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Questions tagged [logic-analyzer]

A logic analyzer is an electronic instrument which visualizes a set of digital signal across time. It can only display logic levels and their transitions, not analog levels.

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What effect does a logic analyzer probe have on a circuit?

I have an MCU controlling a LED sign. This sign speaks the HUB75 protocol, which is essentially a large shift register. Being a shift register, this requires a clock signal to be generated, which the ...
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32 views

stm32 uart issue serial monitor vs logic analyzer

I am writing data serial monitor via hal_uart_transmit and it works fine, but when I monitor same serial bit pattern in logic analyzer I see extra two bits have the logic high state, why is that? for ...
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32 views

Reading SPI transmission in logic analyser

I'm trying to use an Analog Discovery 2 to read SPI transmissions from my mbed. Code: ...
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53 views

How to know voltage used on a data bus?

How do you find out what voltage is being used on a data bus for the high signal? On a small electronics I guess you can assume it will be 3.3v or 5v but what about other circuits, say in a car or on ...
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53 views

use sram as logic analyzer?

So I was thinking of buying a logic analyzer and found that a lot of the cheap ones are good to only a few mhz, and the microcontroller based ones can't have big buffers. So I was wondering if I could ...
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51 views

Why signals occupy small portion after being scaled and how to change it?

I am a newbie and try to understand why signals watched on logic analyzer shrink on screen when resolution is changed (as on the pics) so that they occupy a small region on the screen? It'a a ...
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252 views

What kind of serial communication is this?

I am trying to reverse engineer a serial communication between to microcontrollers (1 device & 1 microcontroller on a board). One MCU validates the other MCU and I want to crack the validation and ...
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92 views

Logic analyzer not shown signal

Good day. I am trying measure signal on ISO 9141 K-line - bidirectional serial link using logic analyzer. The device is Atmega based device with L9637 K-line driver chip. Problem is that, no signal ...
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1answer
173 views

Observing ethernet auto-negotiation packets using oscilloscope

In an answer to one of my previous posts seen here: Verifying 802.3 auto negotiation, @Zac67 mentions that by using an oscilloscope I could observe normal and fast link pulses that are sent in order ...
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97 views

Analyzing USB signals [closed]

I'm experimenting with HID lately. And I need to know more about the physical output signal of a USB keyboard. My goal in the end is to put a small data logger in between the USB-keyboard an a ...
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82 views

How to use Logic Analyzer and Event Viewer in Keil uVision with TM4C123GXL launchpad

I am using Keil uVision5 for programming TI launchpad TM4C123GXL with TIVA WARE Library. How to use Logic Analyzer and Event Viewer in Keil uVision ? While in a debug mode; I tried to set up ...
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86 views

Change waveform into binary in Saleae Logic Analyzer

I'm using this famous logic analyzer and I would like to know if I can change the waveform into binary, like I've done in this pic (white numbers).
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How to set up Keil Logic Analyzer to read specific pin?

How can I set the Keil uVision 5 Logic Analyzer so that I can read the status of a specific pin, example high or low? I have read the official docs here, however it does not say anything of the sort. ...
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74 views

Minimize Two bit Multiplication in Binary function

the input are X=(x1,x0), Y=(y1,y0). the output is Z=(z3,z2,z1,z0). the component: Z=X*Y . I got these simplified expressions by Karnaugh maps: (* = AND / + = OR / ~ = NOT ) z3=x1*x0*y1*y0 z2=x1*(...
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169 views

incorrect i2c frequency?

I am using an ATTiny88 MCU as master over an Si4012 slave. The MCU is running code produced by Arduino IDE. Connecting a logic analyzer to the SCL and SDA lines produce an output as below - second ...
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987 views

How to successfully trigger an ILA core in Vivado

I am trying to debug my VHDL project in Vivado 2014.03 on a KC705. My project consists of multiple VHDL modules implemented as custom IP cores, which are connected in a block design. I selected <...
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1answer
45 views

Help me add outputs from a two 3 to 8 decoders

I have built two 3 to 8 decoders, so that I can get an octal output 0-7 from each. Now, I need to be able to add these outputs to determine wether a number is greater than 7 or not. I have tried to ...
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1k views

How do I analyze this UART signal?

