Questions tagged [serial-bus]

The process of sending digital data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.

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70 views

RS422 and RS485; full-duplex or half-duplex?

I have extensively used RS232 transceivers in many projects and have fairly good understanding of UART communication using RS232 transceivers. MAX232 and MAX3232. Now I have to build my understanding ...
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42 views

What is the difference between a multiplexed bus and a multi-master bus

The jargon of terms in bus architecture literature is half the difficulty in understanding it. At some places the term 'multiplexed' bus is used while at some other places 'multi-master' bus is used. ...
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74 views

Lack of 'determinism' in Ethernet bus

While reading this website, I found out tha there is lack of 'determinism' in the Ethernet network bus as compared to some other buses like 1553. What I understand is that Ethernet is a single master ...
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CAN Transciever kbps to Hz at TXD Pin

I am new to the CAN Bus and have designed an application example. The Transceiver I have chosen is TJA1044Gx. The transceiver data sheet says : I want to know if I have only Transceiver, Analog ...
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45 views

How would I place CAN termination resistors in a 3 ended configuration?

I have a project for which I have one central circuit board which has a can node on it, this central circuit board has three connectors on each of which a node could or could not be plugged in with a ...
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107 views

Maximum Switching Speed Chained 74HC595

I'm planning to use a set of daisy chained 74HC595s to control a set of 108 mosfets, 3 of them are geographically in the same area (couple of mm apart) and for the sake of modularity should each use ...
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123 views

RS485 vs RS232 similarity vs differences

I have used UART RS232 communication between MCUs extensively. Now I need to interface my STM32F407 MCU over RS485 bus with with devices. I have understood few things about RS485 but not-clear about ...
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495 views

Direct connection of UART serial port to USB type-C

in my project I have a USB type-C 3.1 2nd Generation (24 pins), which should provide 5V to a charge battery/battery system. In addition, there is a uC powered at 3,3V where the maximum voltage on GPIO ...
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77 views

How to select the most appropriate (serial) bus for controller?

In the context of a robotic project where different 'payloads' and/or robotics arms (end-deflector) should be mated mechanically with power, data and control connections support, I would like to ...
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1answer
123 views

What does it mean when i2c_smbus_read_byte() returns 0

i2c_smbus_read_byte() returns a negative value when there is an error in reading data. But what if it returns 0? Following is the code from adt7316-i2c driver ...
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99 views

How does this serial input DAC work?

This is the datasheet for 6379A: datasheet I looked at the timing charts, but I’m still having trouble figuring out how the IC treats the serial input. Apparently, SI is sampled at positive clock ...
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1answer
119 views

Daisy chaining I2C modules using CAT5 and P82B715

I'm planning to connect several modules over I2C with distances between modules ranging 30-180 cm. I understand that in order to avoid the degradation of the signal due to the capacity of the ...
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1answer
140 views

MAX485 suddenly drawing too much current and output voltage levels are not right

I have two PCB that I designed and they are made by a PCB manufacturer (so they are identical). They use a MAX485CSA to communicate but suddenly one of them is drawing too much current, on a normal ...
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614 views

How to find out whether serial standard is RS232 or TTL when stated as “serial(RS232/TTL)”

I am recently moving from C programming into automation engineering. I have learned about RS232 and TTL standards, and I understand that they are based on the same concept of serial communication, ...
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1k views

Switching RS-485 bus

As shown in the graph, I'm trying to use mcu-controlled switches to turn a segment of rs-485 bus on or off (so that only one segment is on at a time). I was considering analog switches but I'm not ...
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273 views

ESP32 AND CP2102 Serial data reading issue

I have a PCB on which i am taking a 5v - 1A DC power supply , and again providing 3.3v to ESP32 through AMS-1117 3.3v. Basically things are not working on when i solder the esp32 on my pcb but things ...
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91 views

Data transmission over up to 100 ft

I need to transmit data (less than 5Mbps) point-to-point over 100 ft. I prefer not using Ethernet due to the complexity. I can use low-scale FPGAs or similar chips if needed for functions like error ...
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175 views

2-wire MPU interface / 2-wire Serial Control Interface?

