Can't seem to find the actual resistance value of the pull up/pull down settings for digital inputs. ItsyBitsy M4 Express. Need to know actual values to figure into my calculations,
Thanks!
M4 Express: Actual resistance value of pull up/down
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- xanatos
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- dastels
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Re: M4 Express: Actual resistance value of pull up/down
It's not as simple as a resistance to Vcc or Gnd. See section 32.6.3 on page 818 of the SAM D5x data sheet. You can find a copy at https://www.mouser.com/datasheet/2/268/ ... 130176.pdf.
If you need to know/control exactly what the pull up/down is, don't enable the internal pull up/down and use an external resistor.
Dave
If you need to know/control exactly what the pull up/down is, don't enable the internal pull up/down and use an external resistor.
Dave
- xanatos
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Re: M4 Express: Actual resistance value of pull up/down
Thanks Dave. Page 818 is all about "OSC32KCTRL – 32KHz Oscillators Controller" - but I'm guessing it'll be in here somewhere :) I just need to be sure the pullups are in excess of 100k effectively. If not, like you said, I'll need to use external pull-ups/downs.
Thanks!
Dave
Thanks!
Dave
- dastels
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Re: M4 Express: Actual resistance value of pull up/down
I must have a slightly different version locally. Section 32 starting on pg 883.
Dave
Dave
- xanatos
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Re: M4 Express: Actual resistance value of pull up/down
Thanks Dave, I did find the section... trying to make sense of it now :)
Dave
Dave
- westfw
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Re: M4 Express: Actual resistance value of pull up/down
Actual values are down in the "Electrical Characteristics" pages (54.9 in my copy):
"Somewhere between 20k and 60k" is probably not what you were hoping for!
"Somewhere between 20k and 60k" is probably not what you were hoping for!
- xanatos
- Posts: 110
- Joined: Thu Jun 18, 2009 3:09 pm
Re: M4 Express: Actual resistance value of pull up/down
LOL! Thanks for that. Yes - I'll definitely be using external pullups on the lines that I'm concerned with! :)
Dave
Dave
Please be positive and constructive with your questions and comments.