Spectrum Brands MC.31XX 用户手册

Option Timestamp

Reading out timestamp data

(c) Spectrum GmbH

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Reading out all the timestamps with SpcGetData
When using the function SpcGetData the data stored in the timestamp FIFO will be read out in one block by the driver. The usage of the 
function SpcGetData is described in the relating section earlier in this manual. The following list does only show the different parameters in 
a very short way:

•  nr: Number of the board (Windows). Linux users please refer to the Driver section for differences using linux.
•  ch: Channel to be read out. Must be set to CH_TIMESTAMP (9999) to access timestamp FIFO.
•  start: [Windows only:] Differing from the standard use, this parameter gives back the number of actually read timestamps and therefore 

needs to be a pointer. Please refer to the example at the end of this chapter. Under linux please use the SPC_TIMESTAMP_COUNT regis-
ter instead and program the „start“ parameter to zero.

•  len: Number of timestamps that fit in the data buffer and so defines the number of timestamps to be read out.
•  data: Huge buffer for the read out timestamps, that must have at least enough space for 8*len bytes.

It might be that you try to read out more timestamps than there actually are in the timestamp FIFO bacause you don’t know how many trigger 
events have been detected. Please make use of the value given back by the parameter start to get to know what parts of your buffer contain 
valid timestamps.

Each timestamp is 56 bit long and internally mapped  to 64 bit (8 bytes). The counter value contains the number of clocks that have been 
recorded with the currently used sample rate since the last counter-reset has been done. The matching time can easily be calculated as de-
scribed in the general information section at the beginning of this chapter.

The values the counter is counting and that are stored in the timestamp FIFO represent the moments the trigger event occures internally. Com-
pared to the real external trigger event, these values are delayed. The delay is depending on the actual sample rate, the number of activated 
channels and the used trigger mode. This delay can be ignored, as it will be identically for all recordings with the same setup.

SPC_TIMESTAMP_COUNT

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r

Return the number of timestamps that have been read be the prior SpcGetData call. Needs only to be 
used under Linux.

Standard/StartReset

Normal / Multiple Recording

Trigger 0
LOW part

Trigger 0
HIGH part

Trigger 1
LOW part

Trigger 1
HIGH part

Trigger 2
LOW part

Trigger 2
HIGH part

Standard/StartReset

Gated Sampling

Gate Start 0
LOW part

Gate Start 0
HIGH part

Gate End 0
LOW part

Gate End 0
HIGH part

Gate Start 1
LOW part

Gate Start 1
HIGH part

RefClock

Normal / Multiple Recording

Trigger 0
Counter value

Trigger 0
Seconds

Trigger 1
Counter value

Trigger 1
Seconds

Trigger 2
Counter value

Trigger 2
Seconds

RefClock

Gated Sampling

Gate Start 0
Counter value

Gate Start 0
Seconds

Gate End 0
Counter value

Gate End 0
Seconds

Gate Start 1
Counter value

Gate Start 1
Seconds