BUFGTS

Global Three-State Input Buffer

BUFGTS, an XC9000-specific global buffer, distributes global output-enable signals throughout the output pad drivers of an XC9000 device. Global Three-State (GTS) control pins are available on XC9000 devices; consult device data sheets for availability.

BUFGTS always acts as an input buffer. To use it in a schematic, connect the input of the BUFGTS symbol to an IPAD or an IOPAD representing the GTS signal source. GTS signals generated on-chip must be passed through an OBUF-type buffer before they are connected to BUFGTS.

For global 3-state control, the output of BUFGTS normally connects to the E input of a 3-state output buffer symbol, OBUFE. The global 3-state control signal may pass through an inverter or control an OBUFT symbol to perform an active-low output-enable. The same 3-state control signal may even be used both inverted and non-inverted to enable alternate groups of device outputs. The output of BUFGTS may also be used as an ordinary input signal to other logic elsewhere in the design. Each BUFGTS can control any number of output buffers in a design.