9 votes
Accepted

Thought I found serial port - broke embedded device instead! Help?

Frying your board: Just touching one single pin of a chip, or connecting it to ground over a reasonably high-resistance voltmeter, will generally not fry a board. However, there are ways to fry a ...
Guntram Blohm's user avatar
8 votes

Thought I found serial port - broke embedded device instead! Help?

I had to add just a few things to have a clear mind (although the other answer is really good and got my up-vote already). Single pin touching with a probe can blow up your HW. And I do not mean the ...
Spektre's user avatar
  • 1,384
8 votes
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I really struggled to figure it out, now can anyone help me reverse engineer this checksum?

The key is getting getting a megaton of samples, so that the analysis has something to feed on. It really helps if you can stick the samples in a database table or dictionary that can be queried ...
DarthGizka's user avatar
  • 2,010
5 votes
Accepted

Hex timestamp decode

import sys import os if(len(sys.argv) != 2): sys.exit("usage %s 0xdead" % os.path.basename(sys.argv[0])) if((sys.argv[1].startswith("0x")!=True) or (len(sys.argv[1])!=6 )): sys.exit("0x ...
blabb's user avatar
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4 votes
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Need help with a USB gaming mouse

my understanding of USB is very low at best (even if I do develop some simple USB devices for a living) so read this with major prejudice... Your driver class and configuration must match the USB (...
Spektre's user avatar
  • 1,384
4 votes

Router's serial port only outputs garbage

If this is data, then there should be a common clock, with the raising/falling edge signals all on individual ticks of that clock. I scaled the bottom half of your scope output by 500% horizontally, ...
Guntram Blohm's user avatar
4 votes
Accepted

Reverse engineering serial communication CRC algorithm

This question seems simpler than you might expect. Since as OP noted, the code is irrelevant to validation mechanism used in the discussed system, I shall ignore it. It is indeed irrelevant as will ...
NirIzr's user avatar
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4 votes

Reverse engineering the IBM BSC (Bisync) protocol

If you have known data and a known CRC, and an unknown value (like the initial CRC value or the final XOR value), you can always loop through all possible values and find those that give you the ...
Malvineous's user avatar
4 votes
Accepted

Reverse engineering the IBM BSC (Bisync) protocol

SOLUTION I got help from a guy named Peter. He gave me a piece of test code in C. The CRC algorithm looked pretty similar to the ones I already tried. But what was important was that he pointed out ...
Mattis Lind's user avatar
3 votes

Reverse engineering USB peripheral driver

Well, your question is a bit broad as it stands, but let's take it one by one. Typically (but not always) drivers for printers these days are user mode drivers (UMDF), which means you're looking for a ...
3 votes

Why can't I decode this UART signal?

Answering my own question: just figured out that the board that the CP2102 decoder was mounted on had a LED wired to the RXD line. It happens that this board was poorly designed, and this LED was set ...
Bernardo Donadio's user avatar
3 votes

Router's serial port only outputs garbage

Your signal is very degraded: your rise and fall times are too slow relative to the bit rate. If the signal really looks as your scope plot shows, and this is not just a measurement issue, then it's ...
marcan's user avatar
  • 131
3 votes

Decoding proprietary 485 comms

I would hardly call this an answer, but I can't comment yet.. You need additional data. Have you tried opening the outdoor unit and examining the board that you're communicating with? you might find ...
Eli K's user avatar
  • 151
3 votes
Accepted

2byte checksum for serial traffic

It is a CRC-A checksum. 16bits. Preface: From my research this is the crc for that standard. Its calculated from start of packet up to checksum https://crccalc.com Put 8209 and check the result: ...
Thomas's user avatar
  • 178
2 votes

Anti-theft system rs485 keypad

It is quite possible the master device requires keypad to answer within a specific time window. Adding a man-in-the-middle violates these conditions. To analyze data direction, you can try connecting ...
Vladislav Ivanov's user avatar
2 votes

