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Archive for July, 2009
images of nokia mobiles + latest nokia mobiles
Jul 7th
images of nokia mobiles + latest nokia mobiles
open-source hardware and software project – Simple DIY microcontroller based video game console
Jul 7th
This open-source hardware and software project shows just how much can be done with modern microcontrollers. It implements a fully functioning, NES-class programmable video game system in just a couple chips, a few resistors, and some other miscellaneous components.
This is a neat project that actually looks fairly powerful! Using only an ATmega644 microcontroller and an AD725 RGB-to-NTSC converter for major components, the Uzebox game console is a build-and-program-yourself project that is pretty simple, but also very impressive in the resulting product.
Hardware-wise, the console offers 4K of RAM and 64K of program space, with four channels of wavetable sound. Control inputs are setup for NES pads, but you could choose any similar input scheme since those old pads were just switches and not the complicated serial/analog stuff on modern commercial consoles.
The software is interrupt-driven, which prevents the programmer from having to count cycles, so its not quite as challenging to program as an Atari 2600, but should still be fun. You can access up to 256 colors thanks to the resistor-ladder DAC setup while the AD725 handles the heavy lifting to convert the signal to a standard TV-compatible NTSC signal.
Overall, it looks like you write some code that results in a very NES-class game. For example, look at the video of Tetris running on the Uzebox below and youll see that its definitely capable of NES-class games
FPGA board emulates classic platforms – play many games and platforms
Jul 7th
This cool projects aims to take the various FPGA-based arcade platforms and run them on a common piece of hardware, thus letting you play many games and platforms without having tons of equipment sitting around.
Ive written here about various FPGA arcade and emulator projects, such as the Minimig Amiga 500 project. All of these projects are using a hardware programming language like VHDL or Verilog to implement the circuitry of classic arcade and computer platforms on a regular, (relatively) cheap field programmable gate array (FPGA).
There is one project, though, which is attempting to create a single hardware platform that you can buy which will run many of these independent projects. Currently, the board is still in the design and debug phase, with only a few developers having them, but eventually, the FPGA Replay board will be offered as a pre-assembled unit which you can download the various games onto, or work on your own pet projects.
Currently, the games supported by the FPGA Replay include:
- Scramble
- Frogger
- Asteroids Deluxe
- Pac Man
- LadyBug
- Space Invaders
- Galaxian
Ill be keeping an eye on the progress of the FPGA Replay as I think this would be really fun to play around with, if only for the games. But, it could also be a challenging project to take one of my favorite games (like Robotron or Joust) and try to create the VHDL code to actually run it. I suppose thats something to add to my ever-growing list of “long term to-do” projects 
Microprocessor Memory RAM or ROM
Jul 7th
Microprocessor Memory
The previous section talked about the address and data buses, as well as the RD and WR lines. These buses and lines connect either to RAM or ROM — generally both. In our sample microprocessor, we have an address bus 8 bits wide and a data bus 8 bits wide. That means that the microprocessor can address (28) 256 bytes of memory, and it can read or write 8 bits of the memory at a time. Lets assume that this simple microprocessor has 128 bytes of ROM starting at address 0 and 128 bytes of RAM starting at address 128.
Photo courtesy ROM chip
ROM stands for read-only memory. A ROM chip is programmed with a permanent collection of pre-set bytes. The address bus tells the ROM chip which byte to get and place on the data bus. When the RD line changes state, the ROM chip presents the selected byte onto the data bus.
Photo courtesy
RAM chip
RAM stands for random-access memory. RAM contains bytes of information, and the microprocessor can read or write to those bytes depending on whether the RD or WR line is signaled. One problem with todays RAM chips is that they forget everything once the power goes off. That is why the computer needs ROM.
By the way, nearly all computers contain some amount of ROM (it is possible to create a simple computer that contains no RAM — many microcontrollers do this by placing a handful of RAM bytes on the processor chip itself — but generally impossible to create one that contains no ROM). On a PC, the ROM is called the BIOS (Basic Input/Output System). When the microprocessor starts, it begins executing instructions it finds in the BIOS. The BIOS instructions do things like test the hardware in the machine, and then it goes to the hard disk to fetch the boot sector (see How Hard Disks Work for details). This boot sector is another small program, and the BIOS stores it in RAM after reading it off the disk. The microprocessor then begins executing the boot sectors instructions from RAM. The boot sector program will tell the microprocessor to fetch something else from the hard disk into RAM, which the microprocessor then executes, and so on. This is how the microprocessor loads and executes the entire operating system.
