Silicon Laboratories SI5319, SI5369, SI5365, SI5366, SI5367, SI5374 Automatic/Manual Clock Selection

Si53xx-RM

6.3.2. Automatic Clock Selection (Si5322, Si5323, Si5365, Si5366)

The AUTOSEL input pin sets the input clock selection mode as shown in Table 24. 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 25 and Table 26). Digital hold is indicated by all CnB signals going high after a valid ICAL.

Table 24. Automatic/Manual Clock Selection

AUTOSEL	Clock Selection Mode
L	Manual (See Previous Section)
M	Automatic Non-revertive
H	Automatic Revertive

Table 25. Clock Active Indicators (AUTOSEL = M or H) (Si5322 and Si5323)

CS_CA	Active Clock
0	CKIN1
1	CKIN2

Table 26. 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 27 and Table 28. This priority is hardwired in the devices.

Table 27. Input Clock Priority for Auto Switching (Si5322, Si5323)

Priority	Input Clocks
1	CKIN1
2	CKIN2
3	Digital Hold

68 Rev. 0.5