While reading datasheet of an audio codec IC, I got confused over the term "2-wire MPU serial interface". Is that just another term for I2C (just like TWI or TWSI) and they are fully compatible? And ...
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135 views

Avoid reboot of USB serial device when another USB device is inserted [closed]

EDIT 7/7/2018: Can't add an answer because this question is closed however there is an answer here. It is not a problem related to Windows only. The reset is caused by hardware behaviour, the ...
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70 views

Suitable 12VDC Communication protocol for untwisted unshielded long-ish wire length?

What would be a reliable and simple tranceiver interface/protocol for board to board serial communication at about 100ft. [9600bps or lower is fine.] The two-lead communication wiring cannot be ...
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60 views

Quantifying Eye Diagram for high-speed SERDES channel

I need help quantifying Eye Diagram. I have to quantify Eye Diagram at the end of my Thesis for my Serial Link channel. Viewing an Eye Diagram, I can say probably whether it is bad or good. But for ...
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2answers
316 views

One master to 32 slave pic microcontroller communication, bitbang

I'm trying to communicate with 32 microcontrollers (PIC 12f675). These are used to control 32 DC motors and 2 sensor for each PIC. So only two pins are left to communicate with master device. I want ...
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656 views

I2C bus extender

I am working on a project which requires a long I2C bus which can be long as 200m or more.I searched on the internet and found a chip nxp PCA9600.I would like to know is there any alternate for this ...
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298 views

Reliability of Serial IO Expander like MCP23S17

Background: I am doing a re-design of an existing system moving from HC11 base with memory mapped I/O to an ARM Cortex-M3 with serial SPI/I2C I/O (opto-isolated inputs and relay outputs). I/O access ...
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166 views

Serial communication protocol [closed]

I want to learn about the raw serial communication protocol (The one that uses the Rx and Tx pins of a microcontroller). I want to be able to send bits of data without using a microcontroller. How ...
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74 views

12 bit asyncronous USART using pic (rx)

I need to implement an asynchronous receiver USART. The length of the frame is 12 bits. I looked into implementing this with a pic 16F1455 but it only supports 8-9 bits: "Programmable 8-bit or 9-bit ...
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4answers
2k views

Decoding message data on this CAN bus

I am working with the CAN bus and need some help with decoding message data. Here is a sample of the data that I'm seeing on the CAN bus. ...
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1answer
709 views

Where is the benefit in SQI parallel interface over SPI? Parallel vs. serial

Microchip is offering a number of serial SRAM chips with a communication protocol called SQI which is similar to SPI but with 4 parallel bits written at each CLK toggle. If you can spend the extra 3 ...
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929 views

Is RS-485 a suitable physical layer for Atmega chips in a home monitoring situation?

I am intending to build some Atmega based home monitoring chips. I want to monitor temperature, humidity, and current levels. Current level monitoring would be done with an inductive pickup on AC ...
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2answers
606 views

Why would credit card reader over audio jack not work on some devices?

This isn't a troubleshooting question, it's purely to satisfy my curiosity... MagTek makes a product called the uDynamo credit card reader that uses the audio channel on android devices as a ...
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2answers
278 views

usb to rs232 serial communication

I have to configure my rs232 to device(transmitter) using usb to serial communication. I have tried with usb to rs232 cable and connect the transmitter 6 pins to the db9 connector but it did not work. ...
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472 views

LCD interfacing Issues: Embedded Systems

Hobbyist tend to use parallel communication for interfacing with an LCD and all the libraries are for a specific type of microcontroller (Arduino or AVR) or LCD. But, for a design engineer, it is ...
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790 views

