Technical Review : Logisim variants( ITA, IITD, evolution, cs3410 )

In the previous article about logisim software review we have almost seen all the aspects of the original logisim software, and now we will see some variants of logisim which have evolved due to logisim being open-source( one of the most beautiful feature of an open-source software is evolution, development by other people than the main author )

So here we will see all the available variants and their plus points of being a logisim variant, the links of the software, I am not providing here but you can comment down, if you don't find it on internet, but there is 99% chance that if you write their proper name and google search it you will definitely find it.

So, first of all we have Logisim Italian version(Logisim-ITA.jar), well it is not italian only, but also has english language, it is compiled with the most recent version of JAVA and hence receives updates, patches and stays almost updated and can be run on any modern OS without fail.

 The most noticeable feature of this variant is, it has all the 74xx libraries built in and an Oscilloscope built it which is very very helpful in debugging circuits as we can see digital waveform in real time as like in real world, of course that DSO is not very fast or has limitations but it is better than noting, also it has buzzers and other more RGB led as I/O which makes it more interactive.

Also like the generic version, it has all the help built in for extra added items and also it has very good developer support.

Next version comes the logism IITD version, as we can see that it is the IIT Delhi version and the most notable feature of this version is the inbuilt IEEE floating point support, that's it there is nothing extra more in this version.

 Next comes the logisim evolution variant, this is the most helpful one for transforming a design or a simulation into a real world CPU, as it supports translating the design into VHDL and supports a lot of low cost FPGAs with cheap toolchain support and thus can help in transferring our design into real practical world and make it work on the FPGA.

It is almost like the original logisim but, has a lot more going on inside, it has complete help for translating to VHDL or writing backend VHDL and simulating it, it has support for a large number of example and cheap FPGA boards which can take our VHDL and reprogram the FPGA.

 

 

Next comes the cs3410 version, it is nothing new but the generic version in development, whose original development was halted by the author and is now no more supported, it is basically useless to use it as main software for project as it was in development stage and not in release stage, so we can skip it.

 

 

 

 

So, at last, if I would have to say that which version is the best, I would say it would be Logisim-ITA as it is written and maintained in current JAVA version and also it has some extra feature such as fitting the whole diagram in window easily and zoom and scaling and panning and also it has a DSO which can help a lot in difficult times, Other one variant if any one likes VHDL or has FPGA boards is the Logisim evolution, this version is the best for transferring the design from computer to real world but the only problem is you need a FPGA board compatible, also evolution has some issues with leading leagy logisim generic files, so Logisim-ITA is best.

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Technical Review : Logisim, an open source simulation software for Digital Electronics, Microprocessors & Computer Architecture, Organization

So, we all have done basic digital circuits on breadboard and now in this difficult time where we cannot go to our colleges for practical classes we need a simulation software that is small in size, consumes less resources and is free of cost. So, I was exploring Logisim ( a software which helps us to simulate digital circuits ) and here is a short technical review of it !

First of all Logisim is an open-source software that is it's code is open to see and modify for anyone and second it is only of 7 MB almost, so this makes it so tiny but the most useful as it can help simulate digital circuits on the fly and also it's simplicity and level of abstraction makes it very easy to simulate small model CPU's with almost all logic in it, means an entire CPU can be simulated within this software.

 

 

Next most important thing to be told is it can perform only digital circuit simulation and cannot perform analog simulations or even mixed(analog+digital) signal simulations, as we can see it is so small in size.

 

Upon downloading the software from its original source, we will get a .JAR file so we can see it is a JAVA executable and so we must have JAVA Runtime environment in our system, that is the ultimate requirement except that this can run on any operating system be it Linux, MAC OS or Windows.

 

Next, as we can see it is a very new software and we might think how we can learn it to be able to use it and run simulations, so for that it has a completely offline user manual which has almost all topics covered by the author of this software and reading this sequentially will almost teach how to use this software and reading the entire thing will not take much time.

 

So, If we start learning this software and try using it for doing Digital Electronics circuits we will understand how easy and simple it is in terms of simulation. It does not have analog simulation but has a system clock which provides clock signal for our circuits and also it hides all the digital logic stuff, and just presents us with the fundamental and universal gates and other inbuilt components like registers, flip flops and other 7 segment decoders. For I/O it has 7-SEG displays, LED lights and much more, also it has the capability of adding more I/O such as buzzers and other things via its JAR library feature.

