///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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//
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//
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// Filename: llqspi.v
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// Filename: llqspi.v
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//
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//
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// Project: Wishbone Controlled Quad SPI Flash Controller
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// Project: Wishbone Controlled Quad SPI Flash Controller
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//
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//
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// Purpose: Reads/writes a word (user selectable number of bytes) of data
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// Purpose: Reads/writes a word (user selectable number of bytes) of data
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// to/from a Quad SPI port. The port is understood to be
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// to/from a Quad SPI port. The port is understood to be
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// a normal SPI port unless the driver requests four bit mode.
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// a normal SPI port unless the driver requests four bit mode.
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// When not in use, unlike our previous SPI work, no bits will
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// When not in use, unlike our previous SPI work, no bits will
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// toggle.
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// toggle.
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//
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//
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// Creator: Dan Gisselquist
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// Creator: Dan Gisselquist
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// Gisselquist Tecnology, LLC
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// Gisselquist Tecnology, LLC
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//
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//
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///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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//
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//
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// Copyright (C) 2015, Gisselquist Technology, LLC
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// Copyright (C) 2015, Gisselquist Technology, LLC
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//
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//
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// This program is free software (firmware): you can redistribute it and/or
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// This program is free software (firmware): you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as published
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// modify it under the terms of the GNU General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or (at
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// by the Free Software Foundation, either version 3 of the License, or (at
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// your option) any later version.
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// your option) any later version.
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//
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
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// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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// for more details.
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//
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//
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// You should have received a copy of the GNU General Public License along
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// You should have received a copy of the GNU General Public License along
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// with this program. (It's in the $(ROOT)/doc directory, run make with no
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// with this program. (It's in the $(ROOT)/doc directory, run make with no
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// target there if the PDF file isn't present.) If not, see
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// target there if the PDF file isn't present.) If not, see
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// <http://www.gnu.org/licenses/> for a copy.
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// <http://www.gnu.org/licenses/> for a copy.
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//
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//
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// License: GPL, v3, as defined and found on www.gnu.org,
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// License: GPL, v3, as defined and found on www.gnu.org,
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// http://www.gnu.org/licenses/gpl.html
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// http://www.gnu.org/licenses/gpl.html
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//
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//
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//
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//
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///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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`define QSPI_IDLE 3'h0
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`define QSPI_IDLE 3'h0
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`define QSPI_START 3'h1
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`define QSPI_START 3'h1
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`define QSPI_BITS 3'h2
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`define QSPI_BITS 3'h2
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`define QSPI_READY 3'h3
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`define QSPI_READY 3'h3
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`define QSPI_HOLDING 3'h4
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`define QSPI_HOLDING 3'h4
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`define QSPI_STOP 3'h5
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`define QSPI_STOP 3'h5
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`define QSPI_STOP_B 3'h6
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`define QSPI_STOP_B 3'h6
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// Modes
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// Modes
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`define QSPI_MOD_SPI 2'b00
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`define QSPI_MOD_SPI 2'b00
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`define QSPI_MOD_QOUT 2'b10
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`define QSPI_MOD_QOUT 2'b10
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`define QSPI_MOD_QIN 2'b11
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`define QSPI_MOD_QIN 2'b11
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module llqspi(i_clk,
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module llqspi(i_clk,
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// Module interface
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// Module interface
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i_wr, i_hold, i_word, i_len, i_spd, i_dir,
