68HC11 operative frequencies

gz — Wed, 22 Aug 2012 16:07:11 GMT

Happy to introduce myself with this simple question

As far as this 68hc11 brief profile says

The 68HC11E family MCUs all combine the M68HC11 CPU with high-performance, on-chip peripherals. The E series is comprised of many devices with various configurations of RAM, ROM or EPROM, and EEPROM. Several low-voltage devices are also available. With the exception of a few minor differences, the operation of all E-series MCUs is identical. A fully static design and high-density complementary metal-oxide semiconductor (HCMOS) fabrication process allow E-series devices to operate at frequencies from 3 MHz to dc.

[taken from

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=68HC11E1&nodeId=01624684498635

]

My question is the following:

given a designed board with external crystal running @ 8Mhz and MC68HC11E1CFNE2 working with Eclock @ E 2Mhz,

whenever I have to switch MCU on the socket for this board with a different MC68HC11E1CFNE3 (note the very last number),

is it guaranteed that external crystal running @ 8Mhz does good for a Eclock @ E 2Mhz and so there is not any impact on software application?

Thanks!

Re: 68HC11 operative frequencies

kef — Wed, 22 Aug 2012 17:15:07 GMT

Very last number specifies top bus clock in MHz. Since relation between bus and oscillator clock is fixed 1 to 4, 8MHz crystal will work with '3' and '2' equally well.

Re: 68HC11 operative frequencies

gz — Wed, 22 Aug 2012 19:34:31 GMT

Well, that's what I was expecting. Pretty good for me.

Thanks a lot kef ! Very quick indeed !

topic 68HC11 operative frequencies in 8-bit Microcontrollers

68HC11 operative frequencies

Re: 68HC11 operative frequencies

Re: 68HC11 operative frequencies