Re: why is freq Internally divided in uPs?

From: Ben Bradley (ben_nospam_bradley_at_mindspring.com)
Date: 12/30/04 

Date: Thu, 30 Dec 2004 01:30:24 GMT

On 27 Dec 2004 23:04:20 -0800, "funkymunky"
<prehistorictoad2k@yahoo.com> wrote:

>Hi,
>
>Ive studied the Intel 8085 and the 8051 as part of my curriculum. Im
>curious to know why in both of these devices, the clock that is applied
>to the device is internally divided by 2? why is half to clock value
>not given instead?

   Having learned on a 6502, I often wondered that myself about other
microprocessors. In the 6502, the oscillator frequency IS the internal
clock (and it has the on-chip crystal oscillator circuit, just like
most other such chips). It usually does a memory fetch or write on
every clock cycle, so many instructions took only as many clock cycles
as they needed memory accesses. The minimum was two, so one-byte
instructions such as register-to-register transfers and no-op take two
cycles.

>Thanx in anticipation
>
>regards
>Mayank

-----
http://mindspring.com/~benbradley

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