Silicon Laboratories SI5375 - Manual (Page 55)

Si53xx-RM
Rev. 1.2 55
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.
The prioritization of clock inputs for automatic switching is shown in Table 18 and Table 19. This priority is
hardwired in the devices.
Table 15. Automatic/Manual Clock Selection
AUTOSEL Clock Selection Mode
L Manual (See Previous Section)
M Automatic Non-revertive
H Automatic Revertive
Table 16. Clock Active Indicators (AUTOSEL = M or H) (Si5322 and Si5323)
CS_CA Active Clock
0 CKIN1
1 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
Table 18. Input Clock Priority for Auto Switching (Si5322, Si5323)
Priority Input Clocks
1 CKIN1
2 CKIN2
3 Digital Hold