AC SWITCHING CHARACTERISTICS AND WAVEFORMS
The AC specifications provided in the AC characteris-
tics tables that follow consist of output delays, input
setup requirements, and input hold requirements.
Output delays are specified with minimum and maxi-
mum limits, measured as shown. The minimum delay
times are hold times provided to external circuitry.
AC specifications measurement is defined by the
figures that follow each timing table. All timings are
referenced to 1.5 V unless otherwise specified.
Input setup and hold times are specified as minimums,
defining the smallest acceptable sampling window.
Within the sampling window, a synchronous input sig-
nal must be stable for correct microcontroller operation.
Key to Switching Waveforms
WAVEFORMS
INPUTS
OUTPUTS
Must be Steady
Will be Steady
May Change from H to L
May Change from L to H
Will be Changing from H to L
Will be Changing from L to H
Don’t Care, Any Change Permitted
Does Not Apply
Changing, State Unknown
Center Line is High-Impedance "Off” State
AC SWITCHING TEST WAVEFORMS
VIH = VCC
VCC ÷ 2
VCC ÷ 2
Test Points
VIL = 0
Output
Input
Notes:
For AC testing, inputs are driven at 3 V for a logic 1 and 0 V for a logic 0.
Élan™SC400 and ÉlanSC410 Microcontrollers Data Sheet
91
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