FT232RL USB to serial : 5V or 3.3V set by jumper

I've just bought a cheap FT232RL USB To serial adapter (EAN: 0680004529143). It does not come with a manual and the short description simply mention: USB power supply, can choose 5V or 3.3V ,set by ...
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266 views

Tool or method to listen to a custom RS485 bus traffic

How do I listen to a CFLink bus for data? The said bus was implemented on top of RS485. I've tried hooking it up using an RS485 to serial adapter and RealTerm but I've got nothing returned even though ...
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4answers
273 views

Device discovery on simple bus

I am currently facing following problem: there is a system, which consist of one master device and some number of slave devices (all those devices have tiny MCUs). They communicate with some custom ...
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2answers
40 views

How to feed 2-state voltage into PC?

I have a simple circuit that generates +5V under normal conditions but goes down to 0 when something is wrong. I need to feed this voltage into a PC (running Ubuntu) and write a program to monitor the ...
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1answer
1k views

Quad SPI - Serial or parallel [closed]

Question: Is Quad SPI really a serial interface, a parallel interface or both? The image below depicts that independent databyte may not be able to send over individual lines (I see databits spread ...
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2answers
241 views

Standard cables for modbus protocol

What are the standard cables I can use for modbus protocol? lease add the price details if anybody knows
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If serial ports are asynchronous, why do they have an SCL line?

For instance, this tutorial has these two seemingly contradictory quotes: Because serial ports are asynchronous (no clock data is transmitted), devices using them must agree ahead of time on a data ...
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448 views

What does this bus signal representation mean?

Often, when looking at digital system signal plots over time there are these graphs with two parallel lines that often "swap" place. I am wondering what precisely they represent? I noticed they ...
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3answers
371 views

Are there standards for digital sensor links?

Following this question, @curious_cat had more questions in comments that deserve a proper Q here: Is there any standard encoding that has evolved on the digital encoding side? Just as 4 to 20 mA ...
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2answers
754 views

Why are there sensors that encode their readings as serial sequence of PWMs?

This is a comment of @CuriousCat, but I think it deserves the attention of an actual question: The sensor used in the original question outputs a serial PWM-style signal like this: What's the ...
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1answer
73 views

How do I know if the serial cable is plugged in the right way?

I recently got a LeddarTech Leddar One rangefinder, which has a UART serial connector. I'm used to boards denoting the pinout directly next to the pins, but the only distinguishing mark on this board'...
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523 views

SERIAL/USB Game Controler Reverse engineer

I recently acquired a Logitech Wingman Formula Force from a thrift store. This controller is marketed as USB or Serial port. By default the controller ships with a native serial connector, but then ...
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4k views

Why is the serial connection faster than the parallel connection? [duplicate]

As a software developer the concept of parallel processing usually meant faster processing because it meant things don't have to wait for the other processes to finish if they don't need to. So how ...
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1answer
428 views

18bit Serdes - Xilinx Spartan6

In a project with FPGA stereo vision I use two MT9V032 cameras. The cameras are connected as in the application example in the data sheet. In stereo output mode the data length is 18bits long. There ...
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1answer
763 views

Physical wiring architecture for a CAN Bus

I want to wire a CAN bus for multiple motors(BLDC) in robotic arm. I am building out my motor such that they have a controller and a CAN transciever built in. There will be upto 6 motors with the ...
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1answer
639 views

SN65176 RS485 contention

I am transmitting RS485 via: Mono application -> Linux USBTTY device -> RS485 adapter with an added 100R terminator -> ~1m CATV -> SN65176 with an added 100R terminator -> PIC. Via debugging I am ...
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1k views

Start Bit and Idle Data Line?

I am learning the Serial Communication without much EE background: The article says: The start bit is always indicated by an idle data line going from 1 to 0, while the stop bit(s) will ...
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1k views

Max 485 auto transmission

i am using Max232 and max485 to convert the RS232 pc data to RS485. I got a circuit using these ICs with a transistor and some resitor. circuit is such that RE and DE are short together and tied to ...