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i_wr, i_hold, i_word, i_len, i_spd, i_dir,
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o_word, o_valid, o_busy,
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o_word, o_valid, o_busy,
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// QSPI interface
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// QSPI interface
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o_sck, o_cs_n, o_mod, o_dat, i_dat);
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o_sck, o_cs_n, o_mod, o_dat, i_dat);
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input i_clk;
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input i_clk;
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// Chip interface
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// Chip interface
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// Can send info
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// Can send info
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// i_dir = 1, i_spd = 0, i_hold = 0, i_wr = 1,
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// i_dir = 1, i_spd = 0, i_hold = 0, i_wr = 1,
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// i_word = { 1'b0, 32'info to send },
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// i_word = { 1'b0, 32'info to send },
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// i_len = # of bytes in word-1
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// i_len = # of bytes in word-1
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input i_wr, i_hold;
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input i_wr, i_hold;
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input [31:0] i_word;
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input [31:0] i_word;
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input [1:0] i_len; // 0=>8bits, 1=>16 bits, 2=>24 bits, 3=>32 bits
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input [1:0] i_len; // 0=>8bits, 1=>16 bits, 2=>24 bits, 3=>32 bits
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input i_spd; // 0 -> normal QPI, 1 -> QSPI
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input i_spd; // 0 -> normal QPI, 1 -> QSPI
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input i_dir; // 0 -> read, 1 -> write to SPI
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input i_dir; // 0 -> read, 1 -> write to SPI
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output reg [31:0] o_word;
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output reg [31:0] o_word;
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output reg o_valid, o_busy;
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output reg o_valid, o_busy;
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// Interface with the QSPI lines
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// Interface with the QSPI lines
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output reg o_sck;
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output reg o_sck;
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output reg o_cs_n;
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output reg o_cs_n;
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output reg [1:0] o_mod;
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output reg [1:0] o_mod;
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output reg [3:0] o_dat;
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output reg [3:0] o_dat;
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input [3:0] i_dat;
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input [3:0] i_dat;
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// output wire [22:0] o_dbg;
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// assign o_dbg = { state, spi_len,
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// o_busy, o_valid, o_cs_n, o_sck, o_mod, o_dat, i_dat };
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// Timing:
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// Timing:
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//
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//
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// Tick Clk BSY/WR CS_n BIT/MO STATE
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// Tick Clk BSY/WR CS_n BIT/MO STATE
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// 0 1 0/0 1 -
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// 0 1 0/0 1 -
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// 1 1 0/1 1 -
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// 1 1 0/1 1 -
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// 2 1 1/0 0 - QSPI_START
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// 2 1 1/0 0 - QSPI_START
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// 3 0 1/0 0 - QSPI_START
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// 3 0 1/0 0 - QSPI_START
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// 4 0 1/0 0 0 QSPI_BITS
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// 4 0 1/0 0 0 QSPI_BITS
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// 5 1 1/0 0 0 QSPI_BITS
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// 5 1 1/0 0 0 QSPI_BITS
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// 6 0 1/0 0 1 QSPI_BITS
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// 6 0 1/0 0 1 QSPI_BITS
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// 7 1 1/0 0 1 QSPI_BITS
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// 7 1 1/0 0 1 QSPI_BITS
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// 8 0 1/0 0 2 QSPI_BITS
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// 8 0 1/0 0 2 QSPI_BITS
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// 9 1 1/0 0 2 QSPI_BITS
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// 9 1 1/0 0 2 QSPI_BITS
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// 10 0 1/0 0 3 QSPI_BITS
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// 10 0 1/0 0 3 QSPI_BITS
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// 11 1 1/0 0 3 QSPI_BITS
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// 11 1 1/0 0 3 QSPI_BITS
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// 12 0 1/0 0 4 QSPI_BITS
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// 12 0 1/0 0 4 QSPI_BITS
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// 13 1 1/0 0 4 QSPI_BITS
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// 13 1 1/0 0 4 QSPI_BITS
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// 14 0 1/0 0 5 QSPI_BITS
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// 14 0 1/0 0 5 QSPI_BITS
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// 15 1 1/0 0 5 QSPI_BITS
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// 15 1 1/0 0 5 QSPI_BITS
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// 16 0 1/0 0 6 QSPI_BITS
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// 16 0 1/0 0 6 QSPI_BITS
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// 17 1 1/1 0 6 QSPI_BITS
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// 17 1 1/1 0 6 QSPI_BITS
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// 18 0 1/1 0 7 QSPI_READY
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// 18 0 1/1 0 7 QSPI_READY
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// 19 1 0/1 0 7 QSPI_READY
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// 19 1 0/1 0 7 QSPI_READY
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// 20 0 1/0/V 0 8 QSPI_BITS
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// 20 0 1/0/V 0 8 QSPI_BITS
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// 21 1 1/0 0 8 QSPI_BITS
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// 21 1 1/0 0 8 QSPI_BITS
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// 22 0 1/0 0 9 QSPI_BITS
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// 22 0 1/0 0 9 QSPI_BITS
