This document discusses serial communication, including:
1) The advantages of serial communication over parallel communication for long distance communication due to lower wiring costs.
2) The differences between synchronous and asynchronous communication and between simplex, half duplex, and full duplex modes.
3) How start and stop bits are used to frame data for asynchronous serial communication and how baud rate and bits per second are measured.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
A Novel Architecture for Different DSP Applications Using Field Programmable ...journal ijme
This paper presents a reconfigurable processor for different digital signal processing applications. The performance of the proposed architecture has been evaluated by taking different dsp applications like Low pass filter, high pass filter, finite impulse response (FIR) filter and FFT module. We designed the architecture of the processor and realizing the architecture using adder, multiplier, delay unit and validate it in the FPGA, which show that the hardware scheme is feasible for practical application. The experimental results clearly reveal the novelty of the architecture for dsp applications. This paper investigates the potential use of FPGAs for implementing efficient “Reconfigurable Processor” for different dsp applications. The proposed processor is based on parallel re-configurable which is implemented on FPGA. FPGAs have become an important component for implementing these functions with respect to cost, performance and flexibility. The general purpose SPARTAN 3AN FPGA kit has been employed for developing reconfigurable processor, with all the coding done using the hardware description language VERILOG.
Orthogonal Frequency Division Multiplexing, OFDM uses a large number of narrow sub-carriers for multi-carrier transmission to overcome the effect of multi path fading problem. LTE uses OFDM for the downlink, from base station to terminal to transmit the data over many narrow band careers of 180 KHz each instead of spreading one signal over the complete 5MHz career bandwidth. OFDM meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates.
The primary advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions. Channel equalization is simplified. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate inter symbol interference (ISI).
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
A Novel Architecture for Different DSP Applications Using Field Programmable ...journal ijme
This paper presents a reconfigurable processor for different digital signal processing applications. The performance of the proposed architecture has been evaluated by taking different dsp applications like Low pass filter, high pass filter, finite impulse response (FIR) filter and FFT module. We designed the architecture of the processor and realizing the architecture using adder, multiplier, delay unit and validate it in the FPGA, which show that the hardware scheme is feasible for practical application. The experimental results clearly reveal the novelty of the architecture for dsp applications. This paper investigates the potential use of FPGAs for implementing efficient “Reconfigurable Processor” for different dsp applications. The proposed processor is based on parallel re-configurable which is implemented on FPGA. FPGAs have become an important component for implementing these functions with respect to cost, performance and flexibility. The general purpose SPARTAN 3AN FPGA kit has been employed for developing reconfigurable processor, with all the coding done using the hardware description language VERILOG.
Orthogonal Frequency Division Multiplexing, OFDM uses a large number of narrow sub-carriers for multi-carrier transmission to overcome the effect of multi path fading problem. LTE uses OFDM for the downlink, from base station to terminal to transmit the data over many narrow band careers of 180 KHz each instead of spreading one signal over the complete 5MHz career bandwidth. OFDM meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates.
The primary advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions. Channel equalization is simplified. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate inter symbol interference (ISI).
Performance analysis of Multiband - OFDM systems using LDPC coder in pulsed -...IDES Editor
In this paper, a combined approach where low density
parity check (LDPC) codes are used to reduce the complexity
and power consumption of pulsed orthogonal frequencydivision
multiplexing (pulsed-OFDM) ultra-wideband (UWB)
systems is described. The proposed system uses LDPC codes
to achieve higher code rates without using convolution
encoding and puncturing thereby reducing the complexity and
power consumption of pulsed-OFDM system. The LDPCpulsed-
OFDM system achieves channel capacity with different
code rates and has good performance in different channel
fading scenarios. The pulsed OFDM system is used where
pulsed signals could spread the frequency spectrum of the
OFDM signal. The performance of LDPC-pulsed-OFDM
system for wireless personal area networks (WPAN) is
analyzed for different UWB indoor propagation channels (CM3
and CM4) provided by the IEEE 802.15.3a Standard activity
committee. To establish this, a design of LDPC-pulsed-OFDM
system using the digital video broadcasting-satellite-second
generation (DVB-S2) standard and provide the simulation
results for the different code rates supported by LDPC codes
is presented.
