Merged r7611:7614 from jcorgan/gpio into trunk. Adds custom

FPGA build for streaming digital I/O to/from GPIO pins through LSB of I and Q
datastreams, with example programs of use.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@7618 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 55 insertions, 0 deletions

diff --git a/gr-gpio/src/fpga/lib/io_pins.v b/gr-gpio/src/fpga/lib/io_pins.v
new file mode 100644
index 000000000..9d857902f
--- /dev/null
+++ b/gr-gpio/src/fpga/lib/io_pins.v
@@ -0,0 +1,55 @@
+// -*- verilog -*-
+//
+//  USRP - Universal Software Radio Peripheral
+//
+//  Copyright (C) 2005,2006 Matt Ettus
+//  Copyright (C) 2008 Corgan Enterprises 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 2 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, write to the Free Software
+//  Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA
+//
+
+`include "../../../../usrp/firmware/include/fpga_regs_common.v"
+`include "../../../../usrp/firmware/include/fpga_regs_standard.v"
+
+module io_pins
+  ( inout wire [15:0] io_0, inout wire [15:0] io_1, inout wire [15:0] io_2, inout wire [15:0] io_3,
+    input wire [15:0] reg_0, input wire [15:0] reg_1, input wire [15:0] reg_2, input wire [15:0] reg_3,
+    input wire [15:0] io_0_force_output, input wire [15:0] io_2_force_output, 
+    input wire [15:0] io_1_force_input,  input wire [15:0] io_3_force_input,
+    input clock, input rx_reset, input tx_reset,
+    input [6:0] serial_addr, input [31:0] serial_data, input serial_strobe);
+   
+   reg [15:0] io_0_oe,io_1_oe,io_2_oe,io_3_oe;
+   
+   bidir_reg bidir_reg_0 (.tristate(io_0),.oe(io_0_oe |   io_0_force_output),.reg_val(reg_0));
+   bidir_reg bidir_reg_1 (.tristate(io_1),.oe(io_1_oe & (~io_1_force_input)),.reg_val(reg_1));
+   bidir_reg bidir_reg_2 (.tristate(io_2),.oe(io_2_oe |   io_2_force_output),.reg_val(reg_2));
+   bidir_reg bidir_reg_3 (.tristate(io_3),.oe(io_3_oe & (~io_3_force_input)),.reg_val(reg_3));
+   
+   // Upper 16 bits are mask for lower 16
+   always @(posedge clock)
+     if(serial_strobe)
+       case(serial_addr)
+	 `FR_OE_0 : io_0_oe
+	   <= #1 (io_0_oe & ~serial_data[31:16]) | (serial_data[15:0] & serial_data[31:16] );
+	 `FR_OE_1 : io_1_oe
+	   <= #1 (io_1_oe & ~serial_data[31:16]) | (serial_data[15:0] & serial_data[31:16] );
+	 `FR_OE_2 : io_2_oe
+	   <= #1 (io_2_oe & ~serial_data[31:16]) | (serial_data[15:0] & serial_data[31:16] );
+	 `FR_OE_3 : io_3_oe
+	   <= #1 (io_3_oe & ~serial_data[31:16]) | (serial_data[15:0] & serial_data[31:16] );
+       endcase // case(serial_addr)
+
+endmodule // io_pins