Questions tagged [baudrate]

Often misused term, when "bit-rate" is meant.

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16
votes
7answers
4k views

How do some microcontrollers implement baud rates even though it uses crystal frequency not scalable to standard baud rates?

I just realized that the 8051 family uses 11.0592 MHz and its multiples so as to generate standard baud rates. But there are SoCs which use 15 MHz. How do they do this then?
14
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3answers
3k views

How do two UARTS know which baud rate to use?

I am reading about the standard protocol for UART and I think that if the receiving UART does not have any idea on what baud rate the data was transmitted, there would be lots of problems. If the ...
10
votes
3answers
19k views

High-speed computer interface with an Arduino

I'm planning a project with an Arduino that involves handling a lot of requests from a host computer, and the standard 115200 maximum baud over serial isn't sufficient. I'd like to be able to get ...
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 ...
8
votes
2answers
1k views

Does a baudrate in serial communication (USB or RS232) need to be exact?

In serial communication, does the baudrate mean we have to use the exact clock speed or is it a range of speeds that we can use? and if it's an exact value, how exact should it be ? for example, can ...
8
votes
1answer
161 views

Unexpected Atmega16 response over UART

Unexpected Atmega16 response over UART Brief problem summary I have flashed an Atmega16 with code that should result in the Atmega16 sending back whatever character I send to it via a terminal. I ...
7
votes
2answers
11k views

Is there any reason why using a baud rate of 31250 on an Arduino MIDI project could cause problems?

I have a 600 pulse per revolution optical encoder (and some other stuff) connected to an Arduino Uno (tried it on r2 and r3) through the interrupt pins 2 and 3. While waiting for a my MIDI jack to ...
7
votes
6answers
4k views

Symbol rate (baudrate) estimation

I am looking for a algorithm that can detect the rate of symbols in a base-band signal. The Gardner method is a way to cancel out the timing drift and synchronize the receiver to sender when the ...
6
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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?
5
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2answers
1k views

Baudrate of DS18B20

I'm trying to connect a DS18B20 to my Beaglebone Black. Now I wan't to determine the Baudrate but can't find it in the Datasheet of the DS18B20. In the internet I saw different ones (9600, 19200). ...
4
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5answers
4k views

Serial to USB converter

I have a DSP kit with a serial connection. Since, I am operating on my laptop, I do not have access to a serial port. So, I would require a Serial to USB converter How do I create a Serial to USB ...
4
votes
5answers
22k views

Baud rate vs. Bit rate

When we initialize a serial communication, we usually have to set the baud rate (e.g. 115200) I notice that many people assume that 115200 means 115200 bits per second. However, each baud(signal ...
4
votes
1answer
8k views

Is it possible to have any CAN baudrate?

Is it possible to have any CAN baud values? e.g. 507 baud If not, on what basis is the standard values are derived?
4
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2answers
9k views

How set the baud rate for serial communication in ATmega32u4

I have a teensy 2.0 board and am trying to use it to control this LCD through serial TTL. I got it to work fine with my Arduino uno and some sample Arduino code, but I want to do it with the teensy ...
4
votes
2answers
4k views

Baud-rate for 8051 Microcontroller

I will like to know if a baud-rate of 9600 is so fast for an 8051 MCU using an 11.0952Mhz crystal. Why? I have observed some inconsistency in the behavior of my MCU, in that when I send a set of ...
4
votes
2answers
746 views

Xbee not responding timely. Large delay between each transmission

I have prepared a setup for 2 Xbees one connected to the PC via XCTU and the other interfaced with Atmega 168. The terminal software will send 1 and the xbee with Atmega 168 will return 1. The code ...
3
votes
2answers
400 views

Max SPI data rate supported

This is probably relevant for all SPI compatible chips but I'm asking for the DRV8711 in particular. The data sheet lists the SPI timing requirements and I was wondering how to get the maximum data ...
3
votes
2answers
2k views

does PIC require MAX232 for uart?

Sorry for the stupid question but, I'm interfacing a PIC18f46k20 to an Atlas pH sensor module. Both are running on 3.3v. Must I use a max232 between or can the pic talk 232 directly to the module? ...
3
votes
3answers
2k views

Does Bluetooth range increase with lower baud rate?

