OpenCompute TimeCard sysfs ABI | Linux 6.18.37

요약·해설과 원문, 전문 번역을 서로 분리했습니다. API 이름, symbol, source path는 원문 표기를 사용합니다.

1. 요약·해설

원문의 핵심 논리와 kernel programming 관점의 보충 설명입니다. 아래의 전문 번역과는 별도로 작성했습니다.

PHC source와 SMA capabilities

sysfs-timecard:1-78

Indexed TimeCard가 PHC adjustment source와 SMA input destinations/output sources를 나열하고 current clock source를 선택합니다.

Atomic disciplining과 frequency I/O

sysfs-timecard:79-169

Atomic-clock drift·offset, measurement counters와 programmable generators의 period·duty·phase·polarity·start status를 제공합니다.

GNSS와 associated devices

sysfs-timecard:170-232

GNSS sync, IRIG-B mode, I2C·PPS·PTP links와 four SMA connector routing을 관리합니다.

UTC/TAI와 timestamp correction

sysfs-timecard:233-260

GNSS UTC correction과 PCI/FPGA latency에 따른 PHC timestamp-window midpoint를 조정합니다.

TTY links와 UTC output offset

sysfs-timecard:261-293

GNSS·atomic-clock·NMEA TTY names를 제공하고 TAI timebase에서 DCF·IRIG UTC output을 만들 offset seconds를 설정합니다.

2. 영어 원문 전체

번역 기준이 된 Linux v6.18.37 원문입니다. 줄 번호는 이 버전의 파일 좌표입니다.

원문 전체 펼치기

1 What: /sys/class/timecard/

2 Date: September 2021

3 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

4 Description: This directory contains files and directories

5 providing a standardized interface to the ancillary

6 features of the OpenCompute timecard.

8 What: /sys/class/timecard/ocpN/

9 Date: September 2021

10 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

11 Description: This directory contains the attributes of the Nth timecard

12 registered.

14 What: /sys/class/timecard/ocpN/available_clock_sources

15 Date: September 2021

16 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

17 Description: (RO) The list of available time sources that the PHC

18 uses for clock adjustments.

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 ==== =================================================

28 What: /sys/class/timecard/ocpN/available_sma_inputs

29 Date: September 2021

30 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

31 Description: (RO) Set of available destinations (sinks) for a SMA

32 input signal.

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 ===== ================================================

51 What: /sys/class/timecard/ocpN/available_sma_outputs

52 Date: May 2021

53 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

54 Description: (RO) Set of available sources for a SMA output signal.

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 ===== ================================================

72 What: /sys/class/timecard/ocpN/clock_source

73 Date: September 2021

74 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

75 Description: (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.

79 What: /sys/class/timecard/ocpN/clock_status_drift

80 Date: March 2022

81 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

82 Description: (RO) Contains the current drift value used by the firmware

83 for internal disciplining of the atomic clock.

85 What: /sys/class/timecard/ocpN/clock_status_offset

86 Date: March 2022

87 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

88 Description: (RO) Contains the current offset value used by the firmware

89 for internal disciplining of the atomic clock.

91 What: /sys/class/timecard/ocpN/freqX

92 Date: March 2022

93 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

94 Description: (RO) Optional directory containing the sysfs nodes for

95 frequency counter <X>.

97 What: /sys/class/timecard/ocpN/freqX/frequency

98 Date: March 2022

99 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

100 Description: (RO) Contains the measured frequency over the specified

101 measurement period.

102

103 What: /sys/class/timecard/ocpN/freqX/seconds

104 Date: March 2022

105 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

106 Description: (RW) Specifies the number of seconds from 0-255 that the

107 frequency should be measured over. Write 0 to disable.

108

109 What: /sys/class/timecard/ocpN/genX

110 Date: March 2022

111 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

112 Description: (RO) Optional directory containing the sysfs nodes for

113 frequency generator <X>.

