Files
UHD-Fairwaves/fpga/control_lib/s6_icap_wb.v
Josh Blum 0a3dd778d0 umtrx: slow down icap clock, this image resets reliably
Looks like icap clk from the pll is shared with the frontend clock.
So instead I opted to divide the icap clk down inside s6_icap_wb.v.
The image checked in reset reliably after many trials,
which is a good sign that this may be an acceptable fix.
2015-04-01 00:45:00 -07:00

71 lines
2.1 KiB
Verilog

//
// Copyright 2013 Andrew Karpenkov, Fairwaves LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
//ATTENTION!! Maximum ICAP clock in Spartan 6 is 20 MHz!!!
module s6_icap_wb
(input clk, input clk_icap, input reset,
input cyc_i, input stb_i, input we_i, output reg ack_o,
input [31:0] dat_i, output reg[31:0] dat_o);//, output [31:0] debug_out);
reg slow_clk_icap;
always @(posedge clk_icap) slow_clk_icap <= ~slow_clk_icap;
wire BUSY, CE, WRITE;
wire[31:0] s1_dat_i;
reg[31:0] s_dat_o;
wire[31:0] s1_dat_o;
assign s1_dat_o[31:16] = 16'd0;
wire full, empty;
fifo_xlnx_16x40_2clk icap_fifo
(.rst(reset),
.wr_clk(clk), .din(dat_i), .wr_en(we_i & stb_i & ~ack_o & ~full), .full(full),
.rd_clk(slow_clk_icap), .dout(s1_dat_i), .rd_en(~empty), .empty(empty));
assign WRITE = empty;
assign CE = empty;
ICAP_SPARTAN6 ICAP_SPARTAN6_inst
(.BUSY(BUSY), // Busy output
.O(s1_dat_o[15:0]), // 16-bit data output
.CE(CE), // Clock enable input
.CLK(slow_clk_icap), // Clock input
.I(s1_dat_i[15:0]), // 16-bit data input
.WRITE(WRITE) // Write input
);
//cross back to Wishbone clock domain
always @(posedge clk)
if (reset)
begin
s_dat_o <= 32'd0;
dat_o <= 32'd0;
ack_o <= 1'b0;
end
else
begin
s_dat_o <= s1_dat_o;
dat_o[15:0] <= s_dat_o[15:0];
ack_o <= stb_i & ~ack_o;
end
endmodule // s6_icap_wb