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GPIOxn
XCLKOUT
t
w(GPI)
TMS320F28044
Digital Signal Processor
SPRS357B–AUGUST 2006–REVISED MAY 2007
6.9.3
Sampling Window Width for Input Signals
The following section summarizes the sampling window width for input signals for various input qualifier
configurations.
Sampling frequency denotes how often a signal is sampled with respect to SYSCLKOUT.
Sampling frequency = SYSCLKOUT/(2 * QUALPRD), if QUALPRD
≠
0
Sampling frequency = SYSCLKOUT, if QUALPRD = 0
Sampling period = SYSCLKOUT cycle x 2 x QUALPRD, if QUALPRD
≠
0
In the above equations, SYSCLKOUT cycle indicates the time period of SYSCLKOUT.
Sampling period = SYSCLKOUT cycle, if QUALPRD = 0
In a given sampling window, either 3 or 6 samples of the input signal are taken to determine the validity of
the signal. This is determined by the value written to GPxQSELn register.
Case 1:
Qualification using 3 samples
Sampling window width = (SYSCLKOUT cycle x 2 x QUALPRD) x 2, if QUALPRD
≠
0
Sampling window width = (SYSCLKOUT cycle) x 2, if QUALPRD = 0
Case 2:
Qualification using 6 samples
Sampling window width = (SYSCLKOUT cycle x 2 x QUALPRD) x 5, if QUALPRD
≠
0
Sampling window width = (SYSCLKOUT cycle) x 5, if QUALPRD = 0
Figure 6-9. General-Purpose Input Timing
NOTE
general-purpose
The
XINT2_ADCSOC signal as well.
pulse-width
requirement
for
input
is
applicable
for
the
84
Electrical Specifications
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