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| author | Scott Wood <scottwood@freescale.com> | 2014-04-07 23:49:35 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2014-04-07 23:49:35 (GMT) |
| commit | 62b8c978ee6b8d135d9e7953221de58000dba986 (patch) | |
| tree | 683b04b2e627f6710c22c151b23c8cc9a165315e /Documentation/pps | |
| parent | 78fd82238d0e5716578c326404184a27ba67fd6e (diff) | |
| download | linux-fsl-qoriq-62b8c978ee6b8d135d9e7953221de58000dba986.tar.xz | |
Rewind v3.13-rc3+ (78fd82238d0e5716) to v3.12
Diffstat (limited to 'Documentation/pps')
| -rw-r--r-- | Documentation/pps/pps.txt | 15 |
1 files changed, 0 insertions, 15 deletions
diff --git a/Documentation/pps/pps.txt b/Documentation/pps/pps.txt index c03b1be..d35dcdd 100644 --- a/Documentation/pps/pps.txt +++ b/Documentation/pps/pps.txt @@ -66,21 +66,6 @@ In LinuxPPS the PPS sources are simply char devices usually mapped into files /dev/pps0, /dev/pps1, etc.. -PPS with USB to serial devices ------------------------------- - -It is possible to grab the PPS from an USB to serial device. However, -you should take into account the latencies and jitter introduced by -the USB stack. Users has reported clock instability around +-1ms when -synchronized with PPS through USB. This isn't suited for time server -synchronization. - -If your device doesn't report PPS, you can check that the feature is -supported by its driver. Most of the time, you only need to add a call -to usb_serial_handle_dcd_change after checking the DCD status (see -ch341 and pl2303 examples). - - Coding example -------------- |