Cooperative Communication for a Multiple-Satellite Networkchiragwarty
when it comes to space communication
networks, there are many different kinds of space vehicles
that need to communicate with each other, in space as well
as with ground terminals and air borne platform. Example:
Geosynchronous Earth orbit (GEO), Low Earth Orbit
(LEO) satellites and UAVs. There is an ever growing
demand for higher data rates and minimal redundancy, with
satellites and various space platforms travelling at high
speeds relative to each other and relative to the ground
establishing such links can prove to be a real challenge
when Doppler Effect and line of sight (LOS) can play a
significant role in SONET timing and synchronization. As
the number of users grows the space communication links
need to address several types of coding and modulation.
This paper analyzes the use of cooperative communication
techniques for point-to-point and point-to-multipoint
communication links. To this end we start with a simplified
single relay model and proceed to analyze the multi-node
scenarios. We will then apply the amplify-and-forward,
decode-and-forward and coded cooperation protocols to the
best case scenario to compute the efficiency and
synchronization of the link. The single relay and multi-node
scenarios are evaluated on the basis of the signal to noise
(SNR) power received and inter channel interference (ICI).
The intention is to demonstrate the theoretical performance
by simulating outage probability versus spectral efficiency
for different relaying protocols. Subsequently we will show
the effect of cooperative communication on bandwidth
utilization for mobile satellites and space platforms.
A low dropout (LDO) voltage regulator with high power supply rejection ratio (PSRR) and low
temperature coefficient (TC) is presented in this paper. Large 1μF off-chip load capacitor is used to
achieve the high PSRR. However, this decreases the gain and pushes the LDO’s output pole to lower
frequency causing the circuit to become unstable. The proposed LDO uses rail-to-rail folded cascode
amplifier to compensate the gain and stability problems. 2nd order curvature characteristic is used in
bandgap voltage reference circuit that is applied at the input of the amplifier to minimize the TC.
The characteristic is achieved by implementing MOSFET transistors operate in weak and strong
inversions. The LDO is designed using 0.18 μm CMOS technology and achieves a constant 1.8 V output
voltage for input voltages from 3.2 V to 5 V and load current up to a 128mA at temperature between -40 °C
to 125 °C. The proposed LDO is targeted for RF application which has stringent requirement on noise
rejection over a broad range of frequency.
Qualitative Analysis of Darlington Feedback Amplifier at 45nm TechnologyjournalBEEI
The transistors are the key element of present communication system having high data rate. Some applications need high gain by using very low frequency, and then transistors are used. Amplifier is the key element in many applications of present high data rate communication system such as low noise amplifier (LNA), broadband amplifier, distributed and power amplifier. The Darlington pair amplifier is analyzed for high frequency performance and related effect of bandwidth. Broadband feedback Darlington pair amplifier is designed with enhanced gain, bandwidth and slew rate. This paper presents the comparison of single stage and three stage feedback Darlington feedback amplifier with reference to gain, bandwidth and slew rate. This paper is simulated on cadence analog design environment at GPDK 45nm technology. This paper shows that increase in gain, bandwidth and slew rate of three stage Darlington feedback amplifier can show better stability over the single stage Darlington feedback amplifier.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Data Communication & Computer Networks: Multi level, multi transition & block...Dr Rajiv Srivastava
These slides cover the fundamentals of data communication & networking. It covers Multi level, Multi transition and Block codes which are used in communication of data. It is useful for engineering students & also for the candidates who want to master data communication & computer networking.
