Do MCF51JM have schmitt-trigger inputs?

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Do MCF51JM have schmitt-trigger inputs?

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celsoken
Contributor V

It sounds like a stupid question but I could not find in Coldfire V1 documentation any reference to schmitt-trigger inputs. In fact the word schmitt is not found at all. I'd like to save some schmitt ports...

 

Thanks for any hints,

 

Celso

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TomE
Specialist II
My first port of call was the MCF51JM data sheet:

 

http://www.freescale.com/files/32bit/doc/data_sheet/MCF51JM128.pdf?fpsp=1

 

Check the Vih and Vil figures, and Table 10 also gives:

 

Table 10: "DC Characteristics".

 

        Input hysteresis; all digital inputs Vhys: 0.06 x Vdd

 

So now we know Freescale uses the keyword "Hysteresis", search for that and find within the first few pages:

 

1.3.1 Feature List

 

• Input/Output
  — 66 GPIOs
  — Eight keyboard interrupt pins with selectable polarity
  — Hysteresis and configurable pull-up device on all input pins; configurable slew rate and drive strength on all output pins

 

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celsoken
Contributor V

Thanks TomE,

 

I owe U some beers.

 

Cheers,

 

Celso

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