aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorAaron Rossetto <aaron.rossetto@ni.com>2022-06-03 15:21:25 -0500
committerAaron Rossetto <aaron.rossetto@ni.com>2022-06-03 13:58:23 -0700
commite80495654f7fe989dc6be95b06cd373c93cb7495 (patch)
tree4452c93c6f13b2ec2bff3490dbd6d6f6ebbadcc0
parentuhd: Align numeric data types in digital filter classes (diff)
downloaduhd-e80495654f7fe989dc6be95b06cd373c93cb7495.tar.xz
uhd-e80495654f7fe989dc6be95b06cd373c93cb7495.zip
N320: Revert PLL lock time reduction
This commit reverts the changes made in commit 81a9cc1f8 to reduce the time for the LMK PLL to report lock status. The decision to revert the change comes after an investigation found that reducing the overall time to detect lock correlates with an increase in an error reported by the TDC ('[ERROR] TDC measurements show a wide range of values! Check your clock rates for incompatibilities. ... Uncaught exception in method set_clock_source: TDC measurement out of expected range!'). Despite the LMK PLL reporting lock status, our investigation revealed that it takes additional time for the PLL to align the daughterboards' clocks closely enough to pass the TDC measurement's range limit (i.e., no samples exceeding the measurement mean +/- 500 ps). Reverting the change increases the amount of time between achieving lock status and taking the TDC measurements, thus greatly reducing the likelihood of the reported error.
-rw-r--r--mpm/python/usrp_mpm/dboard_manager/lmk_rh.py4
1 files changed, 2 insertions, 2 deletions
diff --git a/mpm/python/usrp_mpm/dboard_manager/lmk_rh.py b/mpm/python/usrp_mpm/dboard_manager/lmk_rh.py
index d2745b631..c18e6ec92 100644
--- a/mpm/python/usrp_mpm/dboard_manager/lmk_rh.py
+++ b/mpm/python/usrp_mpm/dboard_manager/lmk_rh.py
@@ -216,8 +216,8 @@ class LMK04828Rh(LMK04828):
(0x159, (self.pll1_n_divider & 0x3F00) >> 8), # PLL1 N divider [13:8], default = d6
(0x15A, (self.pll1_n_divider & 0x00FF) >> 0), # PLL1 N divider [7:0], default = d0
(0x15B, 0xC7), # PLL1 PFD: negative slope for active filter / CP = 750 uA
- (0x15C, 0x0F), # PLL1 DLD Count [13:8]
- (0x15D, 0xA0), # PLL1 DLD Count [7:0]
+ (0x15C, 0x27), # PLL1 DLD Count [13:8]
+ (0x15D, 0x10), # PLL1 DLD Count [7:0]
(0x15E, 0x00), # PLL1 R/N delay, defaults = 0
(0x15F, 0x0B), # Status LD1 pin = PLL1 LD, push-pull output
(0x160, (self.pll2_r_divider & 0x0F00) >> 8), # PLL2 R divider [11:8];