Questions tagged [uart]

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

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573 views

Bare Metal RPI 3B UART not working

I have referred many tutorials to get UART working in bare metal environment on RPI 3. https://github.com/dwelch67/raspberrypi/tree/master/uart05 https://github.com/mrvn/RaspberryPi-baremetal/tree/...
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4k views

Raspberry Pi and LIN Bus

I want to implement a LIN Bus using a Raspberry Pi 3. The RPi will be the master controlling slaves on the LIN Bus. My idea is to use the Raspberry Pi UART, but I am not sure to what extent this ...
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660 views

Disable onboard Bluetooth device and remap UART0 on Windows 10 IoT Core

We would like to use Gertbot card on Raspberry Pi 3 to control motors and to read distance sensors. For that, serial communication using UART0 on GPIO pins 8 and 10 is required. Observing Raspi serial ...
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2k views

Raspberry Pi 3 Bluetooth Baud rate

How do I increase the available baud rate of the bluetooth module for the Raspberry P1 3 model B? I have tried editing the /boot/config.txt file with: init_uart_baud=1000000 init_uart_clock=16000000 ...
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91 views

pySerial - UART - Determining when a message has actually been sent (callbacks?) (RTS/CTS hacking?)

For reasons (explained at the end of the post) I need to have a pin change state immediately as the UART finishes outputting a set of bytes. I'm using pyserial & pigpiod on a RPi3B+ and bluetooth ...
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601 views

Pi CM4 - Additional UART enabling does not work

I have a Compute Module 4 here, and i want to enable more UART ports The Datasheet, Page8 specifies that uart 2-5 can be enabled since their ports are not used by anything else I've run raspi-gpio get ...
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74 views

Mini-UART on RPi 3 and earlier loses synchronization if parity bit used

I have a sensor which every 1 second spits out a 32-character serial stream at 9600 baud. I hooked it up to the mini-UART pins on the GPIO connector. What I saw was bad data. After staring at the ...
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105 views

How can I reconfigure the UART on the fly?

I have a Pi Zero with Raspbian which I'd like to use as a logger device with WiFi (it's not a W, I'm using an external WiFi stick). I need the UART to communicate with a microcontroller but sometimes ...
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1answer
2k views

SIM800 GSM Module To Raspberry Pi UART Serial Communication Problem

I am new to Raspberry Pi Zero and I want to connect it with a GSM module for GPRS connectivity. I bought the SIM800A GSM module but its LED is not even blinking one single time. I am able to turn on ...
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258 views

SPI0 and UART0 interference caused by SPI interrupt

I have a raspberry CM3 running a custom Linux version created by buildroot (kernel: 4.19.44-v7). The CM3 is configured to be part of a measurement system that is used on a quad-bike (so a lot of ...
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1answer
1k views

RPi Zero: Two UART devices at the same time

I need to read UART data from one device, and send different data to the other device, all via raspberry pi zero. It has only one UART TX and one UART RX on GPIO pins, but I heard that it is possible ...
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4k views

How do I test if my UART port is working? Simple example... loopback-test

I am working on a NMEA(GPS)-datalogger for a drone. I followed the tutorial from fishandwhistle and createt this script: #!/usr/bin/python3 import os, time, sys, glob, datetime, syslog, pynmea2, ...
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Raspberry pi 3 uart not working

I've done almost any tutorail I found in the internet, but I cant get successful communication with uart in RPI3 Ubuntu Mate. I've added enable_uart=1 and dtoverlay=pi3-disable-bt and core_freq=250 ...
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1answer
1k views

UART pins not reading sensor output RPI3

This is my first pi project so im a bit new at this. Im trying to connect a senseair K-30 CO2 sensor to the pi via the UART gpio pins. This is the sensor I am using: https://www.co2meter.com/products/...
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415 views

Lost Serial on Pi3 running Pixel

I have just upgraded to the latest OS Raspbian Pixel and my serial connection has stopped working. I know that the hardware is configured correctly as it worked pre-update. I have updated to the ...
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970 views

u-Blox SARA and ModemManager

I have a u-Blox SARA-U270 device connected to a Raspberry Pi 3 via UART GPIO pins, that I am trying to use for a 3G connection as a backup. I would like to manage this via NetworkManager/ModemManager ...
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846 views

How can I make the ITEAD PN532 work on the R-Pi via UART?

