NXP Semiconductors MPC5566, Reference Manual

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Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 19-15
minimum number of system clocks that must be counted by the digital filter counter to recognize a logic
state change.
Address: Base + 0x000C Access: R/W
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R 0 0 0 0 0 0 0 0 0 0 0 0
DFL
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Figure 19-4. eQADC External Trigger Digital Filter Register (EQADC_ETDFR)
Table 19-5. EQADC_ETDFR Field Description Table
Field Description
0–27 Reserved.
28–31
DFL[0:3]
Digital filter length. Specifies the minimum number of system clocks that must be counted by the digital filter counter
to recognize a logic state change. The count specifies the sample period of the digital filter which is calculated
according to the following equation:
Minimum clock counts for which an ETRIG signal needs to be stable to be passed through the filter are shown in
Table 19-6 . Refer to Section 19.4.3.4, “External Trigger Event Detection ,” for more information on the digital filter.
Note: The DFL field must only be written when the MODE n of all CFIFOs are configured to disabled.
Table 19-6. Minimum Required Time to Valid ETRIG
DFL[0:3] Minimum Clock Count
Minimum Time (ns)
(System Clock = 120MHz)
0b0000 2 16.67
0b0001 3 25.00
0b0010 5 41.67
0b0011 9 75.00
0b0100 17 141.67
0b0101 33 275.00
0b0110 65 541.67
0b0111 129 1075.00
0b1000 257 2141.67
0b1001 513 4275.00
0b1010 1025 8541.67
FilterPeriod S
(
ystemClockPeriod 2
DFL
) ×
1 S
(
ystemClockPeriod
)
+ =