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68HC11 clocks

Started by Jeff Fox April 5, 2004
In some literature about the 68HC11 I see a reference to an 8Mhz
crystal and a 2MHz eClock.  Instructions execute in a given number
of clock cycles, but which clock?

Best Wishes,
Jeff Fox
In article <4fbeeb5a.0404051203.5a5910b3@posting.google.com>, 
fox@ultratechnology.com says...
> In some literature about the 68HC11 I see a reference to an 8Mhz > crystal and a 2MHz eClock. Instructions execute in a given number > of clock cycles, but which clock? > > Best Wishes, > Jeff Fox >
Either, it just takes 4 more OSC clock ticks more than E clock ticks ;) But seriously..... Most of the documentation refers to E clock cycles.
Hi,
The external frequency clock (8MHz for example) is four times the internal
clock (2MHz). So, your instructions are executed with internal clock, 2MHz
(500ns / cycle).

Regards,

Yvan
http://www.ybdesign.fr




"Jeff Fox" <fox@ultratechnology.com> a &#2013265929;crit dans le message de news:
4fbeeb5a.0404051203.5a5910b3@posting.google.com...
> In some literature about the 68HC11 I see a reference to an 8Mhz > crystal and a 2MHz eClock. Instructions execute in a given number > of clock cycles, but which clock? > > Best Wishes, > Jeff Fox