I have used the Adafruit PN532 before on the R-Pi (A and B+) via UART and it works just fine but I haven’t been able to make it work for the ITEAD. The ITEAD supports I2C, SPI and UART. On this link, ...
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2k views

Using Raspberry Pi with Arduino GSM/GPRS Shield

Raspberry Pi Model B GEEETECH Arduino GPRS Shield V1.0 (bought from: bit.ly/1G0KYR7) ^ Similar somewhat to: Seeed's GPRS Shield V1.0 | Link: seeedstudio.com/wiki/GPRS_Shield_V1.0 (has more ...
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4k views

Receive data from uart with Raspberry Pi mono c#

From today, after updating libraries Mono C# on my Raspberry Pi Rev 2 Type B (wheezy), the communication via serial no longer works, it seems to me very strange, because yesterday with the same ...
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My DT overlay doesn't work

I'm trying to activate the miniUART with RTS and CTS signals (on an RPi Compute Module). For this purpose I've created an overlay: /dts-v1/; /plugin/; /* Enable /dev/ttyS0 with RTS and CTS signals ...
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RX pin of ttyS0 is always high

I am trying to configure a Pi 4 and eventually a CM3 for modbus communication. so far I have been able to see the TX send from the D+ and D- of the max485cpa+ but I have been unable to receive data ...
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2answers
183 views

How to enable both UART (ttyS0 and ttyAMA0) on Raspberry Pi 3b?

I've already read dozens of manuals and stack topics, but I do not figure out if it even possible run both UARTs on RPi 3B. Some tutorials advice to map uart to other pins in /boot/config.txt I tried ...
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57 views

redirect U-Boot Console to UART4 in rpi cm4 board

I am using Raspberry pi CM4 for my project. The Hardware is designed in such a way that i need to redirect all the debug messages coming through serial UART0 to UART4. I Use U-Boot as a boot loader ...
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1answer
84 views

Slow UART communication between Raspberry Pi Zero and 4B using pyserial

I'm testing serial communication between two Pi's (Zero -> Pi 4) with Python pyserial library. I am using Zero as camera with preprocessing and sending preprocessed data to Pi 4 via UART (/dev/...
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42 views

Can four UARTs plus either an SPI or i2c connection be used at the same time on a Pi 4?

Since using 5 UARTs at the same time on a Pi 4 is apparently not possible, is there any reason why 4 UARTs plus either an i2c or SPI connection at the same time (one or the other) would not work?
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415 views

How can Rpi4B use multiple on board and USB based UART / serial ports?

there. I am trying to use rpi 4 to access my own device through UART. However, the number of UART port isn't enough for me since I'm trying to access more device in same time. Thus, I want to know if ...
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68 views

reading from 2 UART at the same time

I am reading values from 2 UARTs. i want to read at the same time (without time shift between the 2 UART) the values they send in order to add them. How do I achieve that? I am searching on google, I ...
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418 views

Raspberry pi 4 model b uart is unable to write

I got some questions about uart in raspberry pi 4 model b. I used to run my program in rpi 3 model b+, but everything went wrong when I tried to do the same thing on pi 4. First of all, each time I ...
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325 views

RPI Serial Communication through USB

I am trying to set up serial communication between my Raspberry Pi Zero W and my PSoC. I want to do this through a normal microUSB to USB 2.0 converter cable, which looks somewhat like this picture: ...
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88 views

RPI3b+: UART serial communication problem

I have my RPI setup to communicate serially with another board. Currently, I have a usb to serial converter which is plugged into one of the RPI ports. This works well but, I want to take that out and ...
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82 views

Uart Communication pi to pi

I first connected two raspberry pi, one is Model 4B(transmitter) and another Model 3 B+(receiver) via Uart. Done all uart enable steps (sudo raspi-config>Interfacing Options>Serial>Serial Interface is ...
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63 views

USB ports for 4G modules disappears after resetting the 4G module

I am using the EC25 quectel LTE module with Raspberry Pi 3 Model B. I can access the internet using serial pins of raspberry pi i.e. UART Tx and Rx. I can find ttyUSB[0-5] in ls \dev. I am sending AT ...
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161 views

Getting garbage characters on RPi3 UART console, logs on HDMI are perfect

I have searched a lot on internet and tried all suggested solutions like criss-cross connection, checking loose connections, changing baud_rates and using GND connection for UART, but nothing seems to ...
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50 views

Could not read all bytes from /dev/ttyS0

I try to send some data to a module which connected via UART /dev/ttyS0, I send a standard command to module and module send me back a 13 bytes acknowledgment, but the first 5 bytes of ack not ...
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712 views

