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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59 views

How to connect STM32F103C8t6 to computer when using USART?

I'm an electrical engineering student and I've just started to learn microcontrollers.I want to know is there any way to connect my board(I uploaded its picture)to computer when I'm using USART ...
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97 views

IoT vehicle monitoring interface

Creating an IoT vehicle monitoring interface using the Arduino CAN-bus shield and the STM32L496 discovery kit to transfer the received data to cloud. What pins should be physically wired between the 2 ...
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RPI-arduino communication without UART

I'm working on a project where a raspberry pi zero will be the main controller. The pi has to receive information from a GPS module (gy-gps6mv2) over UART. The same pi will be controlling (receive and ...
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1answer
74 views

Complete synchronous USART implementation [on hold]

I've been studying about USARTs and I haven't seen a consensus on synchronous USART implementation among MCU producers. First of all, there are transmit and receiver clock lines on some serial ...
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3answers
136 views

How far can 3.3V UART go at 38400 baud?

I'm developing a set of boards that will all be listening to a single 3.3V 38400 baud UART (single TX device, my boards all listen to this line, no "RX" line). They are designed such that there are ...
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Can an SPI slave start a transmission in full-duplex mode?

As far as I know, SPI transmission for an SPI slave works like below: Master selects a slave using SS pin Master and slave send data to each other simultaneously Master starts clock and data ...
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1answer
61 views

RS-485 network with multiple masters

I'm building a project with multiple RS-485 senders ("masters") and one receiver: simulate this circuit – Schematic created using CircuitLab I'm using one MAX485 as receiver connected to a ...
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1answer
87 views

What is difference between UART and i2c [closed]

Why do we need communication protocol and what is the difference between UART and i2c other than clock?
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51 views

Programming ESP8266 in circuit

I've designed a simple WS2812B LED Controller utilizing the ATMega328p and an ESP8266 to connect to WiFi. The two are supposed to be communicating over UART. I've made a mistake of not testing the ...
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Arduino Mega to Raspberry pi 3 Uart communication stops after a short while [migrated]

I have been trying to setup a data stream from Arduino to rpi using an USB to Uart converter. I am using 4 startbytes and then reading all 36 bytes of data at once. Baudrate, parity and stopbits are ...
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1answer
45 views

Existing UART libraries on pic/atmega/

I am still new on electronics (my background is software), I played around a bit with Arduino, and I am trying to advance on other microcontrollers like PIC, ARM, etc. Can I rely on existing ...
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92 views

What kind of connector is this? It is used to connect to a device through UART

I'm searching for a 4-pin connector like the one that is displayed below to connect to a device through UART. We have received a couple of connectors from the manufacturer, but we have way more units ...
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1answer
69 views

STM32F4 and SIM800L logic level

I am currently using an STM32F401RE that I have to interface with a SIM800L GSM module via UART. In a first "toy example" I used Arduino and found no problems, but passing to the STM MCU I am unable ...
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71 views

STM32F0 programming through system bootloader using UART

I am writing a python script similar to STM32Loader that can write a hex formatted program to the flash of an STM32F0. I have managed to use the system boot-loader to write the hex file to the chip ...
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2answers
55 views

What are some good replacement ICs for DIP UARTs? [closed]

Recently, I have been developing an SBC based on the Zilog Z80 microprocessor. Since my first design, a serial connection has been essential for the board to communicate with a PC or terminal. For ...
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1answer
33 views

DIP temperature Sensor with serial port [closed]

I am looking for a temperature sensor which is in for of DIP suitable for breadboards and serial communication that is usable for Arduino. I am not after a resistive or an analogue sensor. I am not ...
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1answer
66 views

UART receive detection

I am working with UART and I want to do something but could not achieve myself. I want to enter an interrupt when the data receive stops, i.e when I unplug the cable, do something only once and then ...
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1answer
28 views

Atmega328 ubrr value shifting issue for serial transmission

My doubt is about the way in which the baudrate value is written into UBRRn registers. For eg: Lets say i want to write the value 25 into UBBRn registers to configure the microcontroller to ...
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3answers
222 views

Serial communication between STM32F4 and PC -USART-

The question I will ask now is not about how to solve something, I am currently able to make the connection as it will be mentioned below, but my problem is I really did not understand WHY ? Thanks in ...
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3answers
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Most significant Bit first Vs Least significant bit first

I am studying protocols and came across a concept of MS bit first(in I2C) and LS bit first(in UART). I couldnot understand the advantage/limitations one has over the other? on what basis is it ...
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1answer
52 views

Isolated UART communication: Which side should send the supply for the isolator?

I am in a situation to establish an isolated UART communication between two separate PCBs. The first PCB regulates and sends the required isolated power of the second one. The UART communication will ...
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1answer
53 views

Making UART between ATmega32A and the PC :

I used PL2303hx to connect my PC to the chip and I did the correct connections and installed the driver of the IC and the program I wrote was simulated succesfully on proteus: But when I do it on the ...
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2answers
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ATMEGA328 Serial input via ISR to buffer - buffer messed on printout

Using an ISR on the atmega328 to read a string ended by a \r from UART and echo back the readout string afterwards ...
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1answer
60 views

STM32F437 UART doesn't work at 3.6V~4.2V(lithium battery)

led is on but UART doesn't work when using lithium battery. stm32f437 UART can work at 5V(power supply). ...
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1answer
56 views

Can the FTDI Tx and Rx tension level be different that it's VCC?

