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Justme
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In addition to the DC conditions you already mentioned, it also depends on how much there is bus capacitance and at what speed you want to communicate to determine how much current (or power) you want to spend to communicate at higher speeds.

And there is both maximum and minimum pull-up resistance range, as it can't be too low so that all devices on bus can sink enough current to pull the bus voltage low enough for all devices to reliably see a logic low level, while it can't be too high before DC leakage currents start to affect the bus high voltage.

Basically the distance between devices does not affect the pull-up values, but longer distance adds capacitance which you must charge fast enough to communicate at the speed you want so if you assumed short distance has small capacitance then larger distance has larger capacitance and then you may need to change pull-ups or communicate at slower speed.

In addition to the DC conditions you already mentioned, it also depends on how much there is bus capacitance and at what speed you want to communicate to determine how much current (or power) you want to spend to communicate at higher speeds.

Basically the distance between devices does not affect the pull-up values, but longer distance adds capacitance which you must charge fast enough to communicate at the speed you want so if you assumed short distance has small capacitance then larger distance has larger capacitance and then you may need to change pull-ups or communicate at slower speed.

In addition to the DC conditions you already mentioned, it also depends on how much there is bus capacitance and at what speed you want to communicate to determine how much current (or power) you want to spend to communicate at higher speeds.

And there is both maximum and minimum pull-up resistance range, as it can't be too low so that all devices on bus can sink enough current to pull the bus voltage low enough for all devices to reliably see a logic low level, while it can't be too high before DC leakage currents start to affect the bus high voltage.

Basically the distance between devices does not affect the pull-up values, but longer distance adds capacitance which you must charge fast enough to communicate at the speed you want so if you assumed short distance has small capacitance then larger distance has larger capacitance and then you may need to change pull-ups or communicate at slower speed.

Source Link
Justme
  • 171.8k
  • 6
  • 135
  • 350

In addition to the DC conditions you already mentioned, it also depends on how much there is bus capacitance and at what speed you want to communicate to determine how much current (or power) you want to spend to communicate at higher speeds.

Basically the distance between devices does not affect the pull-up values, but longer distance adds capacitance which you must charge fast enough to communicate at the speed you want so if you assumed short distance has small capacitance then larger distance has larger capacitance and then you may need to change pull-ups or communicate at slower speed.