Questions tagged [uart]
A UART (Universal Asynchronous Receiver Transmitter) is a piece of logic that sends and receives data on a serial port.
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Difference between UART and RS-232?
Most of the time RS-232 and UART come together in serial communication theories. Are they both the same? From my readings I concluded UART is a hardware form of the RS-232 protocol. Am I correct?
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What standard UART rates are there?
I know 9600, 19200, 38400, 57600, 115200 and 1.8432 Mbaud, but no others. Why are these values used, and is it simply doubling each time or is there something more complex going on (for example, 38400 ...
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Software to create timing diagrams
In my professional life, I sometimes need to create timing diagrams for protocols: UART, SPI, etc. However, I can't find any good programs available. What programs can be recommended for this and what ...
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When should one switch from ASCII to advanced serial protocols?
All my microcontroller devices that communicate with the PC via UART use ASCII strings for sending commands and receiving data (as implemented in Arduino). That's what I learned when I began digging ...
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UART & USART - What's the difference
In the office I hear these terms thrown around as if they are the same. My understanding is that USARTs can deliver the clock signal along with the data.
Are there any other differences? What are the ...
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Pull up resistors on UART
I was going through an app-note AN2606 where I came across this connection diagram:
As per my knowledge, UART is push-pull type and Tx provides the pull-up required and hence we don't need to use any ...
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UART signal is "rounded"
I am trying to debug a UART driver for the STM32F405. It does not work above a certain baud rate (about 50 kBd). I connected it to a logic analyzer with analog capability, and I saw that the signal is ...
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Maximum cable length for 3.3V UART signals
I would like to avoid using RS-232 converters between two microcontrollers on two different boards. For various reasons, only UARTs are supported, e.g. no SPI or I2C, and I will be using CAT5E cable ...
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How does an FTDI chip work?
Someone asked me the other day how an FTDI USB to serial UART works, and I realized I didn't know. I looked at the datasheet for the FT232R and the block diagram didn't really help me. Can anyone ...
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Injecting a communication signal over DC power supply lines
I'd like to be able to daisy chain multiple devices using just the power supply wires and then inject a communications signal over the power lines to turn it into a half duplex network.
Are there any ...
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One or two UART stop bits?
UARTs often let you choose between 1, 1.5 and 2 stop bits. With 1 stop bit payload efficiency is 80% (8/10), with 2 stop bits that drops to 72.7% (8/11). So what's the advantage of the second stop bit?...
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Why are two transistors often used instead of one?
Many circuit designs I see with transistors use two transistors chained together instead of just using one transistor. Case in point:
This circuit is designed to allow a device with a 3.3V UART to ...
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How critical are UART frequencies?
I'm going to be using an 8 MHz crystal to run my microcontroller at 16 MIPS (PLL 4x, 2 cycle instructions.) However, 8 MHz doesn't divide into any UART frequencies AFAIK... so how critical are these ...
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Would it be considered good practice to match the lengths of UART's Tx/Rx traces?
I am assuming the answer would be yes since Tx/Rx pins are used to send data back and forth, or is it of such a low frequency that such thing is not required?
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USB, UART, SPI difference and usage? [closed]
I am trying to enabling an embedded system built around Intel D1000 MCU. I am mainly from a software background and just starting to catch up with some hardware knowledge.
I am trying to build ...
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