Before starting this week's assignment, some new terms had to be googled to be familar with their meaning. In addition, because the LCD from Week 9 which uses normal Serial wired communication "failed" miserably. Please refer to Week 9's page to see the struggles, I decided to buy a new LCD that uses I2C communication, since that'll be less pins to worry about.

So, what is an I2C? an I2C is an inter-integrated circuit bus, or a two-wire synchronous serial bus. But, what does that mean?

Two Wire mean that the I2C uses two wires (in addition to ground). These are serial data (SDA) and serial clock (SCL). These are wired in an open-drain configuration, which means they cannot output high logic (1), and instead only pull low (outputting 0). To make the line go high, you need a pull-up resistor between the line and positive rail in order to pull the voltage up. A good value of a pull up resistor is 1-10K ohms. There is one pull up resistor on the SCL and one on the SDA.

Synchronous means that data transfer is synchronized trough the clock signal. An asynchronous signal uses stuff like Baud Rate, instead of a clock.

Serial means that one single bit is transfrred at a time over a single wire. Parallel data has multiple wires, each carrying one bit.

Bus is a system which lets devices to communicate to each through single set of wires. So, a bus such as I2C allows new devices to be connected by simply adding their SDA and SCL connections to the existing line. Buses like I2C use addressing systems (and each device comes with a unique address. In the case of I2C they come in binary numbers).

On I2C buses, there should be children (or what are called as slaves sometimes) and masters. a Master is what starts a connection protocal, and the child/slave is what waits for the master before it sends or receives.I2C had the capability of having multiple masters, and even more, two masters, for example, can transmit at the same time! When a master requests to send from a child/slave it writes data to the bus. And when it receives, it reads the bus for any data that the child sends. The master is what provides the clock signal on SCK.

Continution of Networking, Output, and Input weeks can be found on the Final Project Page.

Download Traces of I2C LCD Circuit
Download Edges of I2C LCD Circuit

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