Measurement Computing Digital232 - Manual (Page 19)

Section 2 Getting Started
2.11
TIMING DIAGRAM FOR STROBE OUTPUT
2.3.3.3 External Data Ready [EDR] (Pin 46)
The External Data Ready [EDR] line is an edge sensitive input which is
used to latch input data. It is used in conjunction with the Data Ready
command (R1). The EDR signal must be at least 1 microsecond wide and must
have a rise and fall time of less than one microsecond. The EDR line is
normally rising-edge sensitive but can be programmed with the Invert
command (I32) to be falling-edge sensitive. Refer to the following diagram for
timing relationships.
When using the EDR line the Digital232 will only output data when the
EDR line transitions.
2.3.3.4 Inhibit (Pin 44)
The Inhibit output is asserted while data on the selected I/O port is being
read into the I/O port buffer. This line is normally active high but may be
programmed active low by the Invert command (I1). The Inhibit line can be
programmed independent of any I/O operations with the Inhibit command
(Qn). Refer to the following diagram for timing relationships.
The Inhibit line is asserted once for each data read operation for all format
[Fn] modes.