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Questions tagged [xmodem]

XMODEM is a simple file transfer protocol developed by Ward Christensen.

38 questions
5
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4 answers

How to read negative byte values in Java less than -128

I'm reading data from another system using the serial port. I'm reading packets of 133 bytes. The second byte is the packet number and the third byte is the negative value of the packet number. The problem is that the type byte has a range of -128…
rohini
4
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0 answers

Android Xmodem file transfer over Bluetooth

Im building an android app to send files to my device over bluetooth. This sounds simple enough, however the device can only receive data with the XMODEM file transfer protocol. After extensive searching, I have not found any useful resources or…
jstm
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2 answers

CRC-CCITT (XModem) implementation in javascript

i'm trying to implement a CRC-CCITT (XModem) check in javascript without success. I need it in order to send socket string into a controller via RS232. does anyone know how to do it? or perhaps is there a sample code somewhere?? I would appreciate…
Salmonela
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1 answer

XModem file upload example in C?

Does someone have a code example in C for the receiving end of a file upload from hyperterminal using XModem? For Linux or other? Thank you and best regards, Bert
quadmore
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3
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1 answer

Automate xmodem file upload

I have a device where a software update is done by uploading a file through xmodem. I was able to do this in two ways using the lrzsz (http://ohse.de/uwe/software/lrzsz.html) package. 1) Using screen screen /dev/tty.myserialdevice 115200 and…
benjay
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2
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3 answers

CRC calculation in Java

I'm reading a file from serialport using x-modem protocol and 133 bytes packet. I'm reading in that 1 byte is SOH 2 byte packet number 3 byte nagative of packet number next 128 bytes data 2 bytes CRC sent from other…
rupeshkumar
2
votes
1 answer

ModuleNotFoundError: No module named 'xmodem' on raspberry pi

Really new to programming in Python and I am trying to build a flask web app for a raspberry pi that would DNC g-code from a text file over the serial port to an older HASS cnc mill. The mill uses the XMODEM protocol. I have been following the…
drescheg
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2 answers

Xmodem-CRC protocol in c# problem

I'm porting a C++ xmodem protocol to C# and I'm having an issue with the CRC check. The application uploads files through a modem using the xmodem 128 byte protocol with CRC. I test it using Hyperterminal. I can upload small files fine, but when I…
Dan H
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6 answers

XMODEM for python

I am writing a program that requires the use of XMODEM to transfer data from a sensor device. I'd like to avoid having to write my own XMODEM code, so I was wondering if anyone knew if there was a python XMODEM module available anywhere?
alvaro
2
votes
1 answer

Ensuring XMODEM Transfers a File Faithfully

I'm using XMODEM to transfer a binary file from an Ubuntu VM to an embedded Linux target, like so: $ sudo screen /dev/ttyUSB0 115200 $ rx test CTRL-A: $ exec !! sx -b test Now, "test" transfers successfully, but when I inspect it on both the VM…
Ed King
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1 answer

Using Pyserial to send a file?

I have a Raspberry Pi connected to my Macbook Pro by two radio modules. I have been successful so far in sending strings and commands from one device to the other using pyserial, however, I cannot find a way to send a text file. Like on…
user3117351
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3 answers

Can I use the xmodem protocol with PySerial?

I have a working connection with my serial device via PySerial, but I also want to transfer files via the xmodem protocol as part of my program. Which would be the most platform-neutral way to do this? Worst case, I could close() my serial.Serial…
lfaraone
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1 answer

What is the value of size to be provided for the getc method in xmodem protocol?

I'm trying to transfer a file using the XMODEM protocol. I saw and did not understand the solution provided in: Can I use the xmodem protocol with PySerial? I saw xmodem package link. What is the value of size to be provided for the getc method? It…
manz
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1 answer

Implementation of Xmodem protocol in Java

How would I receive a file over a serial port in Java using the XMODEM protocol?
sumesh
1
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2 answers

How to apply xmodem CRC on generating and checking

I've iterated of lots of articles - for some reason I couldn't find any which describes what must be a simple procedure: How to combine a calculated CRC with the original message, so that calculating CRC again results in 0 (=checks out as correct)?…
jcoppens
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