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// 23 1 1/0 0 9 QSPI_BITS
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// 23 1 1/0 0 9 QSPI_BITS
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// 24 0 1/0 0 10 QSPI_BITS
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// 24 0 1/0 0 10 QSPI_BITS
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// 25 1 1/0 0 10 QSPI_BITS
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// 25 1 1/0 0 10 QSPI_BITS
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// 26 0 1/0 0 11 QSPI_BITS
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// 26 0 1/0 0 11 QSPI_BITS
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// 27 1 1/0 0 11 QSPI_BITS
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// 27 1 1/0 0 11 QSPI_BITS
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// 28 0 1/0 0 12 QSPI_BITS
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// 28 0 1/0 0 12 QSPI_BITS
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// 29 1 1/0 0 12 QSPI_BITS
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// 29 1 1/0 0 12 QSPI_BITS
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// 30 0 1/0 0 13 QSPI_BITS
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// 30 0 1/0 0 13 QSPI_BITS
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// 31 1 1/0 0 13 QSPI_BITS
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// 31 1 1/0 0 13 QSPI_BITS
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// 32 0 1/0 0 14 QSPI_BITS
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// 32 0 1/0 0 14 QSPI_BITS
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// 33 1 1/0 0 14 QSPI_BITS
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// 33 1 1/0 0 14 QSPI_BITS
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// 34 0 1/0 0 15 QSPI_READY
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// 34 0 1/0 0 15 QSPI_READY
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// 35 1 1/0 0 15 QSPI_READY
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// 35 1 1/0 0 15 QSPI_READY
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// 36 1 1/0/V 0 - QSPI_STOP
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// 36 1 1/0/V 0 - QSPI_STOP
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// 37 1 1/0 0 - QSPI_STOPB
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// 37 1 1/0 0 - QSPI_STOPB
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// 38 1 1/0 1 - QSPI_IDLE
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// 38 1 1/0 1 - QSPI_IDLE
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// 39 1 0/0 1 -
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// 39 1 0/0 1 -
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// Now, let's switch from single bit to quad mode
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// Now, let's switch from single bit to quad mode
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// 40 1 0/0 1 - QSPI_IDLE
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// 40 1 0/0 1 - QSPI_IDLE
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// 41 1 0/1 1 - QSPI_IDLE
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// 41 1 0/1 1 - QSPI_IDLE
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// 42 1 1/0 0 - QSPI_START
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// 42 1 1/0 0 - QSPI_START
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// 43 0 1/0 0 - QSPI_START
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// 43 0 1/0 0 - QSPI_START
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// 44 0 1/0 0 0 QSPI_BITS
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// 44 0 1/0 0 0 QSPI_BITS
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// 45 1 1/0 0 0 QSPI_BITS
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// 45 1 1/0 0 0 QSPI_BITS
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// 46 0 1/0 0 1 QSPI_BITS
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// 46 0 1/0 0 1 QSPI_BITS
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// 47 1 1/0 0 1 QSPI_BITS
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// 47 1 1/0 0 1 QSPI_BITS
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// 48 0 1/0 0 2 QSPI_BITS
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// 48 0 1/0 0 2 QSPI_BITS
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// 49 1 1/0 0 2 QSPI_BITS
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// 49 1 1/0 0 2 QSPI_BITS
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// 50 0 1/0 0 3 QSPI_BITS
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// 50 0 1/0 0 3 QSPI_BITS
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// 51 1 1/0 0 3 QSPI_BITS
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// 51 1 1/0 0 3 QSPI_BITS
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// 52 0 1/0 0 4 QSPI_BITS
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// 52 0 1/0 0 4 QSPI_BITS
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// 53 1 1/0 0 4 QSPI_BITS
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// 53 1 1/0 0 4 QSPI_BITS
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// 54 0 1/0 0 5 QSPI_BITS
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// 54 0 1/0 0 5 QSPI_BITS
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// 55 1 1/0 0 5 QSPI_BITS
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// 55 1 1/0 0 5 QSPI_BITS
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// 56 0 1/0 0 6 QSPI_BITS
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// 56 0 1/0 0 6 QSPI_BITS
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// 57 1 1/1/QR 0 6 QSPI_BITS
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// 57 1 1/1/QR 0 6 QSPI_BITS
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// 58 0 1/1/QR 0 7 QSPI_READY
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// 58 0 1/1/QR 0 7 QSPI_READY
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// 59 1 0/1/QR 0 7 QSPI_READY
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// 59 1 0/1/QR 0 7 QSPI_READY
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// 60 0 1/0/?/V 0 8-11 QSPI_BITS
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// 60 0 1/0/?/V 0 8-11 QSPI_BITS
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// 61 1 1/0/? 0 8-11 QSPI_BITS
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// 61 1 1/0/? 0 8-11 QSPI_BITS
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// 62 0 1/0/? 0 12-15 QSPI_BITS
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// 62 0 1/0/? 0 12-15 QSPI_BITS
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// 63 1 1/0/? 0 12-15 QSPI_BITS
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// 63 1 1/0/? 0 12-15 QSPI_BITS
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// 64 1 1/0/?/V 0 - QSPI_STOP
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// 64 1 1/0/?/V 0 - QSPI_STOP
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// 65 1 1/0/? 0 - QSPI_STOPB
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// 65 1 1/0/? 0 - QSPI_STOPB
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// 66 1 1/0/? 1 - QSPI_IDLE
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// 66 1 1/0/? 1 - QSPI_IDLE
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// 67 1 0/0 1 - QSPI_IDLE
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// 67 1 0/0 1 - QSPI_IDLE
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// Now let's try something entirely in Quad read mode, from the
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// Now let's try something entirely in Quad read mode, from the
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// beginning
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// beginning
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// 68 1 0/1/QR 1 - QSPI_IDLE
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// 68 1 0/1/QR 1 - QSPI_IDLE
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// 69 1 1/