The operation of a GX515x board is best understood by studying the operation of a single I/O channel.
The figure below displays a simplified block diagram of a single I/O channel. This diagram shows how one channel functions.
Basic I/O Channel Block Diagram
Direction control specifies the way data flows between memory and the I/O channel. The direction must be set before running the board. The default direction is input.
If the direction is set to output, then data will flow from Data Memory, at the Clock (CLK) rate, through an enabled output buffer. If the direction is input, UUT data is latched via the Strobe signal into the input buffer and stored in Data Memory.
The output of all I/O channels must go through an IO/ Module (e.g.GX5910) not shown here.