SI5325C-C-GM Datasheet, PDF (55/178 Pages) Silicon Laboratories – ANY-FREQUENCY PRECISION CLOCKS

Si53xx-RM
5.3.2. Automatic Clock Selection (Si5322, Si5323, Si5365, Si5366)
The AUTOSEL input pin sets the input clock selection mode as shown in Table 15. Automatic switching is either
revertive or non-revertive. Setting AUTOSEL to M or H, changes the CSn_CAm pins to output pins that indicate the
state of the automatic clock selection (See Table 16 and Table 17). Digital hold is indicated by all CnB signals going
high after a valid ICAL.
Table 15. Automatic/Manual Clock Selection
AUTOSEL
L
M
H
Clock Selection Mode
Manual (See Previous Section)
Automatic Non-revertive
Automatic Revertive
Table 16. Clock Active Indicators (AUTOSEL = M or H) (Si5322 and Si5323)
CS_CA
0
1
Active Clock
CKIN1
CKIN2
Table 17. Clock Active Indicators (AUTOSEL = M or H) (Si5365 and Si5367)
CA1
CA2
CS0_CA3 CS1_CA4 Active Clock
1
0
0
0
CKIN1
0
1
0
0
CKIN2
0
0
1
0
CKIN3
0
0
0
1
CKIN4
The prioritization of clock inputs for automatic switching is shown in Table 18 and Table 19. This priority is
hardwired in the devices.
Table 18. Input Clock Priority for Auto Switching (Si5322, Si5323)
Priority
1
2
3
Input Clocks
CKIN1
CKIN2
Digital Hold
Rev. 1.2
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