
Data Device Corporation
62743_pre7_noSA-DB.DOC
www.ddc-web.com
8-07-02
53
For received data, there is also a global circular buffer mode. In this configuration,
the data words received from multiple (or all) subaddresses are stored in a
common circular buffer structure. Like the subaddress circular buffer, the size of
the global circular buffer is programmable, with a range of 128 to 8192 data words.
In addition to helping ensure data sample consistency, the circular buffer options
provide a means of greatly reducing host processor overhead for multi-message
bulk data transfer applications.
End-of-message interrupts may be enabled either globally (following all
messages), following error messages, on a transmit/receive/broadcast subaddress
or mode code basis, or when a circular buffer reaches its midpoint (50% boundary)
or lower (100%) boundary. A pair of interrupt status registers allow the host
processor to determine the cause of all interrupts by means of a single
read
operation.