114

115 What: /sys/class/timecard/ocpN/genX/duty

116 Date: March 2022

117 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

118 Description: (RO) Specifies the signal duty cycle as a percentage from 1-99.

119

120 What: /sys/class/timecard/ocpN/genX/period

121 Date: March 2022

122 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

123 Description: (RO) Specifies the signal period in nanoseconds.

124

125 What: /sys/class/timecard/ocpN/genX/phase

126 Date: March 2022

127 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

128 Description: (RO) Specifies the signal phase offset in nanoseconds.

129

130 What: /sys/class/timecard/ocpN/genX/polarity

131 Date: March 2022

132 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

133 Description: (RO) Specifies the signal polarity, either 1 or 0.

134

135 What: /sys/class/timecard/ocpN/genX/running

136 Date: March 2022

137 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

138 Description: (RO) Either 0 or 1, showing if the signal generator is running.

139

140 What: /sys/class/timecard/ocpN/genX/start

141 Date: March 2022

142 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

143 Description: (RO) Shows the time in <sec>.<nsec> that the signal generator

144 started running.

145

146 What: /sys/class/timecard/ocpN/genX/signal

147 Date: March 2022

148 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

149 Description: (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

170 What: /sys/class/timecard/ocpN/gnss_sync

171 Date: September 2021

172 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

173 Description: (RO) Indicates whether a valid GNSS signal is received,

174 or when the signal was lost.

175

176 What: /sys/class/timecard/ocpN/i2c

177 Date: September 2021

178 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

179 Description: This optional attribute links to the associated i2c device.

180

181 What: /sys/class/timecard/ocpN/irig_b_mode

182 Date: September 2021

183 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

184 Description: (RW) An integer from 0-7 indicating the timecode format

185 of the IRIG-B output signal: B00<n>

186

187 What: /sys/class/timecard/ocpN/pps

188 Date: September 2021

189 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

190 Description: This optional attribute links to the associated PPS device.

191

192 What: /sys/class/timecard/ocpN/ptp

193 Date: September 2021

194 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

195 Description: This attribute links to the associated PTP device.

196

197 What: /sys/class/timecard/ocpN/serialnum

198 Date: September 2021

199 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

200 Description: (RO) Provides the serial number of the timecard.

201

202 What: /sys/class/timecard/ocpN/sma1

203 What: /sys/class/timecard/ocpN/sma2

204 What: /sys/class/timecard/ocpN/sma3

205 What: /sys/class/timecard/ocpN/sma4

206 Date: September 2021

207 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

208 Description: (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

233 What: /sys/class/timecard/ocpN/tod_correction

234 Date: March 2022

235 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

236 Description: (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

243 What: /sys/class/timecard/ocpN/ts_window_adjust

244 Date: September 2021

245 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

246 Description: (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

261 What: /sys/class/timecard/ocpN/tty

262 Date: August 2024

263 Contact: Vadim Fedorenko <vadim.fedorenko@linux.dev>

264 Description: (RO) Directory containing the sysfs nodes for TTY attributes

265

266 What: /sys/class/timecard/ocpN/tty/ttyGNSS

267 What: /sys/class/timecard/ocpN/tty/ttyGNSS2

268 Date: August 2024

269 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

270 Description: (RO) These optional attributes contain names of the TTY serial

271 ports associated with the GNSS devices.

272

273 What: /sys/class/timecard/ocpN/tty/ttyMAC

274 Date: August 2024

275 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

276 Description: (RO) This optional attribute contains name of the TTY serial

277 port associated with the Miniature Atomic Clock.

278

279 What: /sys/class/timecard/ocpN/tty/ttyNMEA

280 Date: August 2024

281 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

282 Description: (RO) This optional attribute contains name of the TTY serial

283 port which outputs the PHC time in NMEA ZDA format.

284

285 What: /sys/class/timecard/ocpN/utc_tai_offset

286 Date: September 2021

287 Contact: Jonathan Lemon <jonathan.lemon@gmail.com>

288 Description: (RW) The DCF and IRIG output signals are in UTC, while the

289 TimeCard operates on TAI. This attribute allows setting the

290 offset in seconds, which is added to the TAI timebase for

291 these formats.

292

293 The offset may be changed by writing an unsigned integer.

294

3. 한국어 전문 번역

영어 원문의 문단 순서와 의미를 유지한 전체 번역입니다. 코드, 함수명, symbol과 URL은 원문 표기를 유지합니다.

OpenCompute TimeCard sysfs ABI: timecard

1-7

항목	한국어 전문 번역
What	/sys/class/timecard/
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/` directory에는 OpenCompute TimeCard ancillary features에 대한 standardized interface를 제공하는 files와 directories가 들어 있습니다.

OpenCompute TimeCard sysfs ABI: ocpN

8-13

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/` directory에는 register된 N번째 TimeCard의 attributes가 들어 있습니다.

