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Hello.

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Welcome back.

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In this lesson we shall give a brief overview of the universal asynchronous receiver transmitter otherwise

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known as the U art computers transfer data in two ways parallel and serial in parallel data transfers

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often eight or more lines or wires are used to transfer data to another device in serial communication.

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The data is sent one bit at a time in the past.

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Parallel data transfer was preferred for short distances because it's made transfer multiple bits at

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the same time and provide higher throughput.

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As technology advances the data rate of serial communications sometimes exceed parallel communication

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while parallel communication still retains the disadvantages of the size and cost of cable and connector.

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The crosstalk between the data lies and the difficulty of synchronizing the arrival time of data lies.

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Longer distances also still existed in the parallel communication you.

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Art is one of the most common serial communication protocols and in this lesson we shall explore some

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of the basics of the new art protocol the data coming in at the receiving end of the data line in a

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serial data transfer.

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Is all zeros and ones.

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It is difficult to make sense of the data unless the sender and receiver agree on a set of rules or

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a protocol on how the data is packed.

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How many bits constitute a character and when the data begins and ends a synchronous zero data communication

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like the new art is widely used for character oriented transmissions in the asynchronous method.

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Each character such as ASCII characters is packed between start and stop it.

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This is called framing their starts.

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It is always one bit but it's stopped.

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Bits can be one or two bits start but is always zero and the stop it is indicated by one for example

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over here we send into ASCII character E which has the binary number 1 0 0 0 0 1 which we'll talk about

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this other 0 later but there's a reason we have another 0 added here

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as we can see the data is framed between the start speeds and to stop it stop it.

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As we said are indicated by one and this starts it is always indicated by zero and a stop it can be

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two in number by just by the Stop it is always one you can have one bit full stop or two bits full stop.

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In this in this example we've got two bit four stop the rightmost bit or the LSP assent first the LSP

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stands for the least significant bit in asynchronous serial communications peripheral chips can be programmed

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for data that is 5 6 7 or 8 bits wide while in older systems ASCII characters where 7 bit the mode in

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systems usually send non ASCII 8 bits data as well.

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Now let's talk about parity in some systems in order to maintain data integrity that parity bits of

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the character bytes is included in the data frame.

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This means that for each character we have a single parity bit in addition to the start and stop bits.

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The parity bits may be odd or even in the case of an order parity the number of data bits including

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the parity bit has an odd number of ones.

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Similarly in an even parity the total number of bits including the parity bits is even for example the

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ASCII character a has the binary number 1 0 0 0 0 1 and with course serial included to the beginning

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here of course you added here for even parity you R2 chips allow us programming of the parity bit for

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odd even.

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And in fact we can choose not to have parity at all.

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When programming the chips and we shall see how to do this programmatically.

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Now we look at data transfer the rate of data transfer in serial data communication is stated in BP

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s or bits per second.

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Another widely used terminology for BP s is the board rate.

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However the both rate and BP s rates are not necessarily equal.

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This is due to the fact that both rate is defined as the number of signal changes per second in modems.

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It is possible for each signal to transfer multiple bits off of data but when we are talking about wired

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connections like that you add that both rate and BP s are the same.

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So this order is for this short.

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Both of you on you art and the you art data transfer protocol.

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If you have any questions just let me know.

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I'll see you later.