Different kinds of roms and their applications.

March 31, 2012

There are four types of ROM: regular ROM, PROM, EPROM and EAROM.

ROM stands for read only memory. A ROM can’t be changed, which means that once it has been manufcatured the contents of it can’t be changed.
The fact thaht ROMs are permanent gives them a security over programs stored in regular memory which can be changed by powerloss, viruses,
hackers and accidental misstakes. A typical application of a ROM might be an industrial machine that reapets the same sequence over and over
to manufcature auto parts. Another example might be the boot up software for a regular PC, which performs the same task each time the power is turned on.
ROMs however also have som disadvantages. One is that it takes a long time to manufacture a rom, which means that you might loose revenues due to cost delays. Abnother one is that the unit price of a ROM is quite high which means that you have to order at least something like thousand units, this fact makes the intial investment cost high. Once the ROM has been manfactured and in error has been discovered in the information store you can’t change the contents, this means making misstakes are very expensive.

To solve the problems of rom three other types of user programmable ROMs has been developed: PROM, EPROM and EAROM.
PROM stands for Programmable ROM. Information is program into a prom by burning of different electrical connection points. Depending of what’s is burned you code either ao one or a zero into the rom. PROMs are relatively cheap to manfucaturer which means that misstakes are not as expensive. PROMs are often used for testing phases where
you need to try out many different programs before finding the right one. When the right program has been found an eletrically compatbile ROM can take the place of PROM giving the final product a greater relability. However if you need to make frequent changes you have to discared one PROM each time which will be a vaste of money in the long run. Therefore there are ROMs which can be erased and reprogrammed by the user.

EPROM stands from electrically programmable ROM. You can erasure the contents of a an EPROM by submitting it to ultraviolet let for five to ten minutes. The circuits are however relatively expensive per unit and aren’t pin compatbile with PROMS and ROMS, this means that you have to change a design of the circuit board when you wish to make the final product which often uses ROMs. EPROMs loose their charge of many years pass by which means that if you have applications which will run for many years you should choose ROMs or PROMs instead.

Finally there are EAROM which stands for Electrically alterabkle ROM. These ROMS can be both written and read. However writing is very slow so it can be considered as a read often memory. EARoms is an expensive and complex technolog and is therefore most oftenly used for industrial and military applications.
To sum it up the kind of ROM you will use depends on the application type.

Circuit diagram of a 16K static ROM (83164).

Intel 2164 a 64kbit dynamic ROM, with an access time of 150ms.

Deletion of an Intel 2716 16K EPROM. The deletion is performed by directing UV light onto the window of the circuit.

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I found an interesting video from Ericson and MTS on installing 3G sites on the Russian tundra

March 28, 2012

I found a nice video from Ericsson on installing 3g sites on the Russian tundra. It’s quite amazing that Ericsson in cooperation with a large Russian operator called MTS was able to set up hundreds of 3g sites on the Russian tundra to give people in rural areas Internet and mobile broadband access. You can watch the video here.

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ShapeUp Club and BodyMonitor, two andriod apps to help you to stay fit!

March 25, 2012

I’ve found two android apps which help you stay fit. The first is called ShapeUp Club and the second is called Body Monitor.
Shape Up Club is a calorie counter which helps you keep track of how many calories you take in and consume everyday. The application has
a database of more than four hundred thousand food items, so you can find a lot of thing which you might eat in this database. You can enter
your intake and consumption of calories within the application. The consumption of calories is calculated by entering what type of workout you have done and for
how many minutes or hours you worked out. How many calories you consumed during that workout, It’s especially suitable for smartphones since you can find different kinds of food
by pointing and touching instead of entering data with the touch keyboard. It can also tack your weight, body fat and measurements. The application can
give you a summary of the number of calories you’ve consumed during the last 30 days. This summary contains an average amount of calories which you’ve consumed
during each week. The software can graph your measurements, your weight and body fat. The graphs are very informative and easy to read.

The startup screen of shapeub club

The startup screen of ShapeUp Club

Body monitor is an application to monitor your body fat, weights and measurements. One of the best features of this software is that it graphs your weight, body fat or measurements
during the last 30 days, You can check the graph to see if the trend i it’s going up or down. The software has a calendar view where you can enter
your weight, height, body fat and so on for each day. It let’s you track the fitness of several users so your entire family can use it! Graphs can be exported to
and SD card and weight and other fitness can also be exported to your SD card in a format that is readable by common spreadsheet applications such as Excel.*

Body Monitor Calender Screen

Body Monitor Calender Screen

Body Monitor Graph Screen

Body Monitor Graph Screen


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An interesting andriod based doro smartphone aimed at senior citizens

March 20, 2012

The phone is clamshell phone and it has both a touch screen and number pad with navigation  buttons. It runs a user interface especially adopted for senior citizens on top of andriod. Unfortunately users are not able to access andriod market but are limited to a special application market from Doro. Not being able to access andriod market kind of cripples the whole concept of an andriod phone because the numbers of apps users are able to install are very limited. Only apps approved by Doro to work on the phone can be installed. There is a web portal where you can change the settings of the phone in case a senior citizen needs help from a technically able person.