Sniffing serial Bluetooth traffic on Android

According to this StackOverflow answer, Android has a setting in Developer Options from 4.4 onwards. You first need to enable Developer Settings (if you have not done so already), then enable “Enable ...
user149408's user avatar
2 votes

UE Megaboom serial protocol

If the device doesn’t respond to unsolicited traffic, it probably needs some specific commands to return results. You could try bruteforcing it by sending random data but it’s a chancy business. A ...
Igor Skochinsky's user avatar
  • 36.5k
2 votes
Accepted

Decipher variable length serial protocol

I understand your Arduino serves as a relay in the middle between the controller and the LCD. What you could do (not extremely exciting, but you did not mention whether you made similar experiments ...
josh's user avatar
  • 1,964
2 votes

Finding JTAG/UART Connections

In the second picture on the bottom there is an nonpupulated connector, whose pins are labeled RX and TX. Thats at least one of maybe more uart interfaces. You should additionaly check the traces on ...
user5626466's user avatar
2 votes

Decoding proprietary 485 comms

I managed to decode the protocol on XYE connection. My findings are here https://codeberg.org/xye/xye The XYE connection is the bus between a central controller and the indoor units. The bus from the ...
xye's user avatar
  • 21
2 votes

Reverse engineering checksum from RS-485 device

The protocol spec clearly does not apply to your device, so don't bother trying to use its checksum calculation. However it may be similar enough to provide some clues to the actual protocol. The ...
Bruce Abbott's user avatar
2 votes

Identifying a toner chip and its communication protocol to re-program it

If you have a Brother printer you can use these instructions I found on Amazon on how to reset your cartridge chip, it worked for me. "I was able to reset my toner cartridges for this model by using ...
Tim Do Brava's user avatar
2 votes

Help decoding this UART serial signal

Every UART packets contains a start bit what is always 0 and 1 or 2 stop bit(s) what is/are always 1. If you check the middle of your trace there are single 1 bits with some spaces between them. Every ...
0x6261627564's user avatar
2 votes
Accepted

Reverse engineering 12-byte serial packets from doorbell

Based on how you have laid it out, you look to have it mostly mapped out correctly, The preamble (control device wake up) would be a general broadcast message to all units on the data bus, (The pull ...
Reroute's user avatar
  • 136
2 votes

Wrong keyboard strokes sent to serial in putty

You have probably tried already but other baud rates? 9600, 1200, 2400, 57600 Seems like 8,N,1 is common? 8 DATA, No parity, and 1 STOP bit Maybe helpful? https://stackoverflow.com/questions/...
Liam Mitchell's user avatar
2 votes

Reverse UART communication protocol

From my question: It seems to work :) Is the message length more or less ;) See procedure bellow Still wondering if it's a "common/standard protocol"? Procedure I have removed the module ...
KumZ's user avatar
  • 141
2 votes
Accepted

determine proprietary 16-bit floating-point format

Maybe it is the temperature in Kelvin: 311 - 80/2 = 217K = -2.15°C Or the offset is different than 80/2. A 16-bit floating-poitn format, especially a different one from IEEE-754 is highly unlikely. ...
ProjectPhysX's user avatar
2 votes

Reverse Engineer 16 Bit error checking byte calculation

So, after reviewing This following Stack Overflow Question I opened up an excel and made some tests and effectively Sum of all bytes is the calculation Hex ff 00 00 04 00 00 00 00 00 13 00 ...
Pau Coma Ramirez's user avatar
1 vote

How to identify SWD (Serial Wire Debug) pinout?

Not aware of any similar software tools for SWD, but: If you can see or infer the chip part number, look at the data sheet. Look for test points (or connectors) that may be used in factory ...
esrever's user avatar
  • 55
1 vote

Reverse engineering USB peripheral driver

Answers to this question deal with generic reversing of USB devices, but if you want to start from the driver files, find the printer in Device Manager, go to properties, then Driver tab-Driver ...
Igor Skochinsky's user avatar
  • 36.5k

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