answersLogoWhite

0

In the 8085, the internal clock frequency is internally divided by two. Since the basic operating timing frequency is 3 MHz, a 6 MHz crystal is connected externally.

Now, it is because,

One reason to divide a clock by two is to obtain an even 50% duty cycle square wave. It may be that the 8085 internally uses both clock edges, and wouldn't function if one half of the cycle happened to be much shorter than the other.

In the days when the 8085 was new, those nice canned oscillators weren't common, and people often cobbled together clock circuits out of discrete Crystal, capacitors, and logic gates. Dividing by two ensures that you have equally spaced rising and falling edges.

As for 6.144MHz, you will find that it can be divided by an integer to get common baud rate values, at least up to 38400.

User Avatar

Wiki User

14y ago

What else can I help you with?

Related Questions

If the frequency of the crystal connected to 8085 is 6MHz calculate the time to fetch and executed NOP instruction?

At a crystal frequency of 6MHz, the 8085 microprocessor has a clock frequency of 3MHz, or a period of 333 nanoseconds. The NOP instruction requires four clock cycles, three to fetch and one to execute, so the NOP instruction with a crystal frequency of 6MHz would take 1.333 microseconds to fetch and execute. This does not include wait states, each of which would add 0.333 microseconds to the timing.


What microprocessor did the original Macintosh computer use?

Motorola 68000 running at an effective speed of about 6MHz


What is the most common repeater frequency offset in the 2 meter band?

.6mhz


How large a band of frequencies does each televion broadcasting channel get?

6MHz


Why the clock frequency of 8085 is 3.14 MHz?

you are freering to the internal clock speed and the external clock speed corect? ECLK or ECLKNOT are external clocks to the microprocessor. they do not run it. they are for the microprocessors supporting hardware. the internal frequency is what the processor actually uses. the ECLK is divided by two( a 6MHZ cycle take half as long a 3MHZ, right). the reason external (E) clocks run twice as fas as a processor is because there is not much data that can be processed in one cycle. it also allows the supporting architecture to access the data twice as it is processed. think about accessing a memory slot, it would use one ECLK cycle to locate the slot and one ECLK cycle to right the data to the processor. reading memory is a very simple task, but it still take two cycles. if the ECLK didnt run at twice the speed of the internal clock, the processor would be idle half of the time. actually there is a frequency devider circuit using 555 timer which devides the crystal frequency by 2......and the microprocessor components function proper at 3.14 Mhz.


What is a clock frequency of of 80286microprosser?

The original design of the 80286 had it running at 6MHz or 8MHz, depending on the chip. Later versions could run as 12.5MHz. Some vendors provided a 25MHz version.


Program in TI Basic for the 15 MHz Z80 instead of for the 6 MHz Z80?

The TI-83 Plus has a clock speed of 6MHz. The newer TI-83 Plus Silver Edition and the entire TI-84 Plus series have a 15MHz clock speed, but usually run at 6MHz for compatibility with the older 83+. Assembly programmers can switch between the two speeds with a simple command. Unfortunately, BASIC programmers can not. They can use an assembly program that will do it for them, though.


What is the speed of z-80?

All microprocessors' speed is controlled by a capacitor, which the circuit designer can set. Different capacitors give different clock speeds. Most Z80s, though, run between 6MHz (the TI-83 Plus uses this speed for low power consumption) to up to 24MHz.


What are some of the features of an SB5101 router?

The SB5101 is a cable modem manufactured by Motorola. It is optimised to make full use of 6MHz DOCSIS cable channels, as well as being 100 times faster than a 56K analog phone modem. It is compatible with all Windows, Macintosh and Unix computers.


Why AM is used in TV video signals transmission and not FM?

AM has a smaller sideband bandwidth than FM, since the baseband bandwidth of NTSC video is already about 4.5MHz, using AM vestigial sideband the resulting bandwidth is only just under 6MHz (without partially suppressing one sideband, the resulting bandwidth would have been about 9MHz). Had FM been used instead the resulting bandwidth might have been around 100MHz instead.


Digital signals can send much more of this than analog?

Analog signals can't be compressed as well as a digital signal can. To transmit an image on analog television, every pixel is included in the signal. A standard NTSC screen includes 525 lines of 720 pixels, for a total of 378,000 pixels per frame. That's a lot, but it fits into the 6MHz bandwidth of a television channel. Japanese HDTV takes 20 MHz of bandwidth to send pictures with over 675,000 pixels. That's over two times as much signal to send a high definition picture and higher quality sound, but no other data.


What is the maximum video resolution for composite video cables?

There are two answers for this question. The first deals with composite signals and the second deals with cable. So... Answer one. Composite signals carry color video as a single signal. The resolution is limited to 480 lines or 576 lines because they are the two standard definition line counts. The signals are below 6MHz and are analog. There is no composite signal that carries HD signals. Answer two The cable that carries composite signals is generally fairly poor quality but is sufficient for short links between a DVD and a television for example. Longer runs need a co-ax cable designed to run video signals. The cable is identified as a 75 Ohm cable, that being a characteristic of the cable required for standard video transmission. Although there are many different grades of co-ax cable, a reasonable quality cable is capable of running any composite signal and will also run digital video in standard and high definition as well. Most video signals use the same type of cable so strictly speaking, there is no such cable as "composite".