Questions tagged [serial]

In serial communication data is transmitted as a sequence in time. Main advantage: much less wires needed. Main disadvantage: Higher bandwidth for the same throughput.

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80
votes
3answers
129k views

Difference between UART and RS-232?

Most of the time RS-232 and UART come together in serial communication theories. Are they both the same? From my readings I concluded UART is a hardware form of the RS-232 protocol. Am I correct?
23
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6answers
8k views

Serial protocol delimiting/synchronization techniques

As asynchronous serial communication is widely spread among electronic devices even nowadays, I believe many of us have encountered such a question from time to time. Consider an electronic device <...
13
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3answers
22k views

UART receiver clock speed

I was trying to understand UART fundamentals.It is understood that It is an asynchronous communication protocol and hence the TX and RX clocks are independent of each other The data reception is ...
5
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2answers
5k 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 ...
0
votes
1answer
198 views

deserializing high speed data

I am trying deserialize data that come out of a LM98640 into 14 bits words: Attached you can find a figure of the signals out of the LM98640. http://www.ti.com/lit/ds/symlink/lm98640qml-sp.pdf (...
38
votes
8answers
35k views

How to resolve I2C address clashes?

I want to connect multiple I2C slave devices to a micro controller all on the same set of pins but the I2C devices all share the same address. The addresses are fixed in the hardware. Is there any ...
8
votes
4answers
15k views

AC-coupling capacitors for high-speed differential interfaces

Can you explain me why and where I should put AC-coupling capacitors (usually around 0.1uF) on high-speed (1...5 GHz) differential serial interfaces (like SerDes for Gigabit Ethernet SFP modules)? ...
9
votes
6answers
13k views

Resistors in series with Tx and Rx

I'm making my own board and using an ATmega 328 with the Arduino bootloader. I have a DIP switch to select either an FTDI chip (for programming) to be connected to the ATMega's Rx and Tx, or a GPS ...
9
votes
1answer
5k views

MIDI IN : many circuits

I'm building a MIDI IN to serial port RX cicruit (for Raspberry Pi, or Arduino, or anything else...) using a 6N138 optoisolator. But I find many different circuits, I don't know why there are so ...
4
votes
2answers
316 views

How does this PIC board achieve RS-232 communication without a line driver?

All the develooment boards I have seen yet with serial communication support usually have MAX232 line trasceiver. However, I have come across this Olimex PIC-LCD development board that does not have ...
3
votes
3answers
2k views

Serial Output returns wrong ASCII

I am using a FTDI cable and connected it with my mac. I can connect successfully with my serial terminal on my mac via the cable and can input text on my keyboard to be transmitted to the AVR. When ...
9
votes
6answers
10k views

Good RS232-based Protocols for Embedded to Computer Communication

I'm working on a project that involves a good bit of data communication between a remote Arduino and a computer. The wireless connection is through a pair of XBees, so we have a RS232 link between the ...
18
votes
9answers
12k views

Ideal WiFi to Serial (or SPI) bridge?

What are some recommendations on an ideal WiFi to Serial bridge? My ideal qualities would be: Simple connectivity, SPI or Serial Reasonable fast speed, at least 1mbit/sec ideally (though probably ...
11
votes
3answers
13k views

Can the Arduino be used to “spy” on a UART connection between two devices?

I have a need to install an Arduino (actually just the IC) into existing hardware to enhance functionality. What I would like to do is connect the Arduino so that it "spys" on the I/O lines between ...
6
votes
4answers
16k views

How do I hook up an LED across the tx pin on my Atmega328?

I've built a standalone Arduino and upload sketches via this method From Arduino to a Microcontroller on a Breadboard. I would like to hook up an LED across TX like on the Arduino board, so I simply ...
2
votes
2answers
31k views

Arduino Uno RX/TX pins

The Arduino Uno has one main controller and one controller serving as USB-to-serial interface. The RX/TX pins of the main controller are directly connected, via 1k resistors, to some pins of the "...
5
votes
2answers
268 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 ...
2
votes
1answer
6k views

Serial Adder vhdl design

I've a design problem in VHDL with a serial adder. The block diagram is taken from a book. Since i'm not skilled enough in design with clock (except some silly flip flop i've found on the web, and ...
5
votes
2answers
10k views

Arduino Uno R3 hardware serial: peripheral interfering with the USB/Serial-converter?

