Questions tagged [uart]

a Universal Asynchronous Receiver/Transmitter, better known as serial port

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Which UART can I use to send character to Raspberry Pi during boot process?

I am using Raspberry Pi 3 model B and Raspberry Pi 4 model B. I connect 3 pins: GND, GPIO14 (UART_TX) and GPIO15 (UART_RX) with my PC and use Minicom to display the boot message. However, I can not ...
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When is the 'disable-bt' dtoverlay necessary?

I have a Pi 3B+. There are a number of resources out there that suggest it is necessary to enable the disable-bt overlay in order to make use of the serial UART on GPIO 14 & 15. E.g., this ...
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How to display data from uart on raspberry pi 4

I have problem with receiving data from the raspberry pi 4 uart (ttyS0). I have ADC converter, which returns me hexadecimal string with data. The Przemytnik class is for connecting c++ language with ...
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How to disable sysrq on UART

I am trying to talk to a device over serial (ttyAMA0 or serial0) and it works, but sometimes I get the following TX from my rpi4, which crashes the device I talk to: [22763.820857] sysrq: HELP : ...
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RPi Pico: Is it dangerous to set GPIO drive strength of 12mA on all the UART-related pins

I'm working on a project with the RPi Pico that makes use of both the UARTs and has two LEDs attached to other random-ish GPIO pins. The LEDs will probably be turned on for the majority of time that ...
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GNSS module do not working with raspberry pi, but working on pc

I have an error with my GNSS module. I use it with an usb-uart driver, and when I connect it to my computer, and read datas with u-center or in a python script I get continously updated position ...
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Test functionality of a PL2303 USB-to-UART converter

I want to connect my computer to my raspberry pi (Model 3 A+) via serial console. Here is what I did (following the setup instructions described here): In the Raspbian OS enable serial in the ...
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UART Issues without USB Power

I'm experiencing an issue with UART communication when I attempt to power the RPi over the 5V pin instead of the USB port. Here's a rudimentary look at my setup: RPi 3B -> Teensy 4.1 GND -> GND +...
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Redirect U-Boot console to UART2 in RPi 4B

This is similar to this question, but for different hardware and with some things already tried. My ultimate goal is to have bluetooth on UART0 and debug on UART2. I use RPi 4B and need to redirect U-...
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Raspberry PI Serial Data Inconsistent

So I'm working on a GPS system which uses the UART on the Raspberry Pi to communicate with. Ths GPS Im using is a GNSS CLICK 7 from Mikroe combinded with the Pi 2. I have these commands run on startup,...
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Raspberry PI 4B [ Hardware FLow Control Failed ]

We were trying to Enable the Hardware Flow Control , but it's still causing problems for us in Raspberry Pi 4B. we tried 5 different methods to enable the flow control at Rpi 4B as follows : Method-1 :...
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What kind of JST connectors are needed for the Raspberry Pi 5?

All of the documentation I can find for the new JST headers on the Raspberry Pi 5 fails to mention which series of JST connectors it uses. If I want to make up my own 4-pin PWM fan, 3-pin UART or 2-...
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Code hangs when receiveing data on UART using Gpio 15(RX)

I enabled the UART interface inside the /boot/config.txt file. I know I have correctly selected the serial port because ser.write(data_to_send.encode()) gets executed successfully. The line where my ...
Osama Khalid's user avatar
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How to enable serial communication on Pi 4 using BookWorm OS?

Raspberry Pi 4 and Latest Raspbian Bookworm OS. I want to have Pi 4 communicate over serial connection using GPIO14 (BCM) and GPIO15 (BCM) or UART TX and UART RX. I have followed the same setups that ...
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Where does Pico micropython print go with main.py?

If you load a main.py file onto the Pico with micropython firmware running, it will run on startup. I can tell that this is working because I observe GPIO outputs changing, etc. However, I'm not sure ...
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No output from /dev/serial0 (RPI 4) [duplicate]

I am also doing similar project with raspberry pi 4 (bullseye version) and neo 6m module. I have followed all the steps given in https://sparklers-the-makers.github.io/blog/robotics/use-neo-6m-module-...
Shailesh's user avatar
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Unable to use my SIM900A Mini GSM module with my Raspberry Pi 3 B

I'm trying to connect my Raspberry Pi 3B with my SIM 900A Mini GSM module ( https://acoptex.com/wp/wp-content/uploads/2019/12/SIM900Apro3.jpg ). I'm facing the following issues ( maybe they are ...
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Connecting SIM800A to Raspberry Pi Zero WH with RS232

I'm trying to set up a very simple mobile proxy server using a Raspberry Pi Zero WH and a SIM800A GSM Module. The particular module I seem to have has an RS232 port as well as described in the picture....
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Failing to remap UART pins on RPi 4 - but maybe close?