I am using two Bluetooth dongles for an Arduino project of mine. I am only sending a single int over the connection so it does not need to have a high baud rate. If I use a baud rate of 1200 will ...
3
votes
1answer
30k views

Controller Area Network (CAN), high speed and low speed

Is the difference between high- and low-speed CAN only with respect to baud rate values? Is the CAN transceiver programmable for a range of speeds or is it fixed for a specific value? For example, can ...
3
votes
2answers
2k views

UART baud rate error tolerance

I have a question regarding the UART baud rate error tolerance, as the thread title indicates. First of all, I want to point to an excellent tutorial on clock accuracy: Maxim Integrated Tutorial I ...
3
votes
1answer
554 views

FT230X Baud Rate Aliasing

I'm using a FT230X UART, and I'd like to use it with a non-standard baud rate. I came accross this note, explaining that I have to modify the driver file, but even with this documentation I have some ...
3
votes
1answer
3k views

find TH1 in AT89s52 micro controller in serial communication

I want to establish serial communication between an 8-bit microcontroller, AT89S52, and a PC. I am using a crystal oscillator of 8 MHz frequency. For baud rate calculation I have used the following ...
2
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5answers
292 views

How can I be sure that a multi-bit-per-symbol encoding schema exists?

(I came up with this question when I try to understand bit rate and baud rate.) Suppose I have some data to transfer. And the data is binary encoded as a data amount of N bits. If I use 2 symbols to ...
2
votes
5answers
6k views

Nyquist theorem, seems wrong to me

For Nyquist theorem, for channels without noise the bit rate is: \$N=2B\log_2(L)\$ N= bit rate, B= bandwidth, L= number of levels Intuitively I say that it should be: \$N=B\log_2(L)\$ ...
2
votes
1answer
4k views

how do I change baud rate for bluesmirf without connecting to pc?

Hi I have the sparkfun bluetooth mate silver. I am trying to start working on control via bluetooth for my Arduino. Only thing is I need to set the baud rate for the bluetooth mate, all guides I can ...
2
votes
3answers
10k views

Baudrate Calculator

I need to know what the value of TH1 and TL1 should to set the baudrate of an 8051 controller to 115200 Hz. I'm using an ...
2
votes
1answer
721 views

Calculating the correct BAUD for the ATMEGA168A

What is the correct way to set the BAUD when programming an ATMEGA168A? The code below works fine, however I don't know exactly what to do in case I decide to work with a higher BAUD such as 9600: <...
2
votes
2answers
3k views

msp430g2553, how can I get a UART baud rate higher than 9600?

I have an msp430g2553 in its launch pad. I have tried using a baud rate of 19200 with the UART and I get gibberish. From what I have found, something with the launchpad or drivers limits the UART baud ...
2
votes
1answer
2k views

What are the considerations for choosing Bluetooth baudrate?

I have an Arduino UNO which will be using an HC-05 bluetooth module to connect to a program running on PC. Its baud rate can be configured from as low as 4800 to as high as 1382400. I know that there ...
2
votes
1answer
90 views

UART stop bit baud timing error

On PIC micro controller UART, Baud rate was set to 38400 (No parity,, 8 data bits), ...
1
vote
3answers
3k views

What difference does the clock make in synchronous vs asynchronous communication?

I am new to embedded programming and have very little knowledge in how digital/electronic system works, but I have been given a task to bring up USART communication between two chips. For that, I ...
1
vote
1answer
769 views

Why is the CAN bus always busy (microcontroller)?

I'm trying without success to perform CAN bus communication between an microcontroller and the host (my computer). My question does not depend on the microcontroller, but on the CAN Bus (classic CAN). ...
1
vote
1answer
2k views

STM32L0 Low power UART-receiver reads the wrong data at high baudrate after MCU waking up

I'm using a STM32L0 MCU for my project. The MCU has a Low-power Timer (LPTIM) for waking the MCU up from Stop-Mode, and a Low-power UART (LPUART) for both waking up the MCU from stop mode and receive/...
1
vote
2answers
518 views

Why is the data rate a function of the length of the transmission line?

