Questions tagged [uart]

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

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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 ...
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-1 votes
1 answer
30 views

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 ...
0 votes
1 answer
40 views

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 ...
1 vote
2 answers
69 views

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 ...
1 vote
0 answers
44 views

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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3 votes
4 answers
76 views

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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0 votes
0 answers
266 views

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 ...
0 votes
1 answer
27 views

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&...
2 votes
1 answer
83 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 ...
0 votes
0 answers
37 views

How to connect UART and TPM in Raspberry pi 4

I want to connect Infineon 9670 tpm 2.0 with raspberry pi 4b. TPM takes GPIO pin 1 to 26 and UART needs pin 8 and 10. So basically I cannot connect both simultaneously. (which is the requirement in my ...
1 vote
0 answers
89 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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0 votes
1 answer
199 views

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 ...
0 votes
2 answers
144 views

(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 ...
1 vote
1 answer
44 views

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 ...
0 votes
0 answers
31 views

Raspberry pi 4, data received from UART different from USB serial

I'm new to Raspberry pi. I writing a program that send/receive data from serial. Everything works fine with the USB to RS232 cable, but now I'm testing with the UART pins to RS232, and the data sent/...
0 votes
0 answers
154 views

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)....
0 votes
0 answers
202 views

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 (...
0 votes
1 answer
369 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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-1 votes
1 answer
135 views

Rx, Tx/UART not being detected by Pi? What is wrong?

I'm working on Serial communication between the Raspberry Pi and the Arduino, with the Raspberry Pi serving as master. I connected, using a logic level shifter, Arduino's Rx (Software Serial was used ...
  • 89
0 votes
0 answers
30 views

Enable shell interface on USB but not UART

I have a headless setup running on a CM3+ board. The custom interface PCB I'm using breaks out UART0 on pins 51 and 53, and USB on pins 165, 167 etc. The USB port usually has a WiFi antenna plugged ...
-1 votes
1 answer
102 views

Turn LED off and on using I2C, SPI or UART GPIO Pin

I have project requiring several simple LEDs and buttons, MORE that the number of ‘simple’ GPIO pins. Can I turn the LED TOTALLY OFF and on using a IC2, SPI, or UART pin? Can those pins be programed ...
0 votes
0 answers
71 views

Indecipherable Characters with UART on Pi 2

I am attempting to use the UART pins on the Raspberry Pi 2 to interface with the console port on a Cisco Access Point. I've stripped an old RJ45 cable to connect the right TX, RX and GND pins from the ...
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0 votes
0 answers
39 views

Conflict between UART and cv2 Video Capture

I am attempting to communicate with an Arduino through UART using an Raspberry Pi 4 Model B. The Python script is grabbing frames from a Raspberry Pi Camera Module v2, pre-processes them and checks if ...
0 votes
0 answers
235 views

Raspberry pi and nextion touch screen communication using python

I have tested several python codes to set up the communication between raspberry pi and nextion touch screen (I used TTL serial GPIO 14 and 15). Unfortunately, the communication is not stable, the ...
0 votes
0 answers
14 views

Update scripts on OS via USART interface and uC

I have connected CM 4 (IO Board) with STM32F103 via USART interface. My goal is to find correct way to update pythons scripts, system settings etc on my RPI OS without direct connection with board, ...
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0 votes
1 answer
172 views

Missing dtbo overlays in Yocto build for Compute Module 4, what do I need to get them added?

So I have a problem that I have half solved and was hoping someone would know how to solve the rest. So yesterday I encounted a problem that I asked and partially solved at the link below. CM4 Uart 0 ...
0 votes
0 answers
49 views

Can't modify UART 5 baudrate

I'm trying to communicate a NUCLEO-F746ZG with a RPi-CM4 thru the UART5. I need, at least, a baudrate >= 4000000. Using the stty -F /dev/ttyAMA2 4000000 I get the "unable to perform all ...
-2 votes
1 answer
274 views

UART make sure to prevent data loss; choppy binary transmission [closed]

If I use UART to send sensor data from a Pi Pico to another computer (received via /dev/tinyUSB0), does the "default protocol" have any sort of error correction? I guess I don't need to ...
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0 votes
2 answers
752 views

Possible to send data from a Pi Pico via USB while running CircuitPython?

I have a question on the interaction between Pi Pico, CircuitPython, and USB. I need a way to send a data stream from the Pico to another computer where it will be received on a USB port (it's the ...
  • 482
0 votes
1 answer
71 views

How to connect Sim800c development board to raspberry pi 3

i bought this development board Professional Small Size SIM800C GSM GPRS Module Quad-band Development Board Module Suitable for Raspberry Pi (blue & silver) https://www.amazon.it/dp/B07NVZ59JS/ref=...
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0 votes
1 answer
209 views

ch341-uart converter randomly disconnects from Raspberry

I'm facing problem, with ch341 uart chip. ch341 works normally at startup for about 120seconds. After that it disconnects. I'm attaching dmesg bellow. What it could be a problem? Tried with different ...
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0 votes
0 answers
151 views

Connecting the pi to a pixhawk flight controller

I am building a drone using a Pixhawk 2.4.8 flight controller. I want to add a pi with a picam to my build. I have followed this manual for connecting the pi to the controller. Therefore I have made a ...
  • 101
0 votes
1 answer
149 views

How can I "test data" coming in to a Pi from an UART device connected via TTL-to-USB

I've got a Waveshare PN532 RFID reader/writer. I want to use it with a Pi 4B, but since it is already using a HAT with no free GPIO, I want to use it in UART mode, but not connecting to the GPIO pins ...
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1 vote
1 answer
2k views

How many (usable) serial ports does Pi Zero 2 W have?