I like to use the hardware serial port (pin 0 RX and 1 TX) to connect a bluetooth module. Internally these pins are also ...
4
votes
5answers
7k views

Ethernet RJ45 interfacing with microcontroller

I am working on a project, (still in the nascent stage) where I have to implement a serial communication interface and an Ethernet interface. I tried to find out as much as I can and got the following ...
4
votes
2answers
2k views

Cascading several SPI devices

Is it possible to cascade several different ICs on the same data line, in order to use less CS pins, by tying the digital output of each to the digital input of the next? I am familiar with this ...
3
votes
1answer
962 views

Advantages of parallel over serial connections

As far as my understanding goes, parallel data connections are faster than serial at the same frequency. However, when you increase the frequency in parallel you start getting bits 'cross-talking' and ...
2
votes
3answers
853 views

Arduino Razor IMU with Serial.write(id, 2): Can't have 2 parameters

I downloaded the Razor IMU source code last night from Razor AHRS. This code uses exactly the sensors I need and would solve the problem I have currently (I hope). The only problem is that on line 535 ...
1
vote
2answers
21k views

Connecting GSM SIM900A module with Ardunio

I have bought an SIM900A Mini V4 GSM module. Here is the module, I want to configure with arduino to send and receive SMS. Do I have to connect TXD of this module--Tx of Arduino & RXD of this ...
0
votes
1answer
1k views

STM32: Manchester coding bit banging implementation problem

I want to use Manchester Coding for my DALI Master-slave project. I am using two boards for this project, one is STM32E407 and the other is STM32F3Discovery. As an initial step, I want to test for ...
0
votes
1answer
2k views

Problem connecting UART Wifi Module to PC

As refereed to my old question ( Connect UART WiFi module to PC ) which has been solved that days, I have a UART Wifi module ( this one ) and unfortunately I have problem again ! The point is, this ...
19
votes
3answers
50k views

How to read serial data from oscilloscope

I have a microcontroller (PICAXE 20X2) and a pot meter. I programmed the micro so that it sends any change of pot meter to serial port of PC. Obviously it is a 8bit ADC. Now the interesting thing for ...
22
votes
5answers
8k views

Why do people use AT commands in serial communication?

I need to know why people in embedded systems use AT commands? When I have asked people say that it is a standard. So my question is: What does "AT" means? Why do people keep saying it's a standard?
15
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2answers
36k views

How does TTL serial work?

I've been trying to find a good description of the TTL serial "standard" without much luck. I understand that serial transmit (TX) and receive (RX) lines idle high (at VCC) and that they drop to ...
17
votes
1answer
10k views

With shielded twisted pair cable, do you ground one end, both ends, or neither ends of the shield

I've got a project coming up that's to be doing RS-485 communications over shielded twisted pair cable. The project will involve cable length runs of many 10s of ft and the cables will probably have ...
9
votes
2answers
3k views

How to make a fingerprint scanner (UART, Serial) for a headphone jack on Android?

Square up reads magnetic stripe cards through headphone jack on both Android and iOS. I want to capture fingerprints on an Android phone. Can I develop a hardware to capture fingerprints in the same ...
6
votes
2answers
6k views

Serial (UART) communication

I just have a few general questions that those with more experience could easily answer. I am working with an arduino, and interfacing with various devices such as the PC that I use to write the ...
2
votes
6answers
5k views

Low cost simple communication between two microcontrollers

What tradeoffs and connection options are there in low cost bidirectional communication between just two microcontrollers? In this case: Master/Slave relationship, bidirectional data flow Distance ...
14
votes
6answers
50k views

Max Serial Cable Length?

