| Edge Detection
When enabled sixty-four of the lines can detect logic state changes. A flag is set in a 64-bit register for each input that changes state. The register may be polled to determine which inputs have changed state. The 721 may optionally generate an interrupt whenever state changes occur.
Synchronous I/O
Eight of the 72 I/O channels have special functionality. When programmed as inputs they may be used to latch input data upon command from an external strobe signal. If these eight lines are programmed as outputs an external strobe signal can tri-state/enable the data outputs. For additional flexibility, the data direction of these special I/O lines are programmable in two 4-bit blocks.
External Relays
The optional 721 adapter may be connected to as many as three solid-state relay boards. Each 720RB relay board accepts twenty-four industry standard relays. Software and Manuals
The software development kit, SDK, includes the source code of a sample Visual Basic program and a C-language program that allows setting output lines and reading back their status. A 32-bit Windows NT/2000 DLL is also supplied.
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