Devuan fork of gpsd
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  1. '\" t
  2. .\" Title: ppscheck
  3. .\" Author: [see the "AUTHOR" section]
  4. .\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
  5. .\" Date: 28 Jul 2016
  6. .\" Manual: GPSD Documentation
  7. .\" Source: The GPSD Project
  8. .\" Language: English
  9. .\"
  10. .TH "PPSCHECK" "8" "28 Jul 2016" "The GPSD Project" "GPSD Documentation"
  11. .\" -----------------------------------------------------------------
  12. .\" * Define some portability stuff
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  15. .\" http://bugs.debian.org/507673
  16. .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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  19. .el .ds Aq '
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  21. .\" * set default formatting
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  23. .\" disable hyphenation
  24. .nh
  25. .\" disable justification (adjust text to left margin only)
  26. .ad l
  27. .\" -----------------------------------------------------------------
  28. .\" * MAIN CONTENT STARTS HERE *
  29. .\" -----------------------------------------------------------------
  30. .SH "NAME"
  31. ppscheck \- tool to check a serial port for PPS
  32. .SH "SYNOPSIS"
  33. .HP \w'\fBppscheck\fR\ 'u
  34. \fBppscheck\fR [\-h] [\-V] \fIdevice\fR
  35. .SH "DESCRIPTION"
  36. .PP
  37. ppscheck watches a specified serial port for transitions that might be PPS\&. It looks for changes in handshake lines CD, RI, and CTS by running ioctl(\&.\&.\&.\&., TIOCMIWAIT, \&.\&.\&.) in a loop\&. When it sees a state change it emits a timestamped line of output dumping the state of the handshake signals\&. It\*(Aqs useful for checking whether a device is emitting PPS\&.
  38. .PP
  39. To check the first serial port do this:
  40. .sp
  41. .if n \{\
  42. .RS 4
  43. .\}
  44. .nf
  45. ppscheck /dev/ttyS0
  46. .fi
  47. .if n \{\
  48. .RE
  49. .\}
  50. .PP
  51. ppscheck is not intended for routine use, but rather for diagnostic purposes\&. Once you have verified a particular device can output PPS signals you will never need to use it again on that device\&.
  52. .PP
  53. The program accepts the following options:
  54. .PP
  55. \-h
  56. .RS 4
  57. Display help message and terminate\&.
  58. .RE
  59. .PP
  60. \-V
  61. .RS 4
  62. Dump version and exit\&.
  63. .RE
  64. .PP
  65. The "device" argument should be the pathname of a device\&. It will be the device monitored\&.
  66. .PP
  67. Each output line is the second and nanosecond parts of a timestamp followed by the names of the handshake signals then asserted\&. Off transitions may generate lines with no signals aserted\&.
  68. .PP
  69. If you don\*(Aqt see output within a second, use gpsmon or some other equivalent tool to check that your device has a satellite lock and is getting 3D fixes before giving up on the possibility of PPS\&.
  70. .PP
  71. Check your cable\&. Cheap DB9 to DB9 cables such as those issued with UPSes often carry TXD/RXD/GND only, omitting handshake lines such as DCD\&. Suspect this especially if the cable jacket looks too skinny to hold more than three leads!
  72. .PP
  73. Most GPS that have built in USB do not support PPS\&. When in doubt, contact the vendor for confirmation that your device does supply PPS\&.
  74. .SH "RETURN VALUES"
  75. .PP
  76. 1 if the device counld not be opened\&. 0 otherwise
  77. .SH "SEE ALSO"
  78. .PP
  79. \fBgpsd\fR(8)\&.
  80. .SH "AUTHOR"
  81. .PP
  82. Eric S\&. Raymond
  83. <esr@thyrsus\&.com>\&.