Questions tagged [uart]

A UART is a Universal Asynchronous Receiver/Transmitter. This refers to the "hardware" serial port in the processor. Use this tag for questions about hardware serial.

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How does a callback function get revoke itself eg. Connect function get revoked when there is new connection

Further to my previous question here Can anyone help me understand how the callback function gets revoked itself? The connect function, disconnect function. BLE custom UUID code source here Another ...
-1 votes
1 answer
64 views

Trouble connecting barcode scanner to ESP32 devkit using UART - fails to connect over serial

I'm having trouble connecting a SparkFun 2D Barcode Scanner Breakout (effectively a DE2120) to a 30-pin ESP32 dev kit v1 (marked ESP-WROOM-32) and running the SerialScan sample application for this ...
-1 votes
2 answers
134 views

Send HEX number over serial

I have a RS232 device that I am able to communicate with using RealTerm on a windows PC. The device is expecting a hex string like AA BB 03 01 03 EE How would I send the equivalent string from an ...
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Can read Serial but cannot write - serial communication Arduino Mega 2560 clone

I am having issues using the following USB to UART module. I am using an Arduino 2560 clone. I have two connections with the Arduino: COM7 which consists of the given module, connected to the main ...
-1 votes
1 answer
196 views

SIM800L not responding to AT commands

I am using SIM800L module the module. I am new to GSM modules, so I've searched for the basic to use the GSM with the Arduino. this is my code. #include <SoftwareSerial.h> SoftwareSerial ...
0 votes
1 answer
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CH340G based USB to UART adapter - Pinouts - Can't find schematics

This is the board I will be referring to. There are different variations of it (with built in buttons etc.) but they all seem to be based on the CH340 chip. My problem is, that I do not know what the ...
1 vote
1 answer
76 views

Weird SoftwareSerial behaviour with Arduino nano when multiple SoftwareSerial objects are configured

So I have been stuck with this for quite some days now and am really unable to put my finger on what's wrong here. Any help would be great. Try not to list down the disadvantages of SoftwareSerial, I ...
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2 votes
2 answers
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Trying to understand the bottleneck of sensor sampling rate

Lets say I have a sensor connected to Arduino Uno Rev3's I2C Bus. I am reading the sensor output and using Serial.print() to send the sensor reading back to a my laptop. I am trying to understand the ...
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1 answer
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Using arduino framework how many instances of SoftwareSerial can use simultaneously with esp32

Ussing popular library https://github.com/plerup/espsoftwareserial/ can I have multiple softwareSerial ports (for example 6 ports). I’m the readme say “ several instances can be active at the same ...
1 vote
1 answer
238 views

Arduino Nano and ESP32 Read Different Values over Serial

I am trying to use the Neato xv11 lidar with an ESP32. This should output packets of 22 bytes with the starting byte 0xFA. The communication is 8N1 and the baud rate is 115200. When I connect the ...
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2 answers
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Serial communication with 2 Arduinos and one optocoupler

I just started working with Arduinos on Tinkercad in a school assignment and have non preexisting electrical knowledge. Tried to read up on the subject and I think I've gotten some of the facts ...
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-1 votes
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UART connected device communication only works one way

As the title implies, I have two Arduino devices (Uno and Mega) connected to each other over UART (the Mega is hardware UART, the Uno is software UART); I need the Mega to send a command to the Uno, ...
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SoftwareSerial fails to receive on Nano but works with Uno [duplicate]

I have built a circuit board that includes a BLE module and an oxygen sensor that has a UART. Writing arbitrary data to the BLE works fine, but for some reason every configuration of SoftwareSerial I ...
0 votes
2 answers
172 views

Serial comm UART1 works on Arduino but makes ESP32 continuously reboot

This comm sketch simply read incoming bytes from the UART 1 where a device is attached. It works normally on a real Arduino device. But on ESP32, it makes it continuously reboot with the following ...
2 votes
1 answer
87 views

So many missed bytes with serial comm

I have a setup with serial comm from Raspberry Pi to Arduino. It's communicating at baud 9600 on both devices, and from Raspberry Pi 3b+ GPIO-14,UART0,TX0 to Arduino Nano RX0. There's a level shifter ...
3 votes
4 answers
1k views

Bi-directional UART communication on single data wire, possible?

The nano is inside of the house, and the pro mini is outside of the house. I want to send/receive text between them. The communication will be always nano sending text to mini, and then mini sending ...
2 votes
0 answers
232 views

How to know if GPS module is dead?