OpenCompute TimeCard sysfs ABI: available clock sources

14-27

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/available_clock_sources
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/available_clock_sources`는 PHC가 clock adjustment에 사용할 수 있는 time sources의 read-only list입니다. `NONE`은 adjustment 없음, default `PPS`는 PPS1 selector, `TOD`는 GNSS/TOD module, `IRIG`는 external IRIG-B signal, `DCF`는 external DCF signal에서 adjustment를 받습니다.

TimeCard PHC clock sources

ValuePHC adjustment source

NONENo adjustments

PPSPPS1 selector (default)

TODGNSS/TOD module

IRIGExternal IRIG-B signal

DCFExternal DCF signal

available_clock_sources의 adjustment sources를 보존합니다.

OpenCompute TimeCard sysfs ABI: available sma inputs

28-50

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/available_sma_inputs
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/available_sma_inputs`는 SMA input signal이 갈 수 있는 read-only destinations(sinks) set입니다. `10Mhz`는 10Mhz reference clock, `PPS1`·`PPS2`는 각 PPS selector, `TS1`~`TS4`는 timestamper 1~4, `IRIG`·`DCF`는 각 module, `FREQ1`~`FREQ4`는 frequency counter 1~4로 signal을 보냅니다. `None`은 signal input을 disable합니다.

TimeCard SMA input destinations

ValueDestination

10Mhz10Mhz reference clock

PPS1 / PPS2PPS selector 1 / 2

TS1 / TS2 / TS3 / TS4Timestamper 1 / 2 / 3 / 4

IRIG / DCFIRIG-B / DCF module

FREQ1 / FREQ2 / FREQ3 / FREQ4Frequency counter 1 / 2 / 3 / 4

NoneDisable signal input

SMA input signal이 향할 수 있는 sinks입니다.

OpenCompute TimeCard sysfs ABI: available sma outputs

51-71

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/available_sma_outputs
Date	2021년 5월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/available_sma_outputs`는 SMA output signal에 사용할 수 있는 read-only sources set입니다. `10Mhz` reference clock, PHC PPS, Miniature Atomic Clock `MAC` PPS, `GNSS1`·`GNSS2` PPS, PHC의 `IRIG`·`DCF` format, frequency generators `GEN1`~`GEN4`, constant `GND`와 `VCC`를 제공합니다.

TimeCard SMA output sources

ValueSource

10Mhz10Mhz reference clock

PHCPHC PPS

MACMiniature Atomic Clock PPS

GNSS1 / GNSS2GNSS module 1 / 2 PPS

IRIG / DCFPHC in IRIG-B / DCF format

GEN1 / GEN2 / GEN3 / GEN4Frequency generator 1 / 2 / 3 / 4

GND / VCCConstant GND / VCC

SMA output에 route할 수 있는 clock, PPS, formats와 logic levels입니다.

OpenCompute TimeCard sysfs ABI: clock source

72-78

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/clock_source
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/clock_source`는 PHC가 현재 사용하는 synchronization source를 담는 read/write attribute입니다. `available_clock_sources`에 나열된 value를 써서 변경합니다.

OpenCompute TimeCard sysfs ABI: clock status drift

79-84

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/clock_status_drift
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/clock_status_drift`는 firmware가 atomic clock internal disciplining에 사용하는 current drift value를 담는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: clock status offset

85-90

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/clock_status_offset
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/clock_status_offset`은 firmware가 atomic clock internal disciplining에 사용하는 current offset value를 담는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: freqX

91-96

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/freqX
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/freqX`는 frequency counter `<X>`의 sysfs nodes를 담는 optional read-only directory입니다.

TimeCard frequency counter

AttributeAccessMeaning

frequencyRead-onlyMeasured frequency

secondsRead/writeMeasurement period 0..255 seconds

DisableWrite 0 to seconds.

Measurement value와 configurable duration을 비교합니다.

OpenCompute TimeCard sysfs ABI: frequency

97-102

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/freqX/frequency
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/freqX/frequency`는 specified measurement period 동안 측정한 frequency를 담는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: seconds

103-108

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/freqX/seconds
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/freqX/seconds`는 frequency measurement duration을 `0-255` seconds로 지정하는 read/write attribute입니다. `0`을 쓰면 disable합니다.