Performance analysis of Multiband - OFDM systems using LDPC coder in pulsed -...IDES Editor
In this paper, a combined approach where low density
parity check (LDPC) codes are used to reduce the complexity
and power consumption of pulsed orthogonal frequencydivision
multiplexing (pulsed-OFDM) ultra-wideband (UWB)
systems is described. The proposed system uses LDPC codes
to achieve higher code rates without using convolution
encoding and puncturing thereby reducing the complexity and
power consumption of pulsed-OFDM system. The LDPCpulsed-
OFDM system achieves channel capacity with different
code rates and has good performance in different channel
fading scenarios. The pulsed OFDM system is used where
pulsed signals could spread the frequency spectrum of the
OFDM signal. The performance of LDPC-pulsed-OFDM
system for wireless personal area networks (WPAN) is
analyzed for different UWB indoor propagation channels (CM3
and CM4) provided by the IEEE 802.15.3a Standard activity
committee. To establish this, a design of LDPC-pulsed-OFDM
system using the digital video broadcasting-satellite-second
generation (DVB-S2) standard and provide the simulation
results for the different code rates supported by LDPC codes
is presented.
Cooperative Communication for a Multiple-Satellite Networkchiragwarty
when it comes to space communication
networks, there are many different kinds of space vehicles
that need to communicate with each other, in space as well
as with ground terminals and air borne platform. Example:
Geosynchronous Earth orbit (GEO), Low Earth Orbit
(LEO) satellites and UAVs. There is an ever growing
demand for higher data rates and minimal redundancy, with
satellites and various space platforms travelling at high
speeds relative to each other and relative to the ground
establishing such links can prove to be a real challenge
when Doppler Effect and line of sight (LOS) can play a
significant role in SONET timing and synchronization. As
the number of users grows the space communication links
need to address several types of coding and modulation.
This paper analyzes the use of cooperative communication
techniques for point-to-point and point-to-multipoint
communication links. To this end we start with a simplified
single relay model and proceed to analyze the multi-node
scenarios. We will then apply the amplify-and-forward,
decode-and-forward and coded cooperation protocols to the
best case scenario to compute the efficiency and
synchronization of the link. The single relay and multi-node
scenarios are evaluated on the basis of the signal to noise
(SNR) power received and inter channel interference (ICI).
The intention is to demonstrate the theoretical performance
by simulating outage probability versus spectral efficiency
for different relaying protocols. Subsequently we will show
the effect of cooperative communication on bandwidth
utilization for mobile satellites and space platforms.
A low dropout (LDO) voltage regulator with high power supply rejection ratio (PSRR) and low
temperature coefficient (TC) is presented in this paper. Large 1μF off-chip load capacitor is used to
achieve the high PSRR. However, this decreases the gain and pushes the LDO’s output pole to lower
frequency causing the circuit to become unstable. The proposed LDO uses rail-to-rail folded cascode
amplifier to compensate the gain and stability problems. 2nd order curvature characteristic is used in
bandgap voltage reference circuit that is applied at the input of the amplifier to minimize the TC.
The characteristic is achieved by implementing MOSFET transistors operate in weak and strong
inversions. The LDO is designed using 0.18 μm CMOS technology and achieves a constant 1.8 V output
voltage for input voltages from 3.2 V to 5 V and load current up to a 128mA at temperature between -40 °C
to 125 °C. The proposed LDO is targeted for RF application which has stringent requirement on noise
rejection over a broad range of frequency.