The Raspberry Pi 1, 2, 3 and Pi Zero / Zero W all have two UARTs (PL011 + mini UART). The Raspberry Pi 4 and 400 have six UARTs (5 x PL011 + mini UART). This is from the official documentation. I have ...
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3 votes
2 answers
812 views

Does a UART connection require shared ground?

I'm a novice with electronics but not Linux. This situation has had me scratching my head for two nights. I connected a Pi Pico to a Raspberry Pi 4 via UART, and managed to receive messages sent from ...
0 votes
1 answer
149 views

Connecting Fingerprint Scanner without USB converter

I'm trying to connect a fingerprint scanner without using a USB converter. I have it connected to pins 8 and 10 (GPIO14 and 15). I was following a tutorial but it required me to use the command ls /...
-1 votes
1 answer
130 views

GPS Daemon not working on RPi, but works on my Arch PC

I followed this Adafruit Tutorial; trying to make GPS Daemon work on RPi4- on Raspberry OS minimal. Here is my situation: I can see NMEA data is coming thru minicom -b 9600 -D /dev/ttyUSB0. There is ...
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0 votes
0 answers
272 views

Enabling uart0 (ttyAMA0) and uart1 (ttyS0) on CM3 with Ubuntu 20.04

I am trying to enable the onboard uarts with a CM3 running Ubuntu 20.04 Server. I had no problem changing /boot/config.txt on an older raspian image, but on this one it doesn't work. I would like ...
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1 vote
3 answers
145 views

UART data collection and logging taking too much time

So, I am sending data to RP1 B+ model through UART from a microcontroller. I am using minicom to collect data and log it in a .txt file. I am sending around ~800 kB of data and using a baud rate of 1....
0 votes
0 answers
113 views

Serial communication over uart - Android raspberry pi 4

Is there a library/source code available for serial communication over uart for the raspberry pi 4 running Android?
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0 votes
2 answers
152 views

Debugging potentially broken uart pins

I have recently been working on a bare metal project on a raspberry pi. I have been using a uart to usb cable to for logging, which has been able to send messages to my computer. Recently however, it ...
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-1 votes
1 answer
75 views

UART Rx TX pins not reading sensor output RPI3

This is my first pi project so I'm a bit new at this. I'm 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/...
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0 votes
0 answers
162 views

C# .NET Core application cannot open serial port

I'm running a .NET Core application on Raspberry Pi OS (32-bit Debian). pi@raspberrypi:~ $ cat /etc/os-release PRETTY_NAME="Raspbian GNU/Linux 10 (buster)" NAME="Raspbian GNU/Linux&...
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1 vote
2 answers
2k views

How to enable the second serial port on a pi4

I am trying to use the second serial port. In /boot/config.txt I have put at the end : # swap UARTs dtoverlay=pi3-miniuart-bt dtoverlay=uart2 enable_uart=1 I have checked and re-checked the pin ...
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1 vote
1 answer
1k views

UART communication Raspberry Pi Pico to Raspberry Pi

*Update, new main.py for pico and read_serial for RPI 4. *I am having the same problem with uart.write(), see below. I am trying to communicate with a raspberry pi pico with my raspberry pi 4 over ...
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1 vote
1 answer
175 views

How can I make gpsd restrict to a certain serial port?

After reinstalling Raspbian Buster I'm always running into an issue with my gpsd 3.17: Despite the fact that I start it with the corresponding device file /dev/ttyS0 as a parameter (because the GPS ...
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1 vote
1 answer
239 views

unable to gps data serially in raspi 4

I am trying to get ublox zed f9p module work with raspi 4. I am using this module I am running on ubuntu 20.04 desktop version on raspi 4 and i have connected the module serially(/dev/ttyS0) to my ...
2 votes
2 answers
55 views

How can I prevent Raspbian from resetting user privileges on /dev/tttyS0?

I've got a GPS module hanging on the TTL UART wires of my Pi 3B. I don't access the module directly, but via gpsd. Now I've got the following issue: At every reboot, Raspbian (Buster) seems to reset ...
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-2 votes
1 answer
459 views

Raspberry Pi Zero w two UARTs

I use on my RPi Zero UART ports on GPIO 14&15 on device /dev/ttyS0, and that is ok. But I need another UART port, can I connect to micro USB port on board USB-UART converter CP2102 to get the ...
-1 votes
2 answers
466 views

RPI0 W unable to read UART data

I have enabled uart serial port /dev/ttyAMA0 on my raspberry pi zero W. I was able to successfully connect the rpi uart rx and tx pins and check if i'm able send and receive data between these rpi ...

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