Spectrum M2p.59 Series, Hardware Manual, Page: 158 / 190

158 (c) Spectrum Instrumentation GmbH
Timestamp modes Timestamps
Example for setting timestamp mode:
The timestamp mode must consist of one of the mode constants, one of the counter and one of the feature constants:
Timestamp modes
Standard mode
In standard mode the timestamp counter is set to zero once by writing the TS_RESET command to the command register. After that command
the counter counts continuously independent of start and stop of acquisition. The timestamps of all recorded trigger events are referenced to
this common zero time. With this mode you can calculate the exact time difference between different recordings and also within one acqui -
sition (if using Multiple Recording or Gated Sampling).
The following table shows the valid values that can be written to the timestamp command register for this mode:
Please keep in mind that this mode only work sufficiently as long as you don’t change the sampling rate
between two acquisitions that you want to compare.
StartReset mode
In StartReset mode the timestamp counter is set to zero on every start of the card. After starting the card the counter counts continuously. The
timestamps of one recording are referenced to the start of the recording. This mode is very useful for Multiple Recording and Gated Sampling
(see according chapters for detailed information on these two optional modes).
// setting timestamp mode to standard using internal clocking
spcm_dwSetParam_i32 (hDrv, SPC_TIMESTAMP_CMD, SPC_TSMODE_STANDARD | SPC_TSCNT_INTERNAL | SPC_TSFEAT_NONE);
// setting timestamp mode to start reset mode using internal clocking
spcm_dwSetParam_i32 (hDrv, SPC_TIMESTAMP_CMD, SPC_TSMODE_STARTRESET | SPC_TSCNT_INTERNAL | SPC_TSFEAT_NONE);
// setting timestamp mode to standard using external reference clock with positive edge
spcm_dwSetParam_i32 (hDrv, SPC_TIMESTAMP_CMD, SPC_TSMODE_STANDARD | SPC_TSCNT_REFCLOCKPOS | SPC_TSFEAT_NONE);
Table 92: Spectrum AP: timestamp commands for standard mode
Register Value Direction Description
SPC_TIMESTAMP_CMD 47000 read/write Programs a timestamp mode and performs commands as listed below
SPC_TSMODE_DISABLE 0 Timestamp is disabled.
SPC_TS_RESET 1h The timestamp counter is set to zero
SPC_TSMODE_STANDARD 2h Standard mode, counter is reset by explicit reset command.
SPC_TSCNT_INTERNAL 100h Counter is running with complete width on sampling clock
Image 72: drawing of timestamp acquisition in standard mode in relation to card start and trigger detection
Image 73: drawing of timestamp acquisition in start-reset mode in relation to card start and trigger detection