Also upon exploration one will find the availability of  libraries which add a lot of features to this tiny software and also make it more capable, there are 74XX series IC library which has all the chips with the pin numbers, there is many other passive libraries which give us an upper hand on design and next comes may libraries which are based on JAVA and give us an upper hand on interaction with the components like buzzer, more I/O, PLA ROM and much more, but however they are limited and has bugs. I have collected all possible libraries and have stored them with their usable names, if you want you can find them on the internet too, but if you want in a bundle to try out all of them, then comment below.

It hides all the abstraction and just present us with the real world components as we see, even there is no need of caring for voltage sources or sinks or even current draws, one can say it as demerit but here where we just need to learn basic logic and simulate large scale simple CPUs here those small things which are complex and in analog domain don't matter much as we are only caring about digital logic and design and simulation.

For covering the analog level based and edge based things and most notably the clock, it has already given one which is extremely useful as for clock circuits we generally rely on 555 timer ICs and here in digital only simulator it is just impossible.

So, in short as a conclusion I would like to say that, Logisim is a great software for digital electronics domain and despite of its development halted by its original author back in 2011, it is still developed by everyone and maintained by everyone around the world and has full support on almost any topic if searched properly on the internet, all the shortcomings it has on the non-availability of analog simulation domain are covered by inbuilt or add-on libraries. Also if we see closely about it on the internet it has a lot of variants and infinite examples to learn from it and we can also see that students all over the world be it from United states or small country use it for learning digital electronics and we in INDIA should also adopt that, It is used by both computer science learners and electronics learners to learn digital electronics and microprocessors with ease. Last of all being it open-source helps us in making projects and submitting them as we can submit them without any extra licensing cost.

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Offtopic from Technology related post 004 : Indian Situation Report [Coronavirus Disease (COVID-19)] [part 4]

Indian Situation Report [Coronavirus Disease (COVID-19)]

Stock markets:

Impact of COVID-19 on National Stock Exchange of India NIFTY 50 (1 Jan 2020 to 19 May 2020). "The NIFTY 50 is NSE's benchmark broad based stock market index for the Indian equity market."

On 23 March 2020, stock markets in India post worst losses in history.[12] SENSEX fell 4000 points (13.15%) and NSE NIFTY fell 1150 points (12.98%).However, on 25 March, one day after a complete 21-day lock-down was announced by the Prime Minister, SENSEX posted its biggest gains in 11 years, adding a value of ₹4.7 lakh crore (US$66 billion) crore for investors. On 8 April, following positive indication from the Wall Street that the pandemic may have reached its peak in the US, the stock markets in India rose steeply once again. By 29 April, Nifty held the 9500 mark.

E-commerce:

In the third week of March, Amazon announced that it would stop sale of non-essential items in India so that it can focus on essential needs. Amazon has followed the same strategy in Italy and France.On 25 March, Walmart-owned Flipkart temporarily suspended some of its services on its e-commerce platform and will only be selling and distributing essentials. BigBasket and Grofers also run restricted services, facing disruptions in services due to the lockdown. Delhi Police began issuing delivery agents curfew passes to make it easier for them to keep the supply chain open. E-commerce companies also look for legal clarity related to what are "essentials".



There are concerns as to where will the government find the funds to fight coronavirus and keep the economy alive. Experts say the task force will have to look in to NPA norms, tax payments and income support to those in the unorganised sectors. A direct cash transfer scheme for the most vulnerable is also being considered, as has happened in other countries. The Press Information Bureau brought out a fact check that stories about a financial emergency being imposed in India are fake. A financial emergency has never been imposed in the history of India as yet.

