How many wires does I2C need?
2 wires
I2C is incredibly popular because it uses only 2 wires, and like we said, multiple devices can share those wires, making it a great way to connect tons of sensors, drivers, expanders, without using all the microcontroller pins.
Which protocol is used for long distance communication?
Cellular. The cellular network has been in use since the last 2 decades and comprises of GSM/GPRS/EDGE(2G)/UMTS or HSPA(3G)/LTE(4G) communication protocols. This protocol is generally used for long-distance communications. The data can be sent of large size and with high speeds compared to other technologies.
Where to run I2C signals in a ribbon cable?
In ribbon cables, the I2C signals should only be adjacent to power or GND wires. The length of the cable does normally not affect the amplitude of the crosstalk very much. (As long as the cable is long enough so that the cable capacitance dominates over other bus capacitances.)
What are the capacitances of an I2C signal?
Model of the cable with I2C signals on adjacent wires. R1 and R2 are the I2C pull-up resistors. C1-C4 are the capacitances between adjacent wires in the cable while C5 and C6 are the capacitances between the diagonal wires. C7 and C8 are stray capacitances on the PCBs as well as capacitances at the pins of the ICs.
How much crosstalk is there between I2C signals?
Crosstalk between I2C signals. 2.7 m of cable, signals on diagonal wires, 2.2 kohm pull-up. Yellow signal is SCL and blue is SDA. As expected, the amplitude of the crosstalk has remained essentially the same while the edges are less steep due to the added capacitance.
Which is a valid high logic level for I2C?
The I2C specification defines valid high logic levels as being at least 70% of VDD. 70% of 3.3 V is 2.31 V and the glitches in the plot above dip down to this level, which is bad. The mechanism for coupling from the disturbing signal (the aggressor) to the disturbed signal (the victim) is the capacitance between the wires in the cable.