A UART (Universal Asynchronous Receiver Transmitter) is a piece of logic that sends and receives data on a serial port.

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FTDI VCCIO = 2.4V

I am using an FTDI chip for USB-UART conversion. The UART i/f on the MCU operates on 2.4V. Typically the VCCIO pin that powers the UART i/f on the FTDI IC is driven by the 3V3OUT pin [3.3V]. While the ...
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67 views

Microcontroller to PC via USB - do I need to use isolation?

I want to connect my microcontroller (dsPIC33E) to a PC via USB. Since the particular microcontroller doesn't have a built-in hardware for the USB protocol, I have to use an external chip (e.g. ...
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32 views

MCP2221 USB To UART Programmer

I am very new to the electrical design and had a very basic question. I am trying to program a Atmega328p using the MCP2221 interfacing chip. I picked this chip due to it being the only converter I ...
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68 views

Would it be worthwhile to support UART for a serial 'plug-n-play' interface? Or would it be a waste of time? [on hold]

I'm currently working on a project where I'm designing a central circuit board that will feature mini plugin circuitboards. The communication between the main circuit board and the plugin ...
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73 views

UART baud rate error tolerance

I have a question regarding the UART baud rate error tolerance, as the thread title indicates. First of all, I want to point to an excellent tutorial on clock accuracy: Maxim Integrated Tutorial I ...
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2answers
111 views

How to use UART rx data from ISR to main loop?

I am using PIC18F and currently trying to interface it with SIM900. I am using UART Rx interrupt. ISR is working correctly but I wonder how to get data in main loop. Lets say : ...
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33 views

Questions regarding using an HDMI cable to transmit SPI, I2C, and UART serial data?

I'm currently working on a design in which I need to transmit serial data over 3 different serial channels. I won't be transmitting data far (1" - 1') but I didn't want to use plain wires. Instead, I ...
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61 views

Help powering an old heater control board im trying to reprogram

Not photo of my specific board. I got 3 old universal controller board's , I'm attempting to reprogram them to learn hardware hacking. But i not quiet sure what would be the best method of powering ...
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67 views

Can't write to serial from microcontroller

I have the following items: ATMEGA328P-PU POLOLU - PGM03A (Programmer) https://www.pololu.com/docs/pdf/0J36/pololu_usb_avr_programmer.pdf So far, I've been able to write output to data pins. Now I ...
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1answer
29 views

FT231XS RX TX voltage

In the FT231XS is possible to change the rx/tx logic levels voltage? For example, change between 3.3V to 5V?
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58 views

one character is wrongly transmitted in uart communication [closed]

I am trying to interface a wifi module ESP8266 to a PIC18f4550 8-bit microcontroller with uart communication. I want to receive data from ESP8266 and show it on a LCD (2*16). The problem is that ...
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2answers
112 views

First two byte of Transmit Buffer which sent by STM32 to Motor Controller is transfered wrong

I want to use STM32F407VET6 board to send commands to Roboteq Motor Controller MDC2230 and I'm very newbie in embedded systems. Firstly, I created my project via ...
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Is this communication between 3 UARTs feasible?

I am using an MCU (STM32F0) with 3 UARTs. I would like to know if this UART arrangement is possible. Whatever is received on UART1 will be sent to UART 3 and UART 2 (after some data processing). ...
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22 views

Control of Dynamixel MX28R via RS485

I have problem controlling dynamixel MX28R servo motor. I've tested two kinds of connection. First one to raspberry Pi B+ and ...
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77 views

UART baudrate steps

I'm trying to connect 2 devices to each other based on the UART peripheral. First one support up to 1.875 Mb/s & the other one up to 1228.8 KBd. Both work correctly on the 115200 but I need more ...
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How to close a serial port (16550 UART )

Have a 16550 UART serial port on an embedded CPU based computer. It is not used in this fielded environment, however, it is possible that someone could attempt to connect to it and send data. Need ...
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23 views

Can't write to USART in PIC18F26J50

I can't write to USART in PIC18F26J50. Here is my setup: Clock is 48MHz; I'm using a RS485-driver (SN65HVD1781) in half-duplex mode. Direction PIN for this is connected to RA2; I'm using a USB to ...
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91 views

How is this RS485 Module Working?

I am planning to use this UART-to-RS485 module :- http://www.elecrow.com/uart-ttl-to-rs485-twoway-converter-p-1545.html. This module is bidirectional and uses a single pair of differential signal to ...
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26 views

How to prevent design compilation if generics are not acceptable? [duplicate]

For a UART that takes baud as generic, I want to prevent design compilation in modelsim and quartus ii if the baud rate is not in specific range. The baud rate is passed as a generic. One option is ...
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2answers
771 views

MAX232 circuit not working

I am designing a circuit using a MAX232. I have connected Tx and Rx of the MCU to the 11th &...
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62 views

Finding UART pins on a PCB header

I have a PCB with some headers exposed. I know for certain that some of those pins are UART connections (RX,TX, Ground). I'm hoping to find RS232 with TTL voltage levels but this is just an assumption....
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56 views

Surge protect RS-232

We are designing a circuit for Connecting our uC to an RFID reader via RS232 Interface. On searching for best installation practices online I found out that a surge protector is recommended as shown ...
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Indecipherable Data on Serial Monitor

I have ready made working electronic product. I am applying reverse engineering on it. The WiFi module is connected to micro-controller via UART( RX & TX). The android app sends command to WiFi ...
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1answer
53 views