Qualitative Analysis of Darlington Feedback Amplifier at 45nm TechnologyjournalBEEI
The transistors are the key element of present communication system having high data rate. Some applications need high gain by using very low frequency, and then transistors are used. Amplifier is the key element in many applications of present high data rate communication system such as low noise amplifier (LNA), broadband amplifier, distributed and power amplifier. The Darlington pair amplifier is analyzed for high frequency performance and related effect of bandwidth. Broadband feedback Darlington pair amplifier is designed with enhanced gain, bandwidth and slew rate. This paper presents the comparison of single stage and three stage feedback Darlington feedback amplifier with reference to gain, bandwidth and slew rate. This paper is simulated on cadence analog design environment at GPDK 45nm technology. This paper shows that increase in gain, bandwidth and slew rate of three stage Darlington feedback amplifier can show better stability over the single stage Darlington feedback amplifier.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Data Communication & Computer Networks: Multi level, multi transition & block...Dr Rajiv Srivastava
These slides cover the fundamentals of data communication & networking. It covers Multi level, Multi transition and Block codes which are used in communication of data. It is useful for engineering students & also for the candidates who want to master data communication & computer networking.
Comparative evaluation of bit error rate for different ofdm subcarriers in ra...ijmnct
In the present situation, the expectation about the quality of signals in wireless communication is as high as possible. This quality issue is dependent upon the different communication parameters. One of the most important issues is to reduce the bit error rate (BER) to enhance the performance of the system. This paper provides a comparative analysis on the basis of this bit error rate. I have compared the BER for different number of subcarriers in OFDM system for BPSK modulation scheme. I have taken 6 varieties of data subcarriers to analyze this comparison. Here my target is to reach at the lowest level of BER for BPSK modulation. That is achieved at 2048 number of subcarriers.
Comparing ICH-leach and Leach Descendents on Image Transfer using DCT IJECEIAES
The development and miniaturization of CMOS (microphones and cameras) in the last years have allowed the creation of WMSN (Wireless Multimedia Sensor Network). Therefore, transferring multimedia content through the network has become an important field of research. It transmits the recorded multimedia data wirelessly from a node to another to reach the Sink (base station). Thus, routing protocols make a big contribution in this process, because they participate in optimizing the node's resource usage. Since Leach protocol was designed only to minimize energy consumption of the network. The goal of this paper is to compare our protocol in tnansfering images with other Leach protocol descendants. By using the application layer, we applied the jpeg compression using the frequency domain on images before sending them to the network. In this paper, readers will find statistics concerning the lifetime of the network, the energy consumption and most importantly statistics about received images. Also, we used Castalia framework to simulate real conditions of transmission simulation results proved the efficiency of our protocol by prolonging the lifetime of the network and transmitting more images with better quality compared to other protocols.
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Let's dive deeper into the world of ODC! Ricardo Alves (OutSystems) will join us to tell all about the new Data Fabric. After that, Sezen de Bruijn (OutSystems) will get into the details on how to best design a sturdy architecture within ODC.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
1. Section 17.1
Objectives
Upon completion of this chapter, you will be able to:
List the advantages of serial communication over parallel
communication
CMPE328 Microprocessors Explain the difference between synchronous and
(Spring 2007-08) asynchronous communication
Define the terms simplex, half duplex, and full duplex and
diagram their implementation in serial communication
Serial Interfacing Describe how start and stop bits frame data for serial
communication
Compare the measures baud rate and bps (bits per second)
By Dr. Mehmet Bodur Describe the RS232 standard
Compare DTE (data terminal) versus DCE (data
communication) equipment
Describe the purpose of handshaking signals such as DTR,
RTS, and CTS
Describe the operation of a USART and use and 8251 IC
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 2
Section 17.1 Section 17.1
Basics of Serial Communication Simplex vs Duplex
Microprocessors are based mostly on 8-bit In Simplex Mode data flow Transmitter Receiver
is in one direction only.
registers. Thus, their fastest I/O is 8-bit In Half Duplex Mode data
parallel ports. flows in one direction, at a Transmitter 0 1 Transmitter
given time, Receiver
Receiver 1 0
But, wiring cost of a long distance A protocol and switches
connect the devices both to
communication is very expensive if you receive and also to transmit.
carry 8-wires. In Full Duplex mode,
transmitted data and
Remedy is to transfer data serially in bits received data goes Transmitter Transmitter
instead of in bytes or words. simultaneously through two Receiver Receiver
channels.
