Tool/software:
Hi All,
Attempting to update the DCLKX_Y_DIV register after the initial configuration results in the output clock being misaligned.
Our configuration has the PLL in dual loop mode, feeding a 3GHz device clock to the output clock dividers. Our initial configuration has these dividers set to 24 & 30 providing 100MHz & 125MHz with DDLY in powerdown. Ideally, our output clocks would be phase aligned to the input clock (ClkIn0/1). Upon modifying the DCLKX_Y_DIV register, we noticed the output clocks are not aligned with each other.
We attempted to perform a SYNC, but still noticed a large phase offset after modifying the DCLKX_Y_DIV register.
Our process to update the output clock is as follows:
- Update DCLKX_Y_DIV
- Update DCLKX_Y_DDLY
- DCLKX_Y_DDLY_PD = 0
- SYNC_DISX = 0
- Set SYNC_MODE = 1 & SYNC_1SHOT_EN = 1
- Toggle SYNC_POL, wait 100ms, Toggle SYNC_POL
- SYNC_DISX = 1
- DCLKX_Y_DDLY_PD = 1
- Update DCLKX_Y_FMT
Note, the DDLY and DIV for each modified clock is the same. for example: DCLK2 & DCLK7 have DIV = 15, DDLY = 15. We originally attempted only updating DCLKX_Y_DIV but ran into the same misalignment.
Can someone help us understand what we have misconfigured to get this result? Or are we simply missing a sync operation?
I've attached the register map of PLL initial configuration.
000080 000000 010018 01010A 010210 010340 010410 010500 010601 010711 010818 01090A 010A10 010B40 010C10 010D00 010E01 010F11 01101E 01110B 011210 011340 011410 011500 011601 011710 01181E 01190A 011A10 011B40 011C00 011D00 011E01 011F11 012018 01210A 012210 012340 012410 012500 012601 012711 012818 01290A 012A10 012B40 012C10 012D00 012E01 012F11 013018 01310A 013210 013340 013410 013500 013601 013711 013820 013900 013A0C 013B00 013C00 013D08 013E03 013F00 01400B 014100 014200 014310 014400 014500 01469A 01470A 014810 014950 014A00 014B11 014C00 014D00 014EC0 014F14 015030 015100 01520A 015300 015402 015500 015602 015700 015801 015900 015A02 015BD4 015C20 015D00 015E1E 015F23 016000 016101 0162AD 016300 016400 01650C 016958 016A20 016B00 016C00 016D00 016E1B 017310 017700 018200 018300 016600 016700 01681E 055500
