Contec AI-1608AY-USB User Manual page 46

Memory format
This product uses device buffer transfer mode; it does not require software setup of the memory format.
Device buffer mode
- FIFO format
In the FIFO (First In First Out) format, input data items are read from memory in the same order in
which they were written to the memory. Input data items are fed out of the memory sequentially,
where the oldest one is always read from the memory. The status monitor and application
notification functions are provided, which check and report the state in which the memory has stored
a fixed amount of data or in which the memory has become full.
The FIFO memory is used to obtain all input data from analog input in a short or infinite period of
time.
- Ring format
In the ring format, the memory contains storage areas arranged in a ring. Input data items are written
to the memory sequentially. When it stores data exceeding the limit, it overwrites the area storing
the previous item of input data. The status monitor and application notification functions are
provided, which check and report the state in which data has been written to certain areas of memory.
The ring memory is used to obtain data where conversion has stopped due to some event, usually
without obtaining data in the normal state.
Clock
The sampling clock controls the sampling frequency. You can select either the internal sampling clock,
external sampling clock.
- Internal sampling clock
The clock signal from the on-board clock generator is used.
- External sampling clock
The edge of the digital signal input from an external device is used for the sampling clock.
AI-1608AY-USB
6. Functions
41