xem_if.v

This module is an interface between logic and the Opal Kelly FrontPanel HDL library. It provides connections to the Opal Kelly wire ins and outs, trigger ins and outs, pipe ins and outs of both the throttled and unthrottle kind. There is also a multiplexor to loop back wire ins. All 512 wire-in bits, all 512 wire-out bits, two pipe ins, and two pipe outs are instantiated by this module.

Ports | Parameters | Notes

Host connections

hi_in	input	Host-interface inputs.
hi_out	input	Host-interface outputs.
hi_inout	input	Bidirectional host-interface signals.

User ports

ti_clk	output	Host-interface clock used by logic.
wi	output	512-bit wire in.
wo	input	512-bit wire out.
ep40trig	output	16-bit trigger in.
ep41trig	output	16-bit trigger in.
ep60trig	input	16-bit trigger out.
btpipeI_write	output	Tells logic that data are available in `btpipeI_data`.
btpipeI_data	output	Pipe-in data port associated with `btpipeI_write`.
btpipeI_write_83	output	Throttled pipe-in write signal.
btpipeI_block_83	output	Throttled pipe-in strobe.
btpipeI_data_83	input	Throttled pipe-in data.
ep83_rdy	input	Used by logic to tell the interface that logic is ready to receive data on `btpipeI_data_83`.
btpipeO_read	output	Tells logic that the interface is reading data from `btpipeO_data`.
btpipeO_data	input	The pipe-out data port associated with `btpipeO_read`.
epB1_read	output	Tells logic that the interface is reading data from `epB_din`.
epB1_din	input	The pipe data port associated with `epB1_read`.
readbacks	input	A 512-bit expansion of the wire-in readback.

Parameters

wd	Width of the host-interface data path (default 16).

Notes

The wire-in readback data bits occupy the wire-out bits wo[31:16] (16 bits). The six-bit selector is taken from the wire-in bits wi[42:37], which selects one of 64 16-bit word fields of wi and readbacks. These bit fields should not be used for another purpose.
To read out a 16-bit field of wi or readback via a host computer, using FrontPanel first set the selector field selecting the bit field to be read out, then read out the wire-out field.
The FrontPanel user guide explains how to use pipes and throttled pipes in logic, providing timing diagrams.
As of this writing, we are using FrontPanel firmware version 3.1, and FrontPanel version 3.0.11.