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
68HC11 clocks
Started by ●April 5, 2004
Reply by ●April 5, 20042004-04-05
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.
Reply by ●April 6, 20042004-04-06
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 �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