7.3.12.3 Procedure for Using SYNC
This procedure must be used to put the device in SYNC mode.
- Use the flowchart to determine the SYNC category.
- Make determinations for OSCin and using SYNC based on the category
- If Category 4, SYNC cannot be performed in this setup.
- If category 3, ensure that the maximum fOSC frequency for SYNC is not violated and there are hardware accommodations to use the SYNC pin.
- If the channel divide is used, determine the included channel divide value which will be 2 × SEG1 of the channel divide:
- If OUTA_MUX is not channel divider and OUTB_MUX is not channel divider or SysRef, then IncludedDivide = 1.
- Otherwise, IncludedDivide = 2 × SEG1. In the case that the channel divider is 2, then IncludedDivide=4.
- If not done already, divide the N divider and fractional values by the included channel divide to account for the included channel divide.
- Program the device with the VCO_PHASE_SYNC = 1. Note that this does not count as applying a SYNC to device (for category 2).
- Apply the SYNC, if required
- If category 2, VCO_PHASE_SYNC can be toggled from 0 to 1. Alternatively, a rising edge can be sent to the SYNC pin and the timing of this is not critical.
- If category 3, the SYNC pin must be used, and the timing must be away from the rising edge of the OSCin signal.