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1What: /sys/class/timecard/
2Date: September 2021
3Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
4Description: This directory contains files and directories
5 providing a standardized interface to the ancillary
6 features of the OpenCompute timecard.
7
8What: /sys/class/timecard/ocpN/
9Date: September 2021
10Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
11Description: This directory contains the attributes of the Nth timecard
12 registered.
13
14What: /sys/class/timecard/ocpN/available_clock_sources
15Date: September 2021
16Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
17Description: (RO) The list of available time sources that the PHC
18 uses for clock adjustments.
19
20 ==== =================================================
21 NONE no adjustments
22 PPS adjustments come from the PPS1 selector (default)
23 TOD adjustments from the GNSS/TOD module
24 IRIG adjustments from external IRIG-B signal
25 DCF adjustments from external DCF signal
26 ==== =================================================
27
28What: /sys/class/timecard/ocpN/available_sma_inputs
29Date: September 2021
30Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
31Description: (RO) Set of available destinations (sinks) for a SMA
32 input signal.
33
34 ===== ================================================
35 10Mhz signal is used as the 10Mhz reference clock
36 PPS1 signal is sent to the PPS1 selector
37 PPS2 signal is sent to the PPS2 selector
38 TS1 signal is sent to timestamper 1
39 TS2 signal is sent to timestamper 2
40 TS3 signal is sent to timestamper 3
41 TS4 signal is sent to timestamper 4
42 IRIG signal is sent to the IRIG-B module
43 DCF signal is sent to the DCF module
44 FREQ1 signal is sent to frequency counter 1
45 FREQ2 signal is sent to frequency counter 2
46 FREQ3 signal is sent to frequency counter 3
47 FREQ4 signal is sent to frequency counter 4
48 None signal input is disabled
49 ===== ================================================
50
51What: /sys/class/timecard/ocpN/available_sma_outputs
52Date: May 2021
53Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
54Description: (RO) Set of available sources for a SMA output signal.
55
56 ===== ================================================
57 10Mhz output is from the 10Mhz reference clock
58 PHC output PPS is from the PHC clock
59 MAC output PPS is from the Miniature Atomic Clock
60 GNSS1 output PPS is from the first GNSS module
61 GNSS2 output PPS is from the second GNSS module
62 IRIG output is from the PHC, in IRIG-B format
63 DCF output is from the PHC, in DCF format
64 GEN1 output is from frequency generator 1
65 GEN2 output is from frequency generator 2
66 GEN3 output is from frequency generator 3
67 GEN4 output is from frequency generator 4
68 GND output is GND
69 VCC output is VCC
70 ===== ================================================
71
72What: /sys/class/timecard/ocpN/clock_source
73Date: September 2021
74Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
75Description: (RW) Contains the current synchronization source used by
76 the PHC. May be changed by writing one of the listed
77 values from the available_clock_sources attribute set.
78
79What: /sys/class/timecard/ocpN/clock_status_drift
80Date: March 2022
81Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
82Description: (RO) Contains the current drift value used by the firmware
83 for internal disciplining of the atomic clock.
84
85What: /sys/class/timecard/ocpN/clock_status_offset
86Date: March 2022
87Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
88Description: (RO) Contains the current offset value used by the firmware
89 for internal disciplining of the atomic clock.
90
91What: /sys/class/timecard/ocpN/freqX
92Date: March 2022
93Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
94Description: (RO) Optional directory containing the sysfs nodes for
95 frequency counter <X>.
96
97What: /sys/class/timecard/ocpN/freqX/frequency
98Date: March 2022
99Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
100Description: (RO) Contains the measured frequency over the specified
101 measurement period.
102
103What: /sys/class/timecard/ocpN/freqX/seconds
104Date: March 2022
105Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
106Description: (RW) Specifies the number of seconds from 0-255 that the
107 frequency should be measured over. Write 0 to disable.
108
109What: /sys/class/timecard/ocpN/genX
110Date: March 2022
111Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
112Description: (RO) Optional directory containing the sysfs nodes for
113 frequency generator <X>.
114
115What: /sys/class/timecard/ocpN/genX/duty
116Date: March 2022
117Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
118Description: (RO) Specifies the signal duty cycle as a percentage from 1-99.
119
120What: /sys/class/timecard/ocpN/genX/period
121Date: March 2022
122Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
123Description: (RO) Specifies the signal period in nanoseconds.
124
125What: /sys/class/timecard/ocpN/genX/phase
126Date: March 2022
127Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
128Description: (RO) Specifies the signal phase offset in nanoseconds.
129
130What: /sys/class/timecard/ocpN/genX/polarity
131Date: March 2022
132Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
133Description: (RO) Specifies the signal polarity, either 1 or 0.
134
135What: /sys/class/timecard/ocpN/genX/running
136Date: March 2022
137Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
138Description: (RO) Either 0 or 1, showing if the signal generator is running.
139
140What: /sys/class/timecard/ocpN/genX/start
141Date: March 2022
142Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
143Description: (RO) Shows the time in <sec>.<nsec> that the signal generator
144 started running.