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Offtopic from Technology related post 003 : Indian Situation Report [Coronavirus Disease (COVID-19)] [part 3]

Indian Situation Report [Coronavirus Disease (COVID-19)]

GDP :

On 27 March, Moody's Investors Service downgraded its estimate of India's GDP growth for 2020 from 5.3% to 2.5%. Fitch Ratings revised its estimate for India's growth to 2%. India Ratings & Research also downgraded the FY21 estimate to 3.6%.In April 2020, the World Bank and rating agencies downgraded India's growth for fiscal year 2021 with the lowest figures India has seen in three decades since India's economic liberalization in the 1990s.On 12 April 2020, a World Bank report focusing on South Asia said that India's economy is expected to grow 1.5% to 2.8% for FY21. The World Bank report said that the pandemic has "magnified pre-existing risks to India's economic outlook". In mid-April the International Monetary Fund projection for India for the FY21 of 1.9% GDP growth was still the highest among G-20 nations. Confederation of Indian Industry (CII) estimated that India's GDP for FY21 will be between 0.9% and 1.5%.

Energy:

Night lights and economic activity are connected. In Delhi, night light radiance fell 37.2% compared to 1–31 March 2019. This was the biggest fall for any metro in India. Bangalore fell 32% while Mumbai dropped by 29%.India's fuel demand in April 2020 as compared to the previous year fell nearly 46%. Consumption of fuel was the lowest since 2007. Cooking gas (LPG) sales rose ~12%. An International Energy Agency report in April estimated India's annual fuel consumption will decline 5.6% in 2020. Diesel demand will drop ~6%.

Agriculture:

A study during the first two weeks of May by the Public Health Foundation of India, Harvard T H Chan School of Public Health and the Centre for Sustainable Agriculture found that "10% of farmers could not harvest their crop in the past month and 60% of those who did harvest reported a yield loss" and that a majority of farmers are facing difficulty for the next season. Due to logistical problems following the lockdown tea estates were unable to harvest the first flush. The impact of this on the second flush is not known. The entire Darjeeling tea based tea industry will see significant fall in revenue.Tea exports could drop up to 8% as a result. During the lockdown, food wastage increased due to affected supply chains, affecting small farmers.

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Offtopic from Technology related post 002 : Indian Situation Report [Coronavirus Disease (COVID-19)] [part 2]

Indian Situation Report [Coronavirus Disease (COVID-19)]

24 MAY 2020: WHO SITUATION UPDATE STATED INDIA (24.05)131,868 CONFIRMED CASES3,867 TOTAL DEATHSSOUTH EAST ASIA REGION(23.05)182, 278 CONFIRMED CASES5, 556 TOTAL DEATHSWORLD(23.05)5,103,006 CONFIRMED CASES333,401 DEATHS.

The economic impact of the 2020 coronavirus pandemic in India has been largely disruptive. The World Bank and rating agencies had initially downgraded India's growth for fiscal year 2021 with the lowest figures India has seen in three decades since India's economic liberalization in the 1990s. How ever after the announcement of the economic package in mid-May, India's GDP estimates were downgraded even more to negative figures, signalling a deep recession. On 26 May, CRISIL announced that this will perhaps be India's worst recession since independence. State Bank of India research estimates a contraction of over 40% in the GDP in Q1 FY21.

Within a month, unemployment rose from 6.7% on 15 March to 26% on 19 April. During the lockdown, an estimated 14 crore (140 million) people lost employment. More than 45% of households across the nation have reported an income drop as compared to the previous year. The Indian economy was expected to lose over ₹32,000 crore (US$4.5 billion) every day during the first 21-days of complete lockdown, which was declared following the coronavirus outbreak. Under complete lockdown, less than a quarter of India's $2.8 trillion economic movement was functional. Up to 53% of businesses in the country were projected to be significantly affected .Supply chains have been put under stress with the lockdown restrictions in place; initially, there was a lack of clarity in streamlining what an "essential" is and what is not. Those in the informal sectors and daily wage groups are the most at risk. A large number of farmers around the country who grow perishables are also facing uncertainty. Various businesses such as hotels and airlines, are cutting salaries and laying off employees

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Offtopic from Technology related post : Current COVID-19 Situation

Current COVID-19 Situation : The coronavirus COVID-19 pandemic is the defining global health crisis of our time and the greatest challenge we have faced since World War Two. Since its emergence in Asia late last year, the virus has spread to every continent except Antarctica. Cases are rising daily in Africa the Americas, Europe AND ASIA.