Microprocessor Logic – how a microprocessor works
Jul 7th
Microprocessor Logic
 Photo courtesy Intel Corporation Intel Pentium 4 processor |
A microprocessor executes a collection of machine instructions that tell the processor what to do. Based on the instructions, a microprocessor does three basic things:
- Using its ALU (Arithmetic/Logic Unit), a microprocessor can perform mathematical operations like addition, subtraction, multiplication and division. Modern microprocessors contain complete floating point processors that can perform extremely sophisticated operations on large floating point numbers.
- A microprocessor can move data from one memory location to another.
- A microprocessor can make decisions and jump to a new set of instructions based on those decisions.
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This is about as simple as a microprocessor gets. This microprocessor has:
- An address bus (that may be 8, 16 or 32 bits wide) that sends an address to memory
- A data bus (that may be 8, 16 or 32 bits wide) that can send data to memory or receive data from memory
- An RD (read) and WR (write) line to tell the memory whether it wants to set or get the addressed location
- A clock line that lets a clock pulse sequence the processor
- A reset line that resets the program counter to zero (or whatever) and restarts execution
Here are the components of this simple microprocessor:
- Registers A, B and C are simply latches made out of flip-flops. (See the section on “edge-triggered latches” in How Boolean Logic Works for details.)
- The address latch is just like registers A, B and C.
- The program counter is a latch with the extra ability to increment by 1 when told to do so, and also to reset to zero when told to do so.
- The ALU could be as simple as an 8-bit adder (see the section on adders in How Boolean Logic Works for details), or it might be able to add, subtract, multiply and divide 8-bit values. Lets assume the latter here.
- The test register is a special latch that can hold values from comparisons performed in the ALU. An ALU can normally compare two numbers and determine if they are equal, if one is greater than the other, etc. The test register can also normally hold a carry bit from the last stage of the adder. It stores these values in flip-flops and then the instruction decoder can use the values to make decisions.
- There are six boxes marked “3-State” in the diagram. These are tri-state buffers. A tri-state buffer can pass a 1, a 0 or it can essentially disconnect its output (imagine a switch that totally disconnects the output line from the wire that the output is heading toward). A tri-state buffer allows multiple outputs to connect to a wire, but only one of them to actually drive a 1 or a 0 onto the line.
- The instruction register and instruction decoder are responsible for controlling all of the other components.
- Tell the A register to latch the value currently on the data bus
- Tell the B register to latch the value currently on the data bus
- Tell the C register to latch the value currently output by the ALU
- Tell the program counter register to latch the value currently on the data bus
- Tell the address register to latch the value currently on the data bus
- Tell the instruction register to latch the value currently on the data bus
- Tell the program counter to increment
- Tell the program counter to reset to zero
- Activate any of the six tri-state buffers (six separate lines)
- Tell the ALU what operation to perform
- Tell the test register to latch the ALUs test bits
- Activate the RD line
- Activate the WR line
Microprocessor Progression Intel complete 8-bit computer on one chip
Jul 7th
Microprocessor Progression: Intel
The Intel 8080 was the first microprocessor in a home computer. See
The first microprocessor to make it into a
home computer was the Intel 8080, a
complete 8-bit computer on one chip, introduced in 1974. The first
microprocessor to make a real splash in the market was the Intel 8088,
introduced in 1979 and incorporated into the IBM PC (which first appeared around
1982). If you are familiar with the PC market and its history, you know that the
PC market moved from the 8088 to the 80286 to the 80386 to the 80486 to the
Pentium to the Pentium II to the Pentium III to the Pentium 4. All of these
microprocessors are made by Intel and all of them are improvements on the basic
design of the 8088. The Pentium 4 can execute any piece of code that ran on the
original 8088, but it does it about 5,000 times faster!
The following table helps you to understand the differences between the
different processors that Intel has introduced over the years.