145
146What: /sys/class/timecard/ocpN/genX/signal
147Date: March 2022
148Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
149Description: (RW) Used to start the signal generator, and summarize
150 the current status.
151
152 The signal generator may be started by writing the signal
153 period, followed by the optional signal values. If the
154 optional values are not provided, they default to the current
155 settings, which may be obtained from the other sysfs nodes.
156
157 period [duty [phase [polarity]]]
158
159 echo 500000000 > signal # 1/2 second period
160 echo 1000000 40 100 > signal
161 echo 0 > signal # turn off generator
162
163 Period and phase are specified in nanoseconds. Duty cycle is
164 a percentage from 1-99. Polarity is 1 or 0.
165
166 Reading this node will return:
167
168 period duty phase polarity start_time
169
170What: /sys/class/timecard/ocpN/gnss_sync
171Date: September 2021
172Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
173Description: (RO) Indicates whether a valid GNSS signal is received,
174 or when the signal was lost.
175
176What: /sys/class/timecard/ocpN/i2c
177Date: September 2021
178Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
179Description: This optional attribute links to the associated i2c device.
180
181What: /sys/class/timecard/ocpN/irig_b_mode
182Date: September 2021
183Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
184Description: (RW) An integer from 0-7 indicating the timecode format
185 of the IRIG-B output signal: B00<n>
186
187What: /sys/class/timecard/ocpN/pps
188Date: September 2021
189Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
190Description: This optional attribute links to the associated PPS device.
191
192What: /sys/class/timecard/ocpN/ptp
193Date: September 2021
194Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
195Description: This attribute links to the associated PTP device.
196
197What: /sys/class/timecard/ocpN/serialnum
198Date: September 2021
199Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
200Description: (RO) Provides the serial number of the timecard.
201
202What: /sys/class/timecard/ocpN/sma1
203What: /sys/class/timecard/ocpN/sma2
204What: /sys/class/timecard/ocpN/sma3
205What: /sys/class/timecard/ocpN/sma4
206Date: September 2021
207Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
208Description: (RW) These attributes specify the direction of the signal
209 on the associated SMA connectors, and also the signal sink
210 or source.
211
212 The display format of the attribute is a space separated
213 list of signals, prefixed by the input/output direction.
214
215 The signal direction may be changed (if supported) by
216 prefixing the signal list with either "in:" or "out:".
217 If neither prefix is present, then the direction is unchanged.
218
219 The output signal may be changed by writing one of the listed
220 values from the available_sma_outputs attribute set.
221
222 The input destinations may be changed by writing multiple
223 values from the available_sma_inputs attribute set,
224 separated by spaces. If there are duplicated input
225 destinations between connectors, the lowest numbered SMA
226 connector is given priority.
227
228 Note that not all input combinations may make sense.
229
230 The 10Mhz reference clock input is currently only valid
231 on SMA1 and may not be combined with other destination sinks.
232
233What: /sys/class/timecard/ocpN/tod_correction
234Date: March 2022
235Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
236Description: (RW) The incoming GNSS signal is in UTC time, and the NMEA
237 format messages do not provide a TAI offset. This sets the
238 correction value for the incoming time.
239
240 If UBX_LS is enabled, this should be 0, and the offset is
241 taken from the UBX-NAV-TIMELS message.
242
243What: /sys/class/timecard/ocpN/ts_window_adjust
244Date: September 2021
245Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
246Description: (RW) When retrieving the PHC with the PTP SYS_OFFSET_EXTENDED
247 ioctl, a system timestamp is made before and after the PHC
248 time is retrieved. The midpoint between the two system
249 timestamps is usually taken to be the SYS time associated
250 with the PHC time. This estimate may be wrong, as it depends
251 on PCI latencies, and when the PHC time was latched
252
253 The attribute value reduces the end timestamp by the given
254 number of nanoseconds, so the computed midpoint matches the
255 retrieved PHC time.
256
257 The initial value is set based on measured PCI latency and
258 the estimated point where the FPGA latches the PHC time. This
259 value may be changed by writing an unsigned integer.
260
261What: /sys/class/timecard/ocpN/ttyGNSS
262What: /sys/class/timecard/ocpN/ttyGNSS2
263Date: September 2021
264Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
265Description: These optional attributes link to the TTY serial ports
266 associated with the GNSS devices.
267
268What: /sys/class/timecard/ocpN/ttyMAC
269Date: September 2021
270Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
271Description: This optional attribute links to the TTY serial port
272 associated with the Miniature Atomic Clock.
273
274What: /sys/class/timecard/ocpN/ttyNMEA
275Date: September 2021
276Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
277Description: This optional attribute links to the TTY serial port
278 which outputs the PHC time in NMEA ZDA format.
279
280What: /sys/class/timecard/ocpN/utc_tai_offset
281Date: September 2021
282Contact: Jonathan Lemon <jonathan.lemon@gmail.com>
283Description: (RW) The DCF and IRIG output signals are in UTC, while the
284 TimeCard operates on TAI. This attribute allows setting the
285 offset in seconds, which is added to the TAI timebase for
286 these formats.
287
288 The offset may be changed by writing an unsigned integer.