from their default GPIO pins, you must OPEN JP6 and JP7 pads 1-2 (cut in the middle of pad 1 and pad 2) and CLOSE pads 2 with pad 3 (by means of a little drop of tin).
Solder a header on J41 and, by means of some jumper wires, connect other GPIO pins according to your needs.
Please check the default signal routing of the IoT Proto Shield Plus (see default connections here) to avoid conflict with other default connections.

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