The date is the year that the processor was first
introduced. Many processors are re-introduced at higher clock speeds for many
years after the original release date.
Transistors is the number of transistors on the chip. You
can see that the number of transistors on a single chip has risen steadily over
the years.
Microns is the width, in microns, of the smallest wire on
the chip. For comparison, a human hair is 100 microns thick. As the feature size
on the chip goes down, the number of transistors rises.
Clock speed is the maximum rate that the chip can be
clocked at. Clock speed will make more sense in the next section.
Data Width is the width of the ALU. An 8-bit ALU can
add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate
32-bit numbers. An 8-bit ALU would have to execute four instructions to add two
32-bit numbers, while a 32-bit ALU can do it in one instruction. In many cases,
the external data bus is the same width as the ALU, but not always. The 8088 had
a 16-bit ALU and an 8-bit bus, while the modern Pentiums fetch data 64 bits at a
time for their 32-bit ALUs.
MIPS stands for “millions of instructions per second” and
is a rough measure of the performance of a CPU. Modern CPUs can do so many
different things that MIPS ratings lose a lot of their meaning, but you can get
a general sense of the relative power of the CPUs from this column.
From this table you can see that, in general, there is a relationship between
clock speed and MIPS. The maximum clock speed is a function of the manufacturing
process and delays within the chip. There is also a relationship between the
number of transistors and MIPS. For example, the 8088 clocked at 5 MHz but only
executed at 0.33 MIPS (about one instruction per 15 clock cycles). Modern
processors can often execute at a rate of two instructions per clock cycle. That
improvement is directly related to the number of transistors on the chip and
will make more sense in the next section
How Microprocessors Work
Jul 7th
The computer you are using to read this page uses a microprocessor to do its work. The microprocessor is the heart of any normal computer, whether it is a desktop machine, a server or a laptop. The microprocessor you are using might be a Pentium, a K6, a PowerPC, a Sparc or any of the many other brands and types of microprocessors, but they all do approximately the same thing in approximately the same way.
2008 HowStuffWorks
Microprocessors are at the heart of all computers
A microprocessor — also known as a CPU or central processing unit — is a complete computation engine that is fabricated on a single chip. The first microprocessor was the Intel 4004, introduced in 1971. The 4004 was not very powerful — all it could do was add and subtract, and it could only do that 4 bits at a time. But it was amazing that everything was on one chip. Prior to the 4004, engineers built computers either from collections of chips or from discrete components (transistors wired one at a time). The 4004 powered one of the first portable electronic calculators
If you have ever wondered what the microprocessor in your computer is doing, or if you have ever wondered about the differences between types of microprocessors, then read on. In this article, you will learn how fairly simple digital logic techniques allow a computer to do its job, whether its playing a game or spell checking a document
download Google Chrome For Mac free setup
Jul 7th
Manu-J has compiled and run the Google Chrome from Chrome Developers SVN repository. I have not run it nor have compiled it on my mac but after reading the report, looks like it is something I want to try. I am currently running Google Chrome 2.0 Beta on windows.
It seems to be faster on MACs (much faster than firefox) than Windows and most parts already work for basic web browsing.
If you want to try and do not want to goto troubles of compiling the app, you can download the compiled version from Manu-J. But make sure that you have an Intel Mac running Mac OS X 10.5 (“Leopard”). Another reminder, this is an unofficial Chrome release.
Good work Manu-j
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High-Definition VoIP (HD VoIP) Say Good Bye To “What Did You Say”
Jul 7th
Jeff Pulver was interviewed by Alan Reiter and both got into a discussion about hD VoIP, and I found it very interesting even though if was brief for my liking. I too share their passion and want to say good bye to “what did you say”, that I keep on repeating during many phone calls.
But Most interesting was a almost hidden announcement;
“Interested in HD VoIP? Register TODAY for the HD Communications Summit taking place in New York City on May 21st.”
Too bad I will be somewhere over in Europe celebrating my Grand Pas Birthday, during that time. But I suggest if you are or going to be around New York, on May 21, register for the HD Communications Summit!
Hope Jeff witll write about the summit so us folks who missed will know what happened!
