Period Timer

BitScope can measure elapsed time between events ranging from 10 us to more than 53 years !

It may be used to measure one-off events or periodic signal frequencies that are too low to be captured using trace mode TM8 frequency measurement.

The Period P command is used for these purposes.

The events delimiting the measured time period may be selected from the same sources as TM8, and also from the trigger comparator source.

Period capture is not a trace mode. Instead, it is implemented by incrementing 48 bit counter during a programmed number of positive edge transition of the source where this number is between 1 and 256 as programmed to the Period Pule Count register R23.

The total time period elapsed during all signal pre-programmed signal edges is returned on completion as:

PERIOD = (PC * 15) + 9 + U

where:

PERIOD	Total elapsed period (in PIC cycles).
PC	48 bit Period Counter returned on completion of the P command.
U	Measurement uncertainty (± 10 PIC cycles).

The format of the returned period count is:

PC

=>

<CR>HHHHHHHHHHHH<CR> where H is one 12 ASCII encoded hex digits

By programming the trigger comparator as the input, the precise period between one or more analogue signal or logic events may be measured. Similarly, frequencies ranging from 100 kHz down to fractions of 1 Hz may be measured to an accuracy of ± 4 uS.