Firstly, I'm floundering and out of my depth, like a blind man in a dark room looking for a black cat that really isn't there. I've been going around in circles all day with this and have had to admit ...
Natator's user avatar
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Using USB port as serial UART

So I have a circuit board (IWR6843ISK) that I want to connect to RPI400 via USB serial to send and receive data. Here are some details: This board uses a USB to dual UART bridge (micro USB port). I'...
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How to receive data longer than 32bytes through PICO UART?

I have wrote a code to process data received in a PICO from Raspi PI. I have a slider which sends number to the PICO(through UART) to set some values. If the slider is dragged slowly or clicked the ...
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Transmitting Serial data via Wi-Fi from Raspberry Pi to Wi-Fi Module

I previously built two separate projects for sending/receiving data between an Arduino and a Raspberry Pi 3. One transmitted via Bluetooth (HC-05 Module on the Arduino-side to the built-in BT module ...
JoeBro391's user avatar
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Pi4 enable uart4 without using boot/config.txt

I need to be able to enable uart4 on a Pi4 using dtoverlay, without adding it to /boot/config.txt, and have /dev/ttyAMA2 available immediately. The dtoverlay part is easy, sudo dtoverlay uart4, but /...
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Bluetooth and UART raspberry pi zero w

My objective is to get both data from VN200 GNSS/INS sensor (using GPIO14/15) and heart rate monitor strap Polar H10 (using Bluetooth) at the same time for synchronization. Bluetooth on pi zero w by ...
CoffeePlease's user avatar
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TF03 LiDar Distance Sensor UART Issues with Pico

I'm having issues getting a pico to receive data from a Benewake TF03 Rangefinder LiDar distance sensor. The User guide/Documentation mentions it working from 5-24V and it uses low voltage (3.3V) TTL ...
Isaac Flaum's user avatar
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How to Access Terminal Over Serial Port in Raspberry pi 4

I'm trying to Read and Write over Serial Port to Terminal in Headless Linux That I Installed on my Rpi4. is That even Possible? is so, how?
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RPi 3B+ & Yocto & U-Boot : free UART pins to be available for a RS232/485 HAT

I have the following hardware/software setup: Sferalabs StratoPi Base (Raspberry Pi 3B+ with a HAT for RS232/485) Distro built with Yocto and meta-raspberrypi on thud branch U-Boot SysVinit I want ...
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Pi Zero V1.3 miniuart not working

Ive got a bare metal project that has been running on Pi 3 without problems, i want to start moving it over to the Pi Zero, i have a V1.3 Pi Zero (not W) here so started with that. Ive stripped it ...
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Buffer size for /dev/ttyS0 in python

I got a Raspberry Pi 4 processing Lidar data (RPLIDAR S2) with python (PySerial library). The lidar sends data in chunks of about 50-60 bytes at 1000000 bps over serial. When I use a USB Serial FTDI ...
Petr Osipov's user avatar
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318 views

UART3 RX/TX mode doesn't work for Raspberry Pi Compute Module 4!

I am using Raspberry Pi Compute Module 4: Linux raspberrypi 5.15.82-v7l+ #1605 SMP Thu Dec 8 15:21:38 GMT 2022 armv7l GNU/Linux # lsb_release -a No LSB modules are available. Distributor ID: Raspbian ...
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Waveshare 2CH RS232 HAT on Raspberry pi 4 not sending nor receiving message

Hi Raspberry pi enthusiast, Recently i'm using 2 Channel RS232 Hat from waveshare placed on top of raspberry pi 4. And i already follow all the instruction on this waveshare's wiki. but, until right ...
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Can I use the HAT eeprom pins as a uart?

I have a Pi 4B and I want to use the HAT EEPROM I2C pins for the uart 4 that is behind them. This is a board just for me and all my other uart locations are in use. How do I disable the EEPROM scan ...
confused's user avatar
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Is this an acceptable way to set the rx/tx pins for uart1?

I'm on a Raspberry Pi Zero 2 W. Let's say I invoke this command. sudo dtoverlay uart1 txd1_pin=16 rxd1_pin=20 Does this then mean I can use those two pins via /dev/serial1? $ raspi-gpio get | grep -i ...
Eric Johnson's user avatar
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2 answers
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Is this an effective way to test GPIO 15?

