SLVSJ99A July 2025 – June 2026 TPLD2001-Q1
PRODUCTION DATA
When configured as a Frequency detector (FDET), this macro-cell indicates whether the input signal is faster or slower than the period specified by DATA. The initial output value of this macro-cell after device startup can also be configured to Bypass Initial, Initial Low, or Initial High. The edge on which the Frequency detector is reset is determined by the Edge select parameter and can be configured as:
Rising: rising edges of IN trigger and reset the frequency detector.
Falling: falling edges of IN trigger and reset the frequency detector.
Both: rising edges of IN triggers the frequency detector to begin counting and falling edges of IN reset the frequency detector.
Upon receiving a trigger, an additional 2 clock cycles is used to synchronize IN and the counter with CLK, then the counter begins decrementing from DATA on the following rising edge of CLK. For proper operation of the FDET macro-cell, TI recommends using a minimum DATA of 3.
If the internal counter reaches 0, the FDET macro-cell outputs a Low signal, indicating the input frequency is slower than DATA. Otherwise, if the counter is interrupted with a reset before reaching 0, the FDET macro-cell outputs a High signal, indicating a faster signal on IN.
Figure 8-19 shows an example of how the FDET macro-cell operates with respect to the Edge select parameter.