Pulse from threshold crossing
This on-line script is written for use with Spike2 for Windows version 3 and later.
Before running the script, you need to ensure a suitable sampling configuration is set. This must contain at least one waveform channel. If you select to output a TTL pulse upon threshold detection, you may choose to set up an event or level channel for testing purposes.
To run the script, go to the script menu and select Run script. If the script is already loaded, it will appear in the menu; otherwise select Load and run which will generate a file selection dialog from which you should find and load the threspul.s2s script.
When the script is run, a dialog will appear, from which you set the various required settings:
Input channel - Waveform channel on which to base threshold crossing timing
Threshold - Direction of threshold crossing. Positive (rising) or negative (falling)
Action - TTL pulse and/or memory channel marker
When OK is pressed in this dialog the script will open a new data file, ready to sample, with a horizontal cursor positioned on the selected waveform channel. This should be positioned at a reasonable starting level for the threshold, and the OK button pressed to continue.
When ready to sample, a toolbar is displayed from which the data sampling is controlled.
Quit - Quit the script and close down the toolbar
Sample start - Commence data sampling
Sample stop - Stop sampling. This button is disabled until sampling begins
New file - Close current file and open a new file ready to sample
The default TTL output gives a pulse of duration 1ms from digital output 0 (bit 8) of the 1401 interface. The overall speed of the sequence and the pulse duration and selection of output bit can be edited in the pulse.pls file if required.
If TTL output is selected, the script writes a Spike2 output sequence file which is stored with a default name (pulse.pls) in the sequence sub-directory of the main Spike2 directory where the application is stored (e.g. C:\Spike4\Sequence\pulse.pls).
Memory channel marker
If Memory channel marker is selected, a new temporary channel is created and displayed in the data file. Each time the threshold is crossed, markers are imported into this channel at a position as close as possible to the actual threshold crossing.
This channel is temporary and must be written to a permanent channel if it is to be saved with the recorded data file. To do this go to the Analysis menu and select Memory buffer then Write to channel. From the dialog you can select an empty channel into which this data will be written.