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Questions tagged [uart]

49 questions
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Retrieve file over serial without kermit and lrzsz

I have an embedded Linux on a custom board and I would like to send and receive file over its serial port. The only way to communicate with this device is over serial and the device offers a console on this serial port. This board doesn't have…
Arkaik
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RaspberryPi serial port

I have a Display that I want to write to. This is possible over the serial port. When I use a USB to RS-232 Converter, that thing works like a charm. I even tried using only the RX, TX and GND wires of the serial converter, and it still works. Now I…
jukisu
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How to active the second console to a FreeBSD guest running in bhyve?

Background I'm running FreeBSD 12.1-RELEASE as a host for bhyve virtual machines. I have a FreeBSD 12.1-RELEASE guest running inside a VM. I would like to have two TTY-class devices configured for it. According to the manual page, in order to start…
Mateusz Piotrowski
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socat - UART logging and redirecting

I am currently trying to log all communication from and to /dev/ttyUSB0 and simultaneously be able to connect minicom/screen to the same device for interaction. I tried a couple of tools and tutorials but they all seem to occupy the device, so I…
Chris
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How to use UART pins on Orange Pi zero?

I want to use UART1 or 2 (see picture) on the Orange Pi zero. But when I try to open the port with screen /dev/ttyS1 Screen terminates. I found here that I needed to add "overlays=sun8i-h3-uart1" in /boot/armbianEnv.txt but someone on that forum…
MatMis
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Kernel parameters "console" and "earlycon" refer to old hardware?

I first found this by investigating parameters for earlycon but found that the options for console look almost identical. Both are present below and were taken from this source: From documentation for console we have: console= [KNL] Output…
sherrellbc
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How to configure embedded kernel to use serial line for PPP instead of TTY

I am about to start working on an embedded system which runs kernel v2.6.x. It is configured to use its serial line as a TTY (accessible via e.g. minicom, stty), but I want to run IP over the serial line so that I can run multiple multiplexed…
Mark K Cowan
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Bash script - Watch serial-port for specific string, then send back commands

I try to use a bash script to watch the serial-port for a specific string. If this string is shown, some commands should be send back to the connected device. It´s a router I am connected to. It is a router I am connected to and I want to send the…
some1
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Is there a limit to the number of FTDI connections on Debian 9?

I have a Debian 9 box, and if I plug in 1 of my devices, its UART shows up in both lsusb and in the output of ls /sys/bus/usb-serial/devices/. When I attach 2, the 2nd one always shows up. But for some number greater than 2, no new entries appear in…
Alex Shroyer
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Failing to Enable UARTs on Beaglebone Black

Short and General Question I'm running Debian 9 (Stretch) on a Beaglebone Black with kernel 4.9. I have tried following the instructions that I've found online, but have thus far been seemingly unable to configure its UART devices. How do I…
igal
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How can I determine if a latency is due to a driver or the scheduler?

Using an oscilloscope and toggling some pins I sometimes see latencies of 1-2 seconds from when an 8-byte UART packet is transmitted to when a blocking read returns. The packets are 1 second part with a few milliseconds of jitter. I also measured…
Kenny
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What are the implications of setting the baud rate of a terminal from userspace?

Sometimes I just need to read from a serial device, so I skip the complexities of minicom or screen and just cat. However, this only works if I first set the baud rate of the terminal using stty before attempting to open the file. This data…
sherrellbc
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Wireshark: Remote capture over UART

TL;DR: How to pipe properly over UART the output of a remote tcpdump to a local wireshark ? I try to capture packets that flow through an embedded device to which I don't have the ability to install anything. Fortunately, there is a getty opened on…
Cilyan
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Detect what driver is loaded for a UART connected chip?

I'm trying to detect what driver is responsible for providing the HCI interface for the Raspberry Pi 3 Bluetooth module. Here is an equivalent of what I'd like to achieve but for a USB dongle. user@lime:~$ hciconfig hci0: Type: BR/EDR Bus: USB …
TheMeaningfulEngineer
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How to redirect GRUB2 output to a MMIO serial UART?

Is it possible to redirect GRUB2 output to a MMIO serial UART? For example I have a UART that is displayed in a Linux boot log as: AMDI0020:01: ttyS5 at MMIO 0xfedca000 (irq = 4, base_baud = 3000000) is a 16550A To get kernel boot log, I just add…
kostr22
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