42
MI.61xx Manual
General description
Standard generation modes
Standard generation modes
General description
The generated data is replayed from the on-board memory. These modes allows generating waveforms at very high sample rates without the
need to transfer the data into the board’s on-board memory at high speed. These modes are running totally independent from the PC and
don’t need any processing power after being started.
Singleshot mode
The singleshot mode is the most simple output mode for the
Spectrum boards. It simply replays the programmed data
once after detecting the trigger event. The amount of memory
to be replayed can be programmed by software. Any trigger
source can be used to start the output. If output should be start-
ed immediately one can simply use the software trigger capa-
bilities of the board.
Continuous Mode
After detecting the trigger event the programmed data is re-
played continuously. On reaching end of the programmed
memory size the output starts again with the first sample.
There’s no gap in output when switching from the last sample
to the first sample. The output runs until the users stops it by
software. If not stopped the continuous output runs indepen-
dent of any other PC components until the system is shut
down.
Posttrigger Mode
The posttrigger mode is normally only used when starting the
output board together with an acquisiton board.
The data is written to a programmed amount of the on-board
memory (memsize). After starting the board the output will im-
mediately start and continue to loop. At this point the mode is
similar to the continuous mode explained above. After detect-
ing a trigger event, a certain programmed amount of data is
replayed (posttrigger) and then the replay finishes automati-
cally.
Programming
Partitioning the memory
The memory size register defines the length of the data to be replayed. Depending on the mode used this data is replayed once or continu-
ously.
The maximum memsize that can be use for replaying is of course limited by the installed amount of memory and by the number of channels
to be replayed. The following table gives you an overview on the maximum memsize in relation to the installed memory.
Register
Value
Direction
Description
SPC_SINGLESHOT
41000
r/w
Write a „1“ to enable the singleshot mode (a „0“ disables it)
Register
Value
Direction
Description
SPC_SINGLESHOT
41000
r/w
Write a „0“ to disable the singleshot mode
SPC_OUTONTRIGGER
41100
r/w
Write a „1“ to enable the continuous mode
Register
Value
Direction
Description
SPC_SINGLESHOT
41000
r/w
Write a „0“ to disable the singleshot mode
SPC_OUTONTRIGGER
41100
r/w
Write a „0“ to disable the continuous mode
Register
Value
Direction
Description
SPC_MEMSIZE
10000
r/w
Sets the memory size in samples per channel.
SPC_POSTTRIGGER
10100
r/w
Sets the number of samples to be replayed after the trigger event has been detected.