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 3 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 4
2. Section 17.1 Section 17.1
Asynchronous Transmission
Asynchronous vs Synchronous
How can the receiver get each data bit when it is
Start and Stop Bits
delivered by the transmitter? Start bit is required to synchronize the internal
In synchronous transmission an explicit clock clock of receiver.
signal describes the instants of valid data. Stop bit is required to test the clock frequency.
A single data bit is sent at each clock.
Only DATA is transmitted, internal clock is
generated locally. Voltage levels are 0 and 5V (TTL signal)
Minimum three signal lines required for full duplex,
Receive-DATA, Transmit-DATA, and CLOCK. TTL DATA
In asynchronous transmission clock is derived internal
using a-priory parameters and a start bit. clock
Start D0 D1 D2 D3 D4 D5 D6 D7 Stop
Transfer rate known, internal clock starts to pulse with 0 1 0 1 0 0 1 1 0 1
the start bit, at the known transfer rate. Internal clock stops with the time
Internal clock starts Bits are sampled at
Ony two signal lines required for full duplex the rising edge of stop bit. If Stop bit is not
with the start bit. high, it gives framing error.
Receive-DATA and Transmit-DATA the internal clock
bit#: 7 6 5 4 3 2 1 0
Data is 01100101b =65h. It is ASCII “e”
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 5 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 6
Section 17.1 Section 17.1
Computers may be Asynchronous
connected to
eachother at COM
port or TTL signal
Communication System Data Transfer Rate
levels as well. 1488 and 1489 COM port
CPU BUS
MODEM
Transmit
DRIVER
Transmit
Both devices shall know the data transfer
System UART Phone Line
Bus rate of the communication to synchronize
Receive Receive the internal clocks correctly.
TTL
Level Signals
RS232
Level Signals
Data transfer rate is measured in BAUD
Baud = bit/second
Phone BUS
Telecommunication
Media MODEM
DRIVER
CPU
(including start, stop, data, parity etc.)
Transmit UART
Transmit System
Bus
kilo Baud = 1000 Baud. (not 1024 Baud)
Receive Receive Mega Baud = 1000 000 Baud
RS232 TTL
Level Level
Signals Signals
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 7 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 8
3. Section 17.1
Baud Rate Calculations Packet transmission time
If each bit takes T seconds,
the baud rate is B= 1/T. If a system sends a packet of 50 bytes at
Standard Baudrates are
150, 300, 600, 1200, 2400, 4800, 9600, 19200, etc. 1200 Baud, using 8-data, no-parity, one
Baudrate tolerance for a10-bit frame is 5%. stop bits, what is the transmission time of
Example: T=209μs B= 1/T = 4785 Baud the whole packet:
it is 4800 Baud within 5% tolerance. 1-byte frame is 1-start + 8-data + 1-stop bit
one frame period = 10 bits/byte.
T
packet is transferred by 50 x 10 bits = 500 bits
on the serial communication line.
Tpacket = 500 bits / 1200 Baud = 0.417sec.
Start D0 D1 D2 D3 D4 D5 D6 D7 Stop = 417 milliseconds.
0 1 0 1 0 0 1 1 0 1 time
bits 7 6 5 4 3 2 1 0
the transmitted data value is 01100101 b = 65h =‘e’
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 9 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 10
Section 17.1 Section 17.1
RS232 Socket Pins Handshaking Signals
Recommended standard
describe two kind of sockets. DTE DCE Modem-Terminal handshaking signals:
TxD 2 TxD 2
DTE: Device Terminal Equipment. RxD 3 RxD 3
Device status signals
Computers, Terminals, etc.
GND 7 GND 7 DTR: Data terminal ready (DTE is ok.).
DCE: Device Communication Equipment DSR: Data Set ready (DCE is ok.)
Modem (modulator-demodulator).