Multiple UART output sensors on one serial port

I would like to connect 4 UART output sensors to one serial port of my controller. The distance between sensors and controller will be about 10m. Initially I was thinking of using 485 as physical ...
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49 views

Timer causes UART problem

I have a problem, found on both ATMEGA1284P and ATMEGA2560. I have set a 16-bit timer in CTC (tried both Timer1 and Timer5) to give an interrupt every 1ms so I can increment a 32-bit volatile time ...
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75 views

STM32 Shutting down debug session

I'm facing with a problem regarding debug session. When I start debug session, after the configuration of USART2 the debug session is closed. Keil message: Cannot access target. Shutting down ...
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93 views

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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LEDs on 3.3V serial and sd card select lines

How would i go about connecting indicator LEDs to the serial lines from my MCU(a Parallax Propeller) to a MAX3232 and the chip select line for a SD card? I want the LEDs to light up when the lines are ...
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81 views

UART works when I open minicom before starting UART

I am trying to send out large amounts of data at 115200 via UART. I have come across a rather strange problem. I am sending out data in the while loop of the MCU. The MCU is not doing anything else. I ...
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82 views

Locating serial port

I'm not sure if this is the correct stack exchange site to post this, but here goes. I have this PCB: It's from this: https://www.vasco.com/images/DP270_Xpress_april11_tcm42-47389.pdf I'm trying ...
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2answers
408 views

Using a MCU's UART as DAC

Many simple MCUs do not provide DACs despite having PWM output. For low clock frequencies like 8MHz, PWM does provide very poor quality if used for audio purposes. E.g., TI mentions in application ...
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46 views

Can USART TX on the STM32f4 be open-drain?

I'm retrofitting an old project, moving a Discovery Board from an isolated ground to a non-isolated ground, and it's shifting around all my power supplies. This will be interfacing with a 5V device ...
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STM32 starts timing out receiving data UART after reading 1 byte

I am having trouble using the UART on the STM32F103 where it stops receiving data, while not setting any of the error flags. The UART device is an ESP8266 at 115,200 baud. I am sending it ...
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52 views

STM32F107 SPI -> UART maximal transfer rate

I am designing a board with STM32F107 microcontroller and AD7680 ADC. What I need is to read data from ADC, increment sequence number after reading each sample, and send ADC values via UART or USB OTG ...
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backplane for power etherner, rs232 amd rs485?

I’m trying to build a midterm system between a costly and highly custom VPX and a platform where each board interfaces with one another by cables. for example: imagine I have an off the shelf mini-itx ...
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Allpro adapter and Arduino - UART

I couldn't find for allpro obd uart if the RX pin should receive 3.3v or 5v from Arduino TX pin (since the Arduino will send 5v by default without voltage divider), so I was wondering if someone can ...
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Sim900A Breakout board is not working

I'm using sim900A breakout board. It has UART interface with it.I'm trying to interface with PC. Module has 8 pins. Vcc,DTR,TX,RX,MIC+,MIC-,Speaker+,Speaker-,GND pins respectively. Here I have two ...
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38 views

LPC1769 PC Communication

I am using LPC1769 micro controller and planning to use one of its serial (UART) port for PC communication. It has 4 UART ports (UART0,1,2 and 3) For PC communication purpose, can I use all ports or ...
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FTDI chip stops working when sending 255

I built a simple DMX interface with these instructions. However, sometimes after a few minutes it stops working, the LED stops blinking and no more data is sent. It will only work again after ...
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UART baudrate issues on STM32F0xx board

I'm using STM32F0xx board for project. In this board there are two UART interfaces. UART1 is supporting upto 115200 baudrate and more than that, but UART2 is supporting upto only 38400 baudrate. If I ...
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3answers
55 views

Enabling RS485 UART driver and receiver at the same time

I am a software engineer so I hope that my question not stupid: I work on board with an half-duplex RS485 transceiver. From the software, I can handle a GPIO to handle the output driver of the ...
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73 views

AVR interrupt setup seems to stop program execution

On ATMEGA168PA I have problems with interrupt-driven character reception over UART. When I include the line setup_interrupt() it seems that program execution stops ...
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4answers
125 views

Are CTS and RTS necessary on UART port?

I am currently working on a project where we use TIVA C TM4C123G and I am currently getting inspired by launchpad as reference design. I have several UART peripheral to connect to the main chip using ...
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2answers
86 views

Difference between buffer and mailbox

Peripherals in Micro-controllers usually provide a way for us to send and receive data from it. Usually this are memory mapped registers. I have come across few terminologies. The most often used one ...
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101 views

pic24 UART receive data is invalid

Hello i m writng a program for UART receive interrupt for PIC24FJ64GA306 i m receiving a data which is in format of 0xAAXXXXXXXX, where data after AA can be anything... the data transmityted through ...
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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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ESP8266 not responding with CP2102

I connected my esp8266 with USB to TTL CP2102 as follows: ...
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AVR ATmega32 UART Not Reciving

I'm trying simple UART transaction functions for ATmega32. I can send the bytes but not receiving anything. I am using polled UART receive. ...
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136 views

Using libnfc with Raspberry Pi and PN532 board?

I am trying to use a PN532 Board (NFC Reader) with Raspberry Pi. I am using the ITEAD PN532 Board. First of all I connected a FTDI cable to the board. I followed these steps to install libnfc: ...
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58 views

2 UART connected on the same port

I am curently working on a project where a MCU got only one UART port available, however I need to run two peripherals with UART interface (not simultaneously) so I was wondering if I can connect two ...