I can't make function the NEO-6M-0-001 GPS module, this is the third one that already bought! I'm using an ATmega2560 as microcontroller for obtaining the data from the module and seems that the ...
1 vote
0 answers
40 views

configuring characteristics to communicate data on the Arduino bluetooth low enegy module

I have the HM-10 Arduino BLE module. I am also building an app to send and read characteristics on the BLE module. On the Arduino BLE side of things though, how do I set up which characteristic ...
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0 answers
23 views

Prevent timeout while exchange data between two stm32

I am trying to exchange data (str data) between two STM32 throughout Lora connectivity. Both STM32 has a lora module and the connection between them is working fine. Based on two functions: ...
2 votes
0 answers
47 views

receives 0 0 instead of "hello"

I receive the following: 09:27:10.618 -> 0 0 09:27:12.589 -> 0 0 09:27:14.616 -> 0 0 09:27:16.622 -> 0 0 09:27:18.576 -> 0 0 09:27:20.577 -> 0 0 09:27:22.583 -> 0 0 09:27:...
1 vote
1 answer
79 views

Need HELP!! Serial communication has a very "Strange Problem"

I am working on building a serial command receiver. The idea is came from the boot loader. However, I got a very strange problem that I have no idea what could cause it. As the first screenshot show, ...
1 vote
0 answers
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Receiving code between atmega328P (C) and Feather m0 (Arduino)

I've tried to create a receiver code for receiving my data (really only want the ac/gy values and nothing else) and use the following main code for sending via C programming: https://github.com/...
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0 answers
131 views

Send Multiple Sensors Data into single Packet in Arduino

I have two sensors data in packet but now I want to send these two sensors data into single packet in which these two sensors data are gathered. I mean I want to have a packet in which I have oxygen, ...
1 vote
1 answer
59 views

Arduino Mega reading from external sensor Issue

I have one external sensor and I want it to be connected with Arduino. The sensor came up with a usb cable and the pin out diagram is also given in the data sheet . When I simply connect the the cabe ...
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1 vote
1 answer
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Arduino , python , pyfirmata , standard firmata

Is there a way to change arduino analog reference to EXTERNAL IN PYTHON using pyfirmata or any other library ? Necessary Links : https://www.arduino.cc/reference/en/language/functions/analog-io/...
0 votes
2 answers
559 views

ESP8266: Interfacing MAX485 TTL-to-RS485 on serial port

I am using the ESP8266 NODEMCU. I am aware that the CH341 on the NodeMCU is bridged to the serial pins GPIO3(Rx) and GPIO1(Tx). Hence, any data send on Rx and Tx is also visible on the serial monitor. ...
1 vote
1 answer
708 views

Problems with Hardware Serial (UART) on Nano 33 BLE Sense

my new Nano 33 BLE Sense arrived today. I'm working on a project to send data from the the Nano via an Xbee S2C module to a receiver module connected to a Nano 33 IoT. I had the project working ...
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3 votes
1 answer
983 views

When it comes to UART to RS485 communication, what is the difference between the 'MAX485' and the 'HW-0519' module?

I recently found this model with the ID 'HW-0519' on it. It can be found online (HW-0519 in Aliexpress) and is sold for the purpose of converting UART to RS485 communication using Arduino devices. The ...
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HC-05 bluetooth module short range

I have started learning about arduino and just bought a bluetooth module, HC-05. From where i bought, it says it has range of approx.10 meters. I made hc-05 connection with arduino in below described ...
1 vote
0 answers
72 views

Trouble using bluetooth module with the ESP32s2 feather board

I am trying to use an ESP32-S2 feather board with a separate bluetooth module, the Adafruit BLuefruit LE UART Friend. I previously used this bluetooth module with the Feather M0 Adalogger through UART ...
1 vote
0 answers
29 views

Multiple arduino slaves with one master computer that sends instructions for the actuators to work

I am in the middle of an automation project and suddenly after completing one stage of my assembly, I now need to scale it. So my computer which until now was sending data to only one arduino UNO can ...
0 votes
1 answer
127 views

UART between arduino UNO and pc via USB not in sync

I connected my arduino uno to my system and then using serial tried writing and reading data but there is a problem which I found when I tried giving arduino crafted messages. My arduino code is ...
1 vote
0 answers
91 views

How can I use GPIO pins on an esp12e UART?