OpenCompute TimeCard sysfs ABI: genX

109-114

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX`는 frequency generator `<X>`의 sysfs nodes를 담는 optional read-only directory입니다.

TimeCard frequency-generator attributes

AttributeUnit or values

duty1..99 percent

periodNanoseconds

phaseNanoseconds

polarity0 or 1

running0 or 1

start<sec>.<nsec>

Signal waveform와 running status fields입니다.

OpenCompute TimeCard sysfs ABI: duty

115-119

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/duty
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/duty`는 signal duty cycle을 `1-99` percent로 지정하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: period

120-124

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/period
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/period`는 signal period를 nanoseconds로 지정하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: phase

125-129

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/phase
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/phase`는 signal phase offset을 nanoseconds로 지정하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: polarity

130-134

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/polarity
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/polarity`는 signal polarity를 `1` 또는 `0`으로 지정하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: running

135-139

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/running
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/running`은 signal generator가 running인지 `0` 또는 `1`로 표시하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: start

140-145

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/start
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/start`는 signal generator가 running을 시작한 time을 `<sec>.<nsec>` format으로 표시하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: signal

146-169

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/genX/signal
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/genX/signal`은 signal generator를 start하고 current status를 요약하는 read/write attribute입니다. `period [duty [phase [polarity]]]` 순서로 period와 optional values를 씁니다. 생략한 values는 다른 sysfs nodes에서 확인할 수 있는 current settings를 default로 사용합니다. `echo 500000000 > signal`은 1/2-second period, `echo 1000000 40 100 > signal`은 period·duty·phase를 설정하고, `echo 0 > signal`은 generator를 끕니다. Period와 phase는 nanoseconds, duty는 `1-99` percent, polarity는 `1` 또는 `0`입니다. Read하면 `period duty phase polarity start_time`을 반환합니다.

TimeCard signal write syntax

PositionFieldUnit or range

1periodNanoseconds

2duty1..99 percent

3phaseNanoseconds

4polarity0 or 1

Readbackperiod duty phase polarity start_time

Optional fields는 오른쪽부터 생략하며 current settings를 default로 사용합니다.

period [duty [phase [polarity]]]
echo 500000000 > signal
echo 1000000 40 100 > signal
echo 0 > signal

OpenCompute TimeCard sysfs ABI: gnss sync

170-175

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/gnss_sync
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/gnss_sync`는 valid GNSS signal을 받고 있는지 또는 signal을 잃은 time을 나타내는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: i2c

176-180

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/i2c
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/i2c`는 associated I2C device로 연결되는 optional attribute입니다.

OpenCompute TimeCard sysfs ABI: irig b mode

181-186

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/irig_b_mode
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/irig_b_mode`는 IRIG-B output signal의 timecode format `B00<n>`을 나타내는 `0-7` integer read/write attribute입니다.

OpenCompute TimeCard sysfs ABI: pps

187-191

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/pps
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/pps`는 associated PPS device로 연결되는 optional attribute입니다.

OpenCompute TimeCard sysfs ABI: ptp

192-196

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/ptp
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/ptp`는 associated PTP device로 연결되는 attribute입니다.

OpenCompute TimeCard sysfs ABI: serialnum

197-201

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/serialnum
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/serialnum`은 TimeCard serial number를 제공하는 read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: sma1, sma2, sma3, sma4

202-232

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/sma1 ; /sys/class/timecard/ocpN/sma2 ; /sys/class/timecard/ocpN/sma3 ; /sys/class/timecard/ocpN/sma4
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/sma1`, `sma2`, `sma3`, `sma4`는 associated SMA connectors의 signal direction과 sink/source를 지정하는 read/write attributes입니다. Display는 input/output direction prefix가 붙은 space-separated signal list입니다. 지원되는 경우 `in:` 또는 `out:` prefix로 direction을 바꿀 수 있고 prefix가 없으면 direction은 유지됩니다. Output은 `available_sma_outputs` value 하나로 변경합니다. Input destinations는 `available_sma_inputs` values 여러 개를 spaces로 구분해 변경합니다. Connectors 사이 destination이 duplicate이면 가장 낮은 번호 SMA connector가 priority를 가집니다. 모든 input combination이 의미 있지는 않습니다. `10Mhz` reference-clock input은 현재 SMA1에서만 valid하며 다른 destination sinks와 결합할 수 없습니다.

