[ntp:questions] [ATOM (PPS) Refclock] Capture assert AND clear

f.hiesinger f.hiesinger at studium.fau.de
Tue Apr 21 07:41:49 UTC 2015


 Hi Folks,
 I'm sourcing a pps-signal via GPIO on a raspberry Pi(debian whezzy). 
 The pps0 is configured to capture "Assert" AND "Clear" (mode = 0x11f3). 
 The internal echo-mechanism is used, so reception of BOTH edges is 
 required. Up to here everything works fine.
 When ntp (incl. ATOM Driver 22) is starting, it instantly reconfigures* 
 the pps0-behavior to maintain either Assert OR Clear Edges. fudge -> 
 flag2 1 inverts the behavior. Any suggestions, how to prevent ntpd from 
 reconfiguring the pps-source?

 BR,Fran


 * in detail, this pps-modebits are removed at the start of ntpd:
  PPS_CAPTURECLEAR 0x02 (depends on flag2)
  PPS_OFFSETASSERT 0x10
  PPS_OFFSETCLEAR 0x20
  PPS_ECHOASSERT 0x40
  PPS_ECHOCLEAR 0x80




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