I've bought an esp12e UART that unfortunately had some issues, but I was able to fix them. This is how I connected it to the arduino. With this setup, I was able to host a simple web server and it ...
2 votes
1 answer
177 views

ESP send string to Arduino

I'm trying to send a string from an ESP32 to an Arduino. I'm using a level shifter, where the Uno is now the Mega (since I couldn't get the Uno to work). RX0 is now RX1, connected to UART2 of ESP32. /...
3 votes
2 answers
983 views

How to upload code without closing puTTY

My question is quite simple: can you, somehow, upload Arduino code without closing puTTY's serial console? I hate having to close the program to open it again for reading the incoming information.
-1 votes
1 answer
158 views

Set TX, RX to LOW before sleeping, re-enable uart after waking up

I have an ATmega1284p and I need to have the TXD0 (i.e. pin 9) set to LOW, before going to sleep. After waking up, I want to restore UART0 communication to work as expected. Here is my code: Serial....
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3 votes
1 answer
3k views

I2C communication between Arduino Uno and Nodemcu32-s (ESP32)

I want to send data between an ESP-32 (NODEMCU-32S) and an Arduino Uno but I haven't found any source on how to do that, so I tried this code: ESP-32 code: #include <Wire.h> void setup() { ...
2 votes
2 answers
2k views

Best buffering practice for continuous SD card writing

In a simplified example, I have a microcontroller functioning as a data acquisition device - sensor data is received over UART, and then saved to an SD card. This received data is in the form of a 12 ...
1 vote
1 answer
336 views

Serial communication between nodemcu and Arduino Uno

For the last days, I am trying to establish serial communication between nodemcu and Arduino Uno but I failed to do this. Currently, I am working on a Home Automation project. I receive data from ...
1 vote
1 answer
47 views

Is it possible my ATMega is burnt due to bad wiring?

While working on a project I tried sending data from my Arduino NANO to ATMega64 placed on AREXX Robot arm PCB via TXD/RXD. After plugging in VCC, GND, TXD and RXD to UART socket it didn't work so I ...
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Is it possible to configure uboot without the "Yun Serial Terminal" sketch by using the hardware serial on pins 0 and 1 instead?

Trying to rescue a Yun with the 1.5.3 image. It's not possible to upload the required "Yun Serial Terminal" sketch because the device hangs at U-Boot (hence the rescue attempt). Using putty ...
1 vote
1 answer
166 views

Serial.print skips or hangs inside a "if" statement. Trying to call a function VIA serial uart

I have two microcontrollers talking to each other using serial UART pins. Now for some reason which I can not figure out why... doing a Serial.print() does not work in an "if" statement. And ...
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1 vote
1 answer
131 views

Standalone ATmega328P stops responding when RX is connected

I have followed this demo and have set up a standalone ATmega328P being programmed from a Raspberry Pi via the SPI lines. I have also added a 16 MHz crystal with 22 pF capacitors, as well as I have ...
2 votes
2 answers
563 views

Am I at the limit of UART transmission time?

I'm currently using an STM32F103C8 (With an arduino core) to read 4 sensors at 1kHz, then send that data via UART (at 115200 baud) to another device. Each sensor returns a float, I also include an ...
0 votes
1 answer
895 views

Using TX/RX serial pins to communicate over USB

I'm using an Arduino Nano with an Atmega 328p. I would like to attach and use a different USB port instead of the builtin one for supplying power, serial debugging and uploading code. Currently my ...
1 vote
0 answers
136 views

Use serial communication on Sparkfun SAMD21 mini board

I am working on an economic module to be able to use serial communication with the Sparkfun SAMD21 mini development card. And I have one, the DTR (of my CH340G) do I have to connect it to the reset of ...
1 vote
2 answers
207 views

Why does controlling power with a transistor interfere with MHZ19B's serial communication?

I've been trying to turn off an MHZ19B (datasheet and teardown photos: revspace.nl/MH-Z19B). I've used an Arduino, NPN, PNP transistors and mosfets as well as the diagram below for connecting the ...
1 vote
1 answer
840 views

How to upload a sketch to an atmega328 via FTDI FT232RL UART and Arduino IDE?

I have a sparkfun AVR Pocket Programmer and have burned the bootloader and uploaded programs using "upload using programmer" via USBtinyISP. It works fantastic. I have a sparkfun FTDI Basic (...
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What NRF24L01 module is this?

I received my NRF24L01 Module today but I'm having a hard time finding any resources about this particular combination of modules! https://imgur.com/a/HrzpvdR I tried searching up the v200 1812A but ...
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2 votes
1 answer
168 views

Reset a UART connection on a Due

I have a system that involves an Arduino Due connected to a Raspi 4 through UART in which the Due sends a heartbeat signal over UART for the pi to receive and send back as confirmation. One of the ...

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