What is the maximum length of serial cable I can use, to connection work properly? Is length of serial cable in connection with baud rate? I am using about 5 meter cable at speed 38400 bauds and RS232 ...
6
votes
3answers
14k views

Serial to USB adaptors - types and problems

I have an electronic device (commercially available, which someone else made), which essentially consists of a series of photoelectric cells, going through a black box of electronics, and through to a ...
9
votes
3answers
26k views

Firmware & Circuit of ATtiny45 direct USB 2.0 Connection

I want to make my own modular USB device using an ATtiny45 that simply sends data to the PC over USB. I'm not reading data, so a single way ( ATtiny -> PC ) connection would be completely okay. I am ...
8
votes
3answers
3k views

MSP430 serial communication failing in cold weather

I have a product using the MSP430 microprocessor, which has been selling for a couple years now. One of the MSP430's jobs is to communicate over async serial to a low-power radio. With the onset of ...
3
votes
1answer
499 views

Reverse-engineering asynchronous serial protocol for EcoSmart Tankless Water Heater

I am trying to reverse-engineer the remote control protocol for my EcoSmart Tankless Water Heater. Unfortunately, the remote control device is no longer available for purchase, and the manufacturer ...
1
vote
4answers
10k views

How to connect Raspberry Pi to House Alarm Serial Bus (DSC Keybus)

I have a DSC 1864 House Alarm and I want to connect up my Raspberry Pi's GPIO to the Keybus (a serial data communication protocol used by the alarm). I would say my knowledge of electronics is novice ...
9
votes
2answers
730 views

How is the fact that the resistor used to limit the LED current dissipates some of energy addressed in lighting applications?

LEDs can't be connected directly to a source of power - only in series with a current limiting resistor. Which means that when the LED is powered some power is dissipated by that LED and some power is ...
6
votes
5answers
10k views

How does UART know the difference between data bits and start/stop bits? [duplicate]

I understand that it is common for a UART scheme to use 8N1, meaning 1 start bit, 8 data bits, and 1 stop bit. Something like this: 0xxxxxxxx1 Where 0 is the start bit, the x's are the data, and 1 ...
6
votes
3answers
17k views

What is the maximum acceptable baud rate error for RS-232 serial communication?

What is the maximum clock difference between a transmitter and receiver for error-free asynchronous serial communication?
3
votes
3answers
2k views

Data over power line in a car

I am trying to build a communications system for a car, for turning gadgets on or off. One idea was to parasite on power lines, but what kind of components and signaling could be used for this? I am ...
3
votes
3answers
4k views

UART Receiver Sampling Rate

I am trying to create a UART receiver in Verilog for my FPGA. I was following this guide http://www.fpga4fun.com/SerialInterface4.html According to it the standard practice for asynchronous ...
3
votes
3answers
646 views

Doubts on Implementing a Simple Protocol for XBee Comms

A system that I'm developing will use XBee modules for a point to point connection between a micro-controller and a PC. Data will only be sent only in one direction -Micro to PC and at 10-20fps. The ...
3
votes
2answers
5k views

Connect UART WiFi module to PC

I recently bought a UART WiFi module (this one) and configured it (wireless configuration method) with right SSID but wrong password (and I don't know what it is). The problem is that I can't reset ...
3
votes
2answers
740 views

Is it OK to have data lines and AC in the same multicore cable?

I need to provide the following over sections of 1m multicore cable, totaling around 15m. 240v AC 5v DC GND RX TX Will the AC cause problems for the Serial data?
2
votes
1answer
650 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 ...
2
votes
2answers
694 views

Serial Communication Rx ISR logic design

If im not wrong, an ISR is supposed to do minimal processing when it receives a data serially(via UART). Im planning on implementing such a protocol for communication between 2 systems via uart. This ...
1
vote
2answers
3k views

USB / Serial converter without FTDI Chip [closed]

First of all I want to mention that this question is related to my last question about USB connection. ( please note that this question is about a specific topic that my last question is not about, ...