TimeCard SMA routing

Write out:<source>Choose one available_sma_outputs valueRoute source to connector

Write in:<sink ...>Choose available_sma_inputs valuesRoute input to destinations

Duplicate destinationLowest-numbered SMA wins

Direction prefix와 source/destination lists가 connector routing을 결정합니다.

10Mhz reference-clock input은 SMA1에서만 valid하며 다른 destination sink와 결합할 수 없습니다.

OpenCompute TimeCard sysfs ABI: tod correction

233-242

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/tod_correction
Date	2022년 3월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/tod_correction`은 incoming GNSS UTC time에 적용할 correction value를 설정하는 read/write attribute입니다. NMEA messages는 TAI offset을 제공하지 않습니다. `UBX_LS`가 enabled이면 이 value는 `0`이어야 하고 offset은 `UBX-NAV-TIMELS` message에서 가져옵니다.

TimeCard time corrections

AttributeDirectionPurpose

tod_correctionGNSS inputCorrect incoming UTC without NMEA TAI offset

utc_tai_offsetDCF/IRIG outputAdd seconds to TAI timebase for UTC

UBX_LS enabledtod_correction must be 0; use UBX-NAV-TIMELS offset.

GNSS input와 DCF/IRIG output의 UTC·TAI handling을 구분합니다.

OpenCompute TimeCard sysfs ABI: ts window adjust

243-260

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/ts_window_adjust
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/ts_window_adjust`는 `PTP_SYS_OFFSET_EXTENDED` ioctl로 PHC를 읽을 때 system timestamp window를 nanoseconds 단위로 조정합니다. PHC read 전후 system timestamps의 midpoint를 PHC time과 대응하는 SYS time으로 보통 사용하지만 PCI latencies와 FPGA latch timing 때문에 estimate가 틀릴 수 있습니다. Attribute value만큼 end timestamp를 줄여 computed midpoint를 retrieved PHC time에 맞춥니다. Initial value는 measured PCI latency와 estimated FPGA latch point를 기반으로 하며 unsigned integer write로 바꿀 수 있습니다.

PHC timestamp-window adjustment

System timestamp before PHC readRead latched PHC timeSystem timestamp after readCompute midpoint

Subtract ts_window_adjust from end timestampRecompute midpointAlign SYS and PHC time

End timestamp correction shifts the system midpoint toward the actual PHC latch time.

OpenCompute TimeCard sysfs ABI: tty

261-265

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/tty
Date	2024년 8월
KernelVersion
Contact	Vadim Fedorenko <vadim.fedorenko@linux.dev>
Description	`/sys/class/timecard/ocpN/tty`는 TTY attributes의 sysfs nodes를 담는 read-only directory입니다.

TimeCard associated TTY attributes

AttributeAssociated device or output

ttyGNSS / ttyGNSS2GNSS devices

ttyMACMiniature Atomic Clock

ttyNMEAPHC time in NMEA ZDA format

Optional serial-port names와 transported signal을 정리합니다.

OpenCompute TimeCard sysfs ABI: ttyGNSS, ttyGNSS2

266-272

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/tty/ttyGNSS ; /sys/class/timecard/ocpN/tty/ttyGNSS2
Date	2024년 8월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/tty/ttyGNSS`와 `ttyGNSS2`는 GNSS devices와 연결된 TTY serial-port names를 담는 optional read-only attributes입니다.

OpenCompute TimeCard sysfs ABI: ttyMAC

273-278

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/tty/ttyMAC
Date	2024년 8월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/tty/ttyMAC`은 Miniature Atomic Clock과 연결된 TTY serial-port name을 담는 optional read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: ttyNMEA

279-284

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/tty/ttyNMEA
Date	2024년 8월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/tty/ttyNMEA`는 PHC time을 NMEA ZDA format으로 output하는 TTY serial-port name을 담는 optional read-only attribute입니다.

OpenCompute TimeCard sysfs ABI: utc tai offset

285-293

항목	한국어 전문 번역
What	/sys/class/timecard/ocpN/utc_tai_offset
Date	2021년 9월
KernelVersion
Contact	Jonathan Lemon <jonathan.lemon@gmail.com>
Description	`/sys/class/timecard/ocpN/utc_tai_offset`은 TimeCard의 TAI timebase에 더해 DCF와 IRIG output을 UTC로 만드는 offset seconds를 설정하는 read/write attribute입니다. Unsigned integer를 써서 변경합니다.