I'm building my own FT232RL to convert a UART signal to USB. The source of power will be the USB 5V, but for reasons of the circuit i already have it would be easier to let more of the circuit keep ...
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38 views

PIC24FJ Baud Rate Issues / Crystal Selection

I'm using a PIC24FJ1024GA606 and I'm using the internal Fast RC Oscillator. Here is my config: ...
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Usart2 on STM32F401RE is not working after cutting st-link

As I know, Virtual COM port of ST-Link connection is connected to Usart2 on a STM32F401Re. When, ST-Link part is still attached everything is working fine on Usart2. However, after cutting ST-Link ...
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1answer
38 views

Atmega32u4 USB and USART

I have an ATMega32u4. My question is about the bootloader section. How does this device pretend to be a com port while connected to USB? What makes the computer think it is a com port and how can I ...
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1answer
76 views

PIC18F26J50: how to use printf in C18

I'm trying to use the printf family of functions in C18 for a PIC18F26J50. In my system, the output should go through the UART and show up in RealTerm. Here is my ...
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107 views

Number of bits after stop bit before going to idle state. Is it regulated by a industrial standard?

Does anyone know a number of bits after stop bit before going to idle state. Is there any standard on this matter (e.g. industrial)? Update: So my questions are: What marked areas stand for. What ...
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1answer
40 views

MSP432+BLE+ Debugger interfacing

I would like to Interface a BLE to a MSP432 microcontroller in serial. The BLE has a inbulit Atmel controller. I have a firmware for BLE in keil. Intially I have flashed the firmware to BLE directly ...
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37 views

MEGA2560 only starts program after pressing RESET button multiple times

I am working on a program where I am controlling an MP3 player by using UART between my MEGA2560 and the MP3 player. The MEGA2560 sends serial commands to the MP3 player when external interrupts are ...
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1answer
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PIC18F26J50 serial communications over RS485 link

I'm trying to figure out why my serial communication is not working. The design is to use the UART of a PIC18F26J50 over a RS485 link. Here is the relevant part of the schematic. Other relevant info:...
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RC filter for UART

I am working with a device. Block diagram looks like this: I was facing a noise challenge and asked a question here. I implemented the RC filter design suggested by @analogsystemsrf and got good ...
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1answer
60 views

DMA, Interrupt and UART connection in STM32 for detecting chararcters

I am trying to make a project and am planning to use DMA for my UART from one STM32 to another STM32. Here are some details of what am I using: Chip: STM32F107RB debugger and programmer: Atollic for ...
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1answer
49 views

Transmission of serial data characters

On a serial data link characters are transmitted data rate of 9600 baud. if characters are 8 bits and there is one start bit and one stop bit per character, then what is the number of characters ...
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1answer
84 views

SPI and UART of atmega32 were not working when atmega32 was interfaced with ad7705

I was trying to read 16bit ADC ad7705 by atmega32 and send the value read through SPI communication of atmega32 to real-term software by using UART of atmega32. I found that there was no transmission ...
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1answer
81 views

Protecting an IO pin from a spike

I am building a circuit which communicates with an external Power Supply via UART. One of the IO pins from my MCU is connected to an optocoupler I have 4 relays on my PCB, they are separated ...
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Is using the CH340G on a commercial product a horrible idea? [closed]

I'm developing a niche product that will be produced at a fairly low volume (low hundreds). I'm using an Atmega uC, and one of the requirements is the ability to be field-flashable by the user. My ...
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USART6 STM32F746NG isn't working

I'm having trouble configuring the USART6 in my STM32F746NG. I am setting up the USART6 to enable UART comunication, using the code below to initiate it and also create an echo function. ...
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Xbee Router in API mode not sending frames from UART input?

My current system is setup as follows: MCU ------ Xbee A(Router) ------ Xbee B(Coordinator) Xbee A is a router in API mode, Xbee B is a coordinator in API mode. MCU is MSP430, Xbee modules are ZB ...
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1answer
81 views

Distance between UART and I2C bus

I create a board with two bus: UART and I2C. Now I am expanding the connection terminal, which has the following contacts: RX / TX / SDA / SCL / + 5V / GND. The question is, do the I2C and UART buses ...
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What if we disconnect Tx and Rx at the time of code execution in UART?

I have interfaced Nodemcu and arduino using UART communication protocol. After uploading the code, When the output is seen on serial monitor,I disconneted Tx and Rx physically. still I can see the ...
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1answer
31 views

Issue with timer_func() and delay_func() in generic library for R551 Fingerprint Sensor - ATMega328p

Apologies for the long-winded question. I've recently stepped outside of the Arduino realm for hardware programming. I'm working on a project that interfaces a R551 Fingerprint Sensor with an ...
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2answers
102 views

How to choose UART maximum output speed?

When I open up a project in STM32CubeMX and configure a UART, there's a Maximum output speed configuration (under GPIO Settings) that defaults to Very High. The options are: Low Medium High Very High ...
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RS485 PCB Design

I'm currently in the process of designing PCBs for my project. There's going to be one larger control board, and 10 daughter boards. The daughter boards will measure the current/voltage of some ...
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1answer
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Level Matching Circuit

Somebody know what do this circuit exactly or how it works ? Where VDD = 5V (MCU) and VDD_1V8 = 1V8 It is a recommended circuit to use uart communication when the voltage level are not the same, I ...
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Multiple sensors on a single serial port [duplicate]

I want to use a single serial UART port on an mcu to communicate with two different sensors. I have connected both the sensors' TX lines together to mcu's RX line and vice versa. I am switching the ...
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1answer
41 views

How to avoid duplicate messages in a mesh network of mcus

I'm working on a project, where each pcb has a connector on every side, so you can connect these board in a grid. It's basically a mesh network of modules. These modules need to communicate with each ...
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0answers
42 views

Reduce wake-up noise on ARM CM3

I need some help exploring a solution. I have an ARM Cortex M3 MCU, which has low-power sleep mode implemented. Wake-up sources are any GPIO pin, or an RTC alarm. A terminal is connected to UART-0 ...