Equipment connections: Flow control signals
DTE DTE RTS: Request to Send (DTE sends char.)
DTE is connected to DCE TxD 2 TxD 2
without crossing. RxD 3 RxD 3 CTS: Clear to Send (DCE accepts RTS)
DTE is connected to DTE GND 7 GND 7
cross-wired.
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 11 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 12
4. Section 17.4 Section 17.4
UART 8251 8251 UART Device
Register addressing
8251 USART
A processor may transmit/receive data in ~CS C/~D=00 (data) TXRDY
serial format without any extra hardware. writes to the transmit buffer D[0..7] TXE
~TXC
But it costs to the processing time of the reads from the receive buffer TXD
RXD
processor.
~CS C/~D=01 (control) RESET
RXRDY
A UART (Universal Asynchronous Receiver Transmitter) is writes to the CLK
~RXC
SY/BR
a hardware device that shifts out data bits mode register right after a reset. C/~D
DSR
to transmit a data byte, and also shifts-in command register after mode is ~RD
~DTR
~WR ~CTS
data bits to receive a data byte. written. ~CS ~RTS
reads from the status register.
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 13 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 14
Section 17.4 Section 17.4
8251 system bus connection 8251 Clock Signals
8251 USART CLK is system clock input
TXRDY 8251 USART
Data buffer D[0..7] D[0..7] TXE Transmit TXC and RXC are transmit-receive TXRDY
Clock
address is 308h ~TXC
TXD serial
clock inputs. D[0..7] TXE
~TXC
data There are three baudrate factors
Control/Status RXD TXD
RXD
RXRDY Receive divide by 1, 16 and 64.
address is 309h, RESET RESET ~RXC Clock
Example. Find RXC oscillator frequency RXRDY
CLK CLK RESET ~RXC
TXRDY and A0 C/~D
SY/BR Clock
Generator
for 1200 Baud operation with baudrate CLK
SY/BR
DSR factor 1/64. C/~D
RXRDY are for ~IOR ~RD
~DTR modem DSR
~IOW ~WR Solution: fRXC =1200*64 Hz = 76.8 kHz. ~RD
interrupted Address ~CS
~CTS
~RTS
handshaking
Example: What shall be the baudrate ~WR
~DTR
~CTS
Decoder ~308h – ~309h
operation. factor for 4800 Baud operation if RXC is ~CS ~RTS
connected to 19.2 kHz ?
Solution: 19.2kHz/4.8kHz = 4, 1/4
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 15 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 16
5. Section 17.4 Section 17.4
8251 mode/control settings
8251 Reset Sequence
8251 USART
Mode Register format for asynchronous mode:
and status bits
b7 b6 = { S2S1: nr.of stop bits 00: invalid / 01:1stop / 10: 1.5stop / 11: 2stop },
8251 reset sequence is b5
b4
= { EP: parity type 0: odd / 1: even },
= { PEN: parity enable 0: no-parity-bits / 1: parity-bits-present },
write three successive zeros to control address to b3 b2 = { L2L1: nr.of data bits 00: 5-bit / 01: 6-bit / 10: 7-bit / 11: 8-bit },
b1 b0 = { B2B1: baud rate factor 00: sync-mode / 01: /1 / 10: /16 / 11: /64 }
assure writing a reset to the command register. Control Register format for asynchronous mode:
b7 = { EH: Enter hunt mode to search sync char 1: enable / 0: disable }
write command 40h to reset (reset chip) b6 = { IR: Internal reset 1: resets the 8251A }
b5 = { RTS: Request to send, 1: RTS-output-forced-to-low }
After the reset, 8251 expects mode settings. b4 = { ER: Error Reset 1: reset error flags PE,OE,FE }
b3 = { SBRK: Send break char 1: forces TxD low }
write the mode settings to control address b2 = { RxE: Receiver enable 1: enable, 0: disable }
