MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
977
Preliminary—Subject to Change Without Notice
DFL[0:3] — Digital Filter Length
The DFL field 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
Section 24.6.4.5, “External Trigger Event Detection
for more information
on the digital filter.
NOTE:
The DFL field must only be written when the MODEx of all CFIFOs are configured
to disabled.When the digital filter is bypassed by using the input control, the DFL
is not considered and the trigger input signal is not filtered.
24.5.2.5
EQADC CFIFO Push Registers (EQADC_CFPR)
The EQADC CFIFO Push Registers (EQADC_CFPR) provide a mechanism to fill the CFIFOs with
command messages from the CQueues. Refer to
Section 24.6.4, “EQADC Command FIFOs
for more
information on the CFIFOs and to
Section 24.6.2.3, “Message Format in EQADC
for a description on
command message formats.
Table 24-5. Minimum Required Time to Valid ETRIG
DFL[0:3]
Minimum Clock Count
Minimum Time (ns)
(system clock = 120 MHz)
0b0000
2
16.66
0b0001
3
25.00
0b0010
5
41.66
0b0011
9
75.00
0b0100
17
141.66
0b0101
33
275.00
0b0110
65
541.66
0b0111
129
1075.00
0b1000
257
2141.66
0b1001
513
4275.00
0b1010
1025
8541.66
0b1011
2049
17075.00
0b1100
4097
34141.00
0b1101
8193
68275.00
0b1110
16385
136541.66
0b1111
32769
273075.00
FilterPeriod
S
(
ystemClockPeriod
2
DFL
)
×
1 S
(
ystemClockPeriod
)
+
=