In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Peter Van der Zee wrote:

Hi Thomas and Guenther;

The internal switching times and the propagation delays inside the silicon are constant, and independent of the oscillator clock used. The transition time us mortals can measure are the ones on the output pins, and I understand that those have been purposely rate-limited; obviously to reduce noise. The transition time of an output is also heavily influenced by the amount of capacitance presented by the lines/load connected to it; it is amazing to see how much effect 5 pF can have.

Using a special 1 pF oscilloscope probe and no connections to an output pin (just the pin itself) shows a bit less than a 10 nano second transition. Adding the few pF of a "normal" scope probe will readily slow that to about 15 nSec. Poorer (lower frequency) probes will fare worse.

Cheers form Maui, Hawaii,

Peter (pjv)

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