b1 = { DTR: Data terminal ready 1: DTR-output-forced-to-low }
There after 8251 needs command settings. b0 = { TxE: Transmitter enable 1: enable, 0: disable }
Status Register format for asynchronous mode:
write command for command settings. b7 = {DSR 1: DSR pin is active (low)}
b6 = {SY/BD 1: sync-or-break char detected}
Now the device is ready for transmit and receive b5 = {FE 1: Framing error occurs}
b4 = {OE 1: Overrun error occurs}
operations b3 = {PE 1: Parity error occurs}
b2 = {TxE 1: Tx finished transmitting all data}
b1 = {RxRDY 1: Data-in buffer is full}
b0 = {TxRDY 1: Data-out buffer is empty}
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 17 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 18
Section 17.4
For the circuit 8251 initialization For the circuit with ports 8251 coding
with ports 308h, 308h, 309h enabling
309h enabling Mode Register 8251, write a code mainloop
b7 b6 = { S2S1: nr.of stop bits 00: inval./ 01:1stop / 10: 1.5stop / 11: 2stop }, .model small
8251, write a b5 = { EP: parity type 0: odd / 1: even }, a) to initialize it for 1200 .code ….
code b4 = { PEN: parity enable 0: no-parity-bits / 1: parity-bits-present }, baud when TXC ; reset 8251 ; read the port
a) to initialize it for b3 b2 ={ L2L1: nr.of data bits 00: 5-bit / 01: 6-bit / 10: 7-bit / 11: 8-bit }, connected to 19.2kHz, to
mov dx,309h mov dx,300h
1200 baud when b1 b0 ={ B2B1: baud rate factor 00: sync-mode / 01: 1 / 10: 16 / 11: 64 } transmit characters to a
mov al,0 in al,dx
TXC connected to Control Register DCE with 8-bit data, no mov ah,al ; save it
19.2kHz, to b7 = { EH: Enter hunt mode to search sync char 1: enable / 0: disable } parity, one stop bit out dx,al
transmit b6 = { IR: Internal reset 1: resets the 8251A } configuration. out dx,al ; send the char,
characters to a b5 = { RTS: Request to send, 1: RTS-output-forced-to-low } b) to read port 300h, and out dx,al ; wait if buffer is full
DCE with 8-bit b4 = { ER: Error Reset 1: reset error flags PE,OE,FE } transmit the value in mov al,40h mov dh,309h
data, no parity, b3 = { SBRK: Send break char 1: forces TxD low } serial format out dx,al wdataout
one stop bit b2 = { RxE: Receiver enable 1: enable, 0: disable } in al,dx ; status byte
b1 = { DTR: Data terminal ready 1: DTR-output-forced-to-low } ; set mode
configuration. b0 = { TxE: Transmitter enable 1: enable, 0: disable }
Status Register format for asynchronous mode:
mov al, 4Eh and al,01h
b) to read port b7 = {DSR 1: DSR pin is active (low)} jz wdataout
300h, and Mode register shall be 01001110b = 4Eh b6 = {SY/BD 1: sync-or-break char detected} out dx,al
b5 = {FE 1: Framing error occurs} ; set command ; now send character
transmit the value Control register shall be 00110011b = 33h b4 = {OE 1: Overrun error occurs} mov al,ah
in serial format mov al, 33h
b3 = {PE 1: Parity error occurs} mov dx,308h
handshaking b2 = {TxE 1: Tx finished transmitting all data} out dx,al out dx,al
to modem is receiver is disabled. b1 = {RxRDY 1: Data-in buffer is full}
enabled. b0 = {TxRDY 1: Data-out buffer is empty} ; continue looping
only transmitter enabled.
jmp mainloop
end
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 19 CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 20
6. Exercise
Solve the following two Final Exam
questions.
Final Fall 06
Final Fall 07
CMPE328 Spring 2007-08 Dr.Mehmet Bodur, EMU-CMPE 21