Countries are racing to slow the spread of the virus by testing and treating patients, carrying out contact tracing, limiting travel, quarantining citizens, and cancelling large gatherings such as sporting events, concerts, and schools. The pandemic is moving like a wave—one that may yet crash on those least able to cope. But COVID-19 is much more than a health crisis. By stressing every one of the countries it touches, it has the potential to create devastating social, economic and political crises that will leave deep scars. As the UN’s lead agency on socio-economic impact and recovery, UNDP will provide the technical lead in the UN’s socio-economic recovery, supporting the role of the Resident Coordinators, with UN teams working as one across all aspects of the response. We are in uncharted territory. Many of our communities are now unrecognizable. Dozens of the world’s greatest cities are deserted as people stay indoors, either by choice or by government order. Across the world, shops, theatres, restaurants and bars are closing.

Every day, people are losing jobs and income, with no way of knowing when normality will return. Small island nations, heavily dependent on tourism, have empty hotels and deserted beaches. The International Labour Organization estimates that 195 million jobs could be lost.

The COVID-19 pandemic in India is part of the worldwide pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first case of COVID-19 in India, which originated from China, was reported on 30 January 2020. As of 30 May 2020, the Ministry of Health and Family Welfare have confirmed a total of 173,763 cases, 82,370 recoveries (including 1 migration) and 4,971 deaths in the country. India currently has the largest number of confirmed cases in Asia with number of cases breaching the 100,000 mark on 19 May 2020. India's case fatality rate is relatively lower at 3.09%, against the global 6.63% as of 20 May 2020. Six cities account for around half of all reported cases in the country – Mumbai, Delhi, Ahmedabad, Chennai, Pune and Kolkata. As of 24 May 2020, Lakshadweep is the only region which have not reported a case.

On 22 March 2020, India observed a 14-hour voluntary public curfew at the instance of the prime minister Narendra Modi. The government followed it up with lockdowns in 75 districts where COVID-19 cases had occurred as well as all major cities. Further, on 24 March, the Prime Minister ordered a nationwide lockdown for 21 days, affecting the entire 1.3 billion population of India. On 14 April, the prime minister extended the ongoing nationwide lockdown till 3 May. On 1 May, lockdown across the country was further extended by two more weeks till 17 May. On 17 May, NDMA further extended the nationwide lockdown till 31 May. Dr V Ravi, Head of Neuro virology, National Institute of Mental Health and Neurosciences, said that up to 50 percent people in India would be infected by COVID-19 by the year-end if further relaxations are introduced to lockdown rules after May 31.

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Random Photographs 005 by Subhankar [Opening a phone and taking external power supply to know how every small component works]

 Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

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Random Photographs 004 by Subhankar [Taking Closeup pictures of pixels of the display using a manual focus web cam]

  Photo by : Subhankar Karmakar

Theme : Technology - Taking Closeup pictures of pixels of the display using a manual focus web cam

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Random Photographs 003 by Subhankar [Opening a phone and taking external power supply to know how every small component works]

  Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

   

 

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Random Photographs 002 by Subhankar [Opening a phone and taking external power supply to know how every small component works]

  Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

 

 

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Random Photographs by Subhankar [Opening a phone and taking external power supply to know how every small component works]

 Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

                                       

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Compact Disks

In 1982 the fruits of a partnership between Sony and Philips were released to the music-loving public the compact disk or CD was unveiled as the first consumer digital audio format.

These 12 centimeter discs could store up to 74 minutes of perfect quality digital audio and as was famously demonstrated many times over, which're immune from liquid damage could withstand significant scratching and could be played without wearing them down for a theoretically infinite number of times.

                                                      

That's because unlike all previous sound, That's where the sound is encoded as an analog impression of the sound wave on plastic discs or Magnetic Tape the sound on a CD is encoded as a series of samples which function as a set of instructions on how to recreate the sound.

The compact disc was a big freaking deal in many ways. It represented a giant leap inconvenience for the consumer quality of the recorded sound and in raw data storage capacity that last bit wouldn't be too relevant to the Computing industry for some time, but it's solved the Central problem of digital sound needing  time for absurdly massive amount of raw Data,

                                                                                                                before we get too far into the specifics of the compact disc. It's time to dig a little deeper into how digital sound actually works for call . That an analog to digital converter is taken instantaneous samples of the analog signal at a specific sampling frequency. Then a digital to analog converter can recreate the original analog signal with only those samples. Well, a lot of people thought that this can't possibly work.

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