I want to make the same signal like the following images using an Arduino Uno. But I can't find the baudrate of this signal. I calculated baudrate the same way as Wikipedia. But when I used the ...
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Should I get a multimeter to check size of voltage to avoid damaging a logic analyser?

I am looking into getting a Saleae logic analyser for a project to reverse engineer an electronic display and buttons for use with a RaspberryPi. I think it should be OK as I would doubt, by my own ...
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151 views

Find frequency from Logic Analyzer from MP Lab X

In my code, I have a counter that increments by one with a breakpoint so that I can see the result. My problem is, how do I find the frequency of the pink line. My original thought was to find the ...
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1answer
68 views

Is it feasible to use a logic analyser for debugging a proprietary dot matrix display and button panel for use with RaspberryPi

I have an internet radio which is not supporting the latest codecs. Details of the original radio: https://www.manualslib.com/products/Revo-Pico-Radiostation-2865277.html http://www.expertreviews....
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545 views

Reverse engineering 7 segment display

I ran into a problem with one of my hobby projects and at this point I need some help. I'm attempting to sniff the signals going into a 7 segment display and use them for a purpose. The display is a ...
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1answer
70 views

USBee AX PRO input level

I have a USBee AX Pro logic analyser with 8 digital inputs accepting 0 to 5v. I also have a bpt perla intercom. It's working with a 2 wires bus (only 2 wires between outdoor and indoor panels) ...
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1answer
47 views

Do you know of software for automatic waveform compliance checking? [closed]

do you know of any software which can be used to automatically check a measured waveform (from a logic analyzer/scope) against some specification? For example I measured some pulse with a logic ...
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1answer
314 views

Xilinx ILA to start recording after triger + Xnum clock cycles

I am trying to debug my system with Xilinx Integrated logic analyzer and there is only a limited number of samples (131,072) that can be captured after the trigger signal, whereas I need about 350,000 ...
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1answer
139 views

Cheap alternative to 3M IC clips?

I'd like to connect my logic analyzer to the address and data lines of a 6264 parallel SRAM chip on a PCB I'm working on. It's a 28-pin, .600 mil DIP package. I have a 3M test clip for a .300 mil ...
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437 views

Logic Analyzer shows voltage change in analog but not digital

While using a logic analyzer with analog voltage to test Digital Output Pin voltages on an Arduino UNO, I am seeing the expected digital output and analog output (HIGHs and LOWs for digital and 5V to ...
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1answer
473 views

Improving RS485 / UART slew rates

I'm trying to implement a half-duplex 1Mbps RS485 bus (1 master controlling ~8 motors). After facing occasional communication errors I've invested in a Saleae logic 4. The RS485 A/B lines probed ...
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156 views

How to control chip select and Load DAC signals for a DAC chip?

I have a DAC7643 (Texas Instruments) - 16-Bit, Dual Voltage Output DIGITAL-TO-ANALOG CONVERTER I have been mostly unsuccessful with controlling the CS and LDAC signals. I have simulated a circuit ...
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1answer
645 views

Using Logic Analyzer for SPI

I started my project of interfacing MicroSD Card with PIC32MX795F512L. To start with this first I made a program to test ...
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2answers
172 views

How to use logic analyzer?

I have a circuit on a PCB where I am using PIC microcontroller to connect with DS1307 via I2C. I am having trouble while programming it so I am planning to purchase a logic analyzer so that I can see ...
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1answer
227 views

NAK in CAN when programming stm32f407vg uC

I am getting NAK error in CAN communication. Not really sure why, also frame itself is quite strange as in program I am sending different things. I have got two devices and therefore I monitor 4 ...
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166 views

Combining 8 digital signals

I am building a 8 channel 50MHz PC based logic analyzer to learn a bit about digital design. I am currently having trouble at the trigger portion of it, more precisely generating the signal that will "...
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1answer
118 views

General purpose cpu as logic analyser better / worse than dedicated FPGA implementation

This question relates to building a cheap but capable logic analyzer. I had the idea of using an x86 cpu that was running a program that could fit in the fastest cache that would just read data from a ...
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1answer
858 views

UART as logic analyzer?

