Understanding UART 

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Yep, that's a typo - bit pattern and diagram are correct. Thanks!

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UART will always have a special place in my heart :)

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My understanding is that a UART is included in most Bluetooth chips for the host-controller interface, with USB being another popular choice. Generally speaking, UART is often cheaper and easier to implement than other protocols but has lower data throughput. That said, the suitability and cost of using one protocol vs. another is a function of many things, so I couldn't really comment on that part of the question without knowing a lot more about the application, other components in the system, etc.

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@@pauldenisowski 😄

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(laughs) I wish I had a dollar for every person who noticed that :) You're absolutely correct - thanks!

7N1 means seven bits, no parity bit and one stop bit, whereas 8N1 means eight bits, no parity bit and one stop bit, so these settings are most likely incompatible. If one of the endpoints is a configurable terminal program (like Hyperterm, PuTTY, etc.) you should be able to configure these parameters.

1. The order of the bits (LSB or MSB) has to be agreed upon by the transmitter and receiver (and clearly must match at both ends) 2. NRZ is the most common type of line coding used 3. The transmitter and receiver must be configured to use the same baud rate, number of data bits, parity type, etc. From these two pieces of information, it is possible to derive the length of the frame (number of bits) and distinguish between a payload "1" and the stop bit.

After doing some searching, I believe the frame length is also pre-configured just like the baud rate. (Please let me know if I am wrong)

@@maxint2680 Yes, that's correct: Normally in serial communications, you have to explicitly specify (i.e. configure) certain parameters, which need to match on both ends of the connection. These are the speed (baud rate - e.g. 9600), the number of data bits (7 or 8, usually), the number of stop bits (almost always 1), and the parity type (none, even, or odd). So if you know these values, you can derive the length of the frame. If you use PuTTY as a terminal program, these values can be found under "Connection -> Serial"

@@pauldenisowski Detailed explanation. Thanks!

You are always have "start" bit for this purpose which are "0" (low level one), this is kind of something change or begin at the line.

Depends on the type of parity - even versus odd. In even parity, the number of ones in the user bits + parity bit must be even, so if you send 1 1 1 1 and are using even parity, the parity bit would be zero. If you were using odd parity, the total number of ones would need to be odd, and 1 1 1 1 would require a one as the parity bit.

In order to UART to work, but transmitter and receiver have to be configured to run at the same speed (asynchronous - no shared clock).

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I'm working on some automotive protocol presentations that should be ready later this year :)

Lol - I've had about a half dozen people catch that already :) I guess I should be happy that people are watching the video that closely. Thanks!!!

UART requires that both sides be configurated with the same bit rate and the number of data bits (this is fixed for all UART frames exchanged and cannot be "signaled"). So the receiver will know how long the frame is and thus can identify the stop bit.

Sorry, not with "standard" UART. Is there a reason why you would want a second parity (well, error-checking) bit?

Typically the user data is 8 bits long. That said, UART doesn't specify how long the payload should be. I still remember when 7-bit ASCII was the norm in serial text transmission.

Yep, must have fat-fingered that one (binary is correct). Thanks!

Actually, it's for people who can't type :) The binary is correct :)

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Si pudiera, lo haría :)

Yes, more than one stop bit is extremely rare. But I'm not sure what you mean by UART needing 3 wires - could you clarify? Thanks!

@@pauldenisowskicould be referencing a ground wire