Interfacing SIM800L with PPP [LCP Terminated by Peer]

I am using SIM800L, and managed to interface it with RPi3. After successful configuration on /etc/ppp/peers/rnet, my file looks like this connect "/usr/sbin/chat -v -f /etc/chatscripts/gprs -T ...
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1answer
879 views

use GPIO and/or UART to slow initiate K-line (ISO9141-2) communication with Audi ECU

Related to this question I'm learning to use the Pi GPIO and Python serial to communicate through an IC (L9637D) to interrogate PIDs for alarms etc. I can't get past the slow initiation sequence! ...
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1answer
153 views

PIGPIO bit banging UART - SLR to plaintext

I've managed to read UART input by SLRO and SLR commands from pgpiod, however, SLR returns UART bit-banged data in the following format: [number of read bytes] [bytes] http://abyz.me.uk/rpi/pigpio/...
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Do Rpi3 UART devices inherit their device ID from the on-board UART0 controller (GPIO pins 8 & 10)?

I am working on a device prototype which reads load cell data to an Arduino which sends the load cell data via (hardware, not USB) Serial to the Rpi3 running Win10 IoT. The communication link ...
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49 views

UART 0 PCLK not registered (pi 3)

I'm using a rpi 3 and so to use the UART 0 I had to disconnect the bluetooth from it: enable_uart=1 dtoverlay=pi3-miniuart-bt dtoverlay=midi-uart0 in /boot/config.txt It works great but now at ...
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304 views

Toggle UART (enable_uart=1) without rebooting

Which pins can can I manually toggle to enable or disable UART on a Raspberry Pi Zero or 3B+ without rebooting? As I understand, /boot/config.txt is parsed before Linux is started, but I don't mind ...
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94 views

Adafruit Ultimate GPS with Rpi 3 "Permission Denied"

I am trying to connect an Adafruit Ultimate GPS to my Raspberry Pi 3 and read data from it using the WiringPi Serial library. I have set the serial connection up and removed the serial console through ...
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117 views

What is (typically) GPIO's UART RXD input impedance in a RPi 3 Model B?

I'm sorry if this is a trivial (or already answered) question, but I really couldn't find an answer on the web. I'm trying to connect an AVR board, which operates at 5V, to a Raspberry Pi 3 Model B's ...
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USB Dongle not working if it's connected by default to my Raspberry Pi

I have a USB Dongle That I communicate with it using UART commands. So if I connect my dongle after starting the system I can send commands and I'm able to receive info, But if I leave the dongle ...
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2answers
2k views

Raspberry pi 3 reading serial port

I have a python code that reads the serial port of the raspberry pi 3to obtain GPS positions from a fona808. The code works for some time and then throws this error. Traceback (most recent call last):...
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2k views

Can't Login to Pi0 console from Pi3 B+ via UART Serial USB-TTY Adapter

I am new to RPi's so bear with me please: I am trying to log in to the Pi0 console via sudo screen /dev/ttyUSB0 115200 but I just get a blank screen. Ouput of dmesg | grep tty: [ 0.000000] ...
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0answers
3k views

Very slow serial port reading

I have the following code, used on an RPi2: import serial import time # Set up serial port ser = serial.Serial( port='/dev/ttyAMA0', baudrate=921600, parity=serial.PARITY_NONE, ...
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0answers
161 views

PI3 Ubuntu Server 16.04.03 - UART issue

I'm trying to setup UART, for a final year project at university, on the PI3, I need to switch ttyAMA0 to the GPIO pins in place of ttyS0. I have tried adding the device tree overlays 'pi3-disable-bt' ...
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71 views

Struggle to read data with serial port of Rasp3

Sorry if I am asking something very basic, did not find any good post on how to handle this.. I am following a tutorial on how to communicate with my PI 3 using UART. I followed theses steps: Delete "...
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187 views

Flashing Arduino sketches from RPi using UART interface

I am communicating with two Arduino Unos, using my Raspberry Pi 3 via the UART interface. I have established serial communication between them. But I was wondering if there was a way to use this to ...
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0answers
2k views

How do you get an RFID reader to work with Raspberry Pi 3 and UWP?

everyone! This question is in relation to my Raspberry Pi 3 and Windows 10 IoT Core project. I intend to use an RFID Reader (short range only), along with an universal windows application, plugged to ...