I'm working with a Raspberry Pi Zero 2 W running Linux raspberrypi 5.15.61-v7+. Is this a reliable way to establish that I have a non functional GPIO 15? First, I establish that my test mechanism ...
Eric Johnson's user avatar
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622 views

UART (not the board itself) stopped working after connecting 5V to GND, can it be recovered?

I accidentally connected UART wires one row lower than it should be (see image): then I unplugged them shortly after that and then connected correctly, but serial console doesn't work anymore. USB ...
aryndin's user avatar
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Can't get the correct serial response between Raspberrypi 4 and Pico

I'm trying to make a little connection between both my Raspberry pi 4 and my Pico. Everything was ok until the pico suddenly stoped recieving what I'm sending from the Raspberrypi. Expected Outcome I ...
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Rpi Pico receiving on multiple UARTs

Expected behavior: in hardware I connect UART of a number 0/1 to the correct Pin numbers tx/rx and get it based on that connection Actual behavior: in hardware I connected UART of a number 0/1 to the ...
mr.xed's user avatar
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2 votes
3 answers
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UART usage with Ubuntu PI3 Model B

Can someone tell me the steps what I need to do tu get a serial communication to work? I have a raspberry pi 3 model b rev 1.1 with Ubuntu Server 20.04. I need to communicate with a sensor via serial ...
praetorianer777's user avatar
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RPi 2 GPIO UART can send data to Teensy, but can't receive

I am trying to send data between RPi 2 (model B) and Teensy 3.2 using the GPIO on the Pi (GPIO 14 and 15) and Serial2 on the Teensy (pins 9 and 10). The problem is, I can only send data from the Pi to ...
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raspberry pi voltage rs-232 (uart)

I am trying to configure a sensor with serial communication (raspberry-sensor). But i have connected my sensor to a oscilloscope see photo. I don't know if i can connect it directly to my rspberry pin ...
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Different UART behavior between ttyS0 and ttyAMA0

I'm using serial to communicate with this board (Serial-CAN-Board) on a RPi4. UART is enabled with enable_uart=1 Console over serial has been disabled with raspi-config and I am using SSH over ...
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using serial port ttyAMA0 as primary port for rs485/modbus; permissions blocked

I cannot open /dev/serial0. I selected "turn on serial port" and "do not run a console on serial port" in raspi-config. The /boot/config.txt contains no reference to "console&...
William Garber's user avatar
1 vote
1 answer
595 views

Raspberry pi 4, UART4 and SPI0

Raspberry pi 4 has 4 usable uart ports, uart 4 with rx in gpio 9 and tx in gpio 8, share rx pin with SPI0 miso0 pin. I would like to use both peripherals no ate the same time, but in different moment ...
Jefferson Alexis's user avatar
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392 views

Having issues interfacing SPS30 with Pico

I am trying to interface SPS30 via UART, but I am not able to start the fan. I am getting some response but it won't match any possible response from the datasheet. Using Micropython. Below is the ...
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raspberry pi zero 2 w: use PL011 UART and log on to linux over wifi simultaneously

Here is what I am trying to do: log on to linux running on a raspberry pi zero 2 W. But I also want to use the "real" UART PL011 (NOT the mini uart) for RS485 (modbus) at the same time. On ...
William Garber's user avatar
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(Pico) USB serial connection having noise?

I'm having some trouble trying to make a simple USB IO demo to test the Pico. Apparently, the USB serial connection seems to be noisy, and always puts something into the UART buffer even though I am ...
Francisco Ayrolo's user avatar
1 vote
1 answer
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Connect several sim800l with external power supply to the uart of ip4 and floating ground

I am creating a circuit with several sim00l connected to different UARTs each with its own external power. But I'm curious if having other objects like cooler-fan connected to other GND of the rpi ...
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Why does Pi Pico duplicate and mix-up characters received over UART when programmed in C?

I have a Raspberry Pi Pico whose Tx and Rx pins are wired to the Rx and Tx pins of a Wemos D1 Mini development board. The Wemos and the Pico are powered via an external 5V power supply (common ground)....
straits's user avatar
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How to use Raspberry Pi 4 with an USB to RS232 adapter cable over the serial port

I would like to use a Raspberry Pi4 to control a syringe pump [(see datasheet here and in particular the quick start manual on page1)][1] The connector cables I used are RJ11 from the Pump to RS232 (...
Marco Bobinger's user avatar
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1 answer
1k views

How to clear UART RX error for pico (RP2040)?

While working with a RPi Pico UART RX routine in C using pico-sdk, I have realized that uart_get_hw(uart0)->rsr; reports an error - that is, it has a value different from 0 (in my case 13, which is ...
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