I'd like to reverse-engineer a certain 2-wire digital circuit. I'm looking for the cheapest possible logic analyzer. I don't know the exact frequency of the circuit, but it's sub-1MHz. (Likely in the ...
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2answers
91 views

Are there logic analyzers for large signals (5+ volts)?

I've used logic analyzers for <5V signals but I'm curious if there are analyzers for larger voltages. Since logic analyzers don't display analog levels, could you use a logic analyzer to check ...
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308 views

Bus sniffing on SSDs

Are there typical types of buses used on commercial SSDs that can easily be sniffed using commercial dedicated hardware such logic analyzers? Has anyone had experience sniffing on buses between the ...
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3answers
180 views

Sniffing a proprietary data line at 47.5V

I need to sniff the physical layer of a proprietary data line with a logic analyser, but my analyser is limited to 5V input. Unfortunately the line runs at 47.5V, which would fry everything. I ...
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174 views

Logic analyzer: multiple circuits, one ground

I will receive soon my first logic analyzer but I'm wondering something: There's only one ground on the analyzer. What if I want to measure at the same time two circuits with two separate power ...
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498 views

Debugging VGA signal

I have tried to use my Open bench logic sniffer to capture data from a VGA output. I'm pretty sure I understand how the waveform should look, but I not getting consistent data. It feels very shaky to ...
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1answer
277 views

Analyzing 4-pin data port to determine protocol

I have a Solar controller for my pool, it controls the pump and actuator for routing water onto the roof to heat it up, when required. The controller knows the pool and roof temperatures, as well as ...
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1answer
781 views

Quartus II - SignalTap II Getting the Period of Sampled Data

I am working on a VHDL project where I am trying to make an LCD controller. I have been trying to get the period of my scaled clocks using Signal Tap, however the time bar does not show the time ...
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1answer
255 views

Why I cannot see SPI signal properly with oscilloscope?

When I monitor a SPI bus with only one probe, I see such output when data is transferred. I know that I need to use a logic analyzer to monitor the SPI, but I wonder why I see such signal that looks ...
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2answers
889 views

5 V to 12 V transceiver chip / hardware

I am looking for a way to connect my logic analyzer (an inexpensive Saleae which is intended for 1.8-5V targets) and a couple of other pieces of analysis equipment to a digital source with signals in ...
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2answers
6k views

How to use USBee AX logic analyzer under Linux?

I've got clone of USBee AX logic analyzer, to play with one and see if I need a device of such type at all. Unfortunately, I haven't found any Linux software that supports one. I have tried Sigrok, ...
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4answers
4k views

Using Pickit3 as a logic analyzer

I need to sniff some legacy SPI hardware and at hand have a Pickit3 and lots of PIC18F2550/4550. While there is no project out there that builds a logic analyzer out of a PIC18F2550/4550 (I will be ...
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7k views

AVR interrupt service routine not executing as fast as expected (instruction overhead?)

I'm developing a small logic analyzer with 7 inputs. My target device is an ATmega168 with a 20MHz clock rate. To detect logic changes I use pin change interrupts. ...
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2answers
4k views

RS 232 serial sniffing

We have a task in hand to sniff a RS232 protocol in a certain industrial automation setting (we have been asked to do this legally by the manufacturing company itself). We are planning to send a ...
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1answer
497 views

Open bench logic sniffer Not working

I am using my openbench logic analyser for the first time in a real project. I am not getting valid captures though. I have the latest client off dangerous prototypes website they recommend for mac. ...
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2answers
599 views

Scanalogic DIY Logic Analyzer, Extending Sample Time

I just completed my build of the Scanalogic DIY logic analyzer. It's working great, but I am noticing something odd about it. This question will likely only make sense to someone who has used or built ...