The length of a transmission line is limiting the highest possible data rate on that line. Why are faster signals more likely to become corrupted on long transmission lines than on shorter ones, with ...
1
vote
1answer
62 views

MSP430 USB Module and Baud Rate Detection

I am working on a project which uses the USB module integrated into the MSP430F5529, specifically using the MSP-EXP430F5529LP development board from TI. I am using the USB API provided in MSPWare. ...
1
vote
1answer
351 views

Communication between different Baud rates [closed]

I am totally new to just about all of this, first off. I have two boards that I want to be able to communicate. Both are using half-duplex serial connection, but one is fixed at 4800bps, and the ...
1
vote
1answer
921 views

Can I connect a CAN node with 250 kbit/s to a CAN bus running at 500 kbit/s?

I'm trying to connect an automatic car gearbox which is using the CAN bus at 250 kbit/s to car with bus speed 500 kbit/s. Is it possible to have nodes with different speeds on the CAN bus? ...
1
vote
1answer
49 views

Transmission of serial data characters

On a serial data link characters are transmitted data rate of 9600 baud. if characters are 8 bits and there is one start bit and one stop bit per character, then what is the number of characters ...
1
vote
2answers
139 views

MSP430 Baud Rate Generation: Datasheet Discrepancy

My project is based around the MSP430F5529. From the MSP430x5xx family user guide: NOTE: Baud-rate settings quick set up To calculate the correct the correct settings for the baud-rate ...
1
vote
1answer
420 views

UART devices: Baud rates different by a factor

I have UART devices where I can chose various non-standard speeds, but none of them are matching. There are however some speeds, that are a multiple of the other device's speeds. For instance, I could ...
1
vote
1answer
325 views

Changing BaudRate in both sides simultaneously

Through the C# interface i want to change the baudrate, to do that ofcurse i have to change the baudrate in the other side which is MSP430 using CodeCompserStudio and to send an Ack to PC then I ...
1
vote
1answer
608 views

Renesas RL78 SPI Baudrate Change

I am using an Renesas RL78 and SPI to communicated with an SD card. I have the driver working using the single command Baudrate of 400kBaud when sending both commands and data. Of course, this is ...
1
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1answer
89 views

Why is the signal rate separated into three case?

The definition of signal rate is number of signal elements (timewise shortest unit) sent in 1s. The book says that the signal rate of all 1s or all 0s may be different from a data pattern of ...
1
vote
1answer
151 views

Absolute minimum delay required to process data across shift registers

In an effort to make my serial data processing faster, I attempted to use serial mode 0 with a system clock speed of about 3.686Mhz. Its clock comes from the ALE output of an unprogrammed at89S52 that ...
1
vote
1answer
144 views

UART works when I open minicom before starting UART

I am trying to send out large amounts of data at 115200 via UART. I have come across a rather strange problem. I am sending out data in the while loop of the MCU. The MCU is not doing anything else. I ...
1
vote
2answers
2k views

How to increase throughput of xbee?

I'm doing a project on live audio streaming through xbee. The baud rate we are using is 115200. Audio transmission works perfectly through wired UART connection. But when we performed wireless ...
1
vote
1answer
198 views

AVR Dragon: Debug Frequency?

I think of buying an AVR Dragon or an AVR JTAG ICE MKIII. But before I do this, I need to know what side effects the reduced debug frequency has on an ATMEGA328P while debugging. I make heavy use of ...
1
vote
0answers
71 views

How can I estimate the minimum baudrate for a given bitrate?

My circuit performs data acquisition at 250 samples/s, 24 bits/sample and transmit this information to the local host (PC) through a bluetooth module that implements the UART protocol. As far as I ...
1
vote
1answer
121 views

How does Nyquist bit rate formula relate Bandwidth, Signal Rate, and Bit Rate?

I know what each of Bandwidth, Signal rate, and Bit rate mean. But I am having trouble in their mathematical relationship with each other. I will use the notation of the textbook I am reading from (...