When I’ve worked with senior citizens I’ve noticed their need for products that are simple too use and meets their need for better ergonomics such as larger text and slower moving cursors. I think this product will be a hit among seniors.

Doro Phone Easy

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A lesson on the difference beetween static and dynamic ram

March 13, 2012

The static ram stores information as long as the power is turned on. This type of memory doesn’t need timing since it’s asynchronous.

Dynamic ram on the other needs to be recharged at regular intervals to maintain it’s information. The recharging is timed by an external timing crystal. This type typically needs to be refreshed
every few milliseconds. The refresh is done by reading the information and thereafter writing it back so that memory cell is kept up to date. The refresh is typically done several rows or columns at a time.

Dynamic ram is more cost effective to produce since it has a greater component density than static ram. On the other hand static ram is more reliable since it doesn’t need to refreshed at regular intervals.

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Installing NFS Carbon on Acer Aspire One 522.

March 6, 2012
NFS Carbon on Acer Aspire One 522

NFS Carbon on Acer Aspire One 522

Yesterday I installed Need For Speed Carbon on my netbook. First I converted the game CD into an ISO with an application for this purpose. Thereafter I copied the iso file to my hard drive. I used to daemon tools to install the game using the .iso file. Daemon tools is a software that fools the computer that an iso file is a regular CD/DVD drive. You can use this application to run iso files just as if you had the original CD.

After the setup I ran the game by mounting the .iso image using daemon tools and clicking the icon on the start menu. The game ran reasonably well but there was a small amount of lag when computer moved objects around. One of the reasons why game runs reasonably well on this netbook despite it’s dual core processor of only 1.0ghz is that is has an integrated radeon Radeon HD 6250

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Installing Ubuntu Linux 11.10 on Acer Aspire One 522

March 4, 2012

Installing Linux on this machine is a task not entirely without problems.Roughly one time out of three the installation software hangs, I have no idea why but one problem might be driver support. Once installed the Ubuntu runs reasonably well, but I’ve had some problems with the wlan adapter. Sometimes connections are dropped and sometimes you can’t connec to networks. The wlan problem seems too solved by running update for Ubuntu and let it update all of the drivers and other software.

The performance is not the best but it’s acceptable. Software loads a little bit slow and the multitasking is a bit slow if you have many applications running. When Ubuntu is installed it gives you the option if installing 3rd Party AMD drivers which are supposed to accelerate graphics processing. However once these drivers are installed you get a message saying that the hardware you have is unsupported and sometimes the computer hangs when you logon to the computer.

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The design faults of modern cellphones

February 28, 2012

One of the design faults of the modern smartphones is that they are becoming too large. An issue with this is that the phones are becoming too large to fit in a jeans pocket, If you once again start shrinking screens of smartphones they will fit regular pockets again. Another is that the screens are becoming too large to reach everywhere with a finger this makes it more difficult to navigate. The third is that mechanical buttons are being replaced by capacitive touch buttons. It’s easy to press these by mistake since it’s not clear where they end. Mechanical buttons can be used while wearing regular gloves while touch buttons can’t.

The race to build ever lighter phones has led to smartphones becoming more fragile because there’s not enough plastic to absorb shocks. Many modern phones lacks d-pads or trackballs which makes it easier to navigate between lines when you edit text they also some times allow for more precise navigation on the screen than moving your finger around. It’s not possible to use capacitive screen while wearing gloves and therefore it’s especially important to add a d-pad or trackball which can be used while wearing gloves. So to sum it up a practical smart phones has a screen of maximum 4inches, a sturdy chassis which has enough plastics to absorb shocks, has mechanical buttons and a d-pad or trackball for navigation while wearing gloves.

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Intel 8080 and the way the 40pins limits it’s IO performance.

February 23, 2012

Another lesson on microprocessors and the intel8080 especially. The Intel 8080 has 40pins which enables it communicate with the outside world. The processors is 16bit bits internally but it only has enough pins on the databuss to fetch 8bits at a time. The processor is able to process 16bit instructions by fetching two 8bit memory positions after each other through use of a technology called multiplexing. The problem is that the multiplexing technology is slow so at best the intel 8080 is only a little bit faster than an 8bit processor of similar specifications. The only way of speeding up the Intel 8080 and making it able to load 16bits at a time from memory would be to give it more pins to communicate with the outside world.

A nice video on microprocessors

February 18, 2012

I found a nice video from Intel on how microprocessors are manufactured. The video describes the manufacturing process of a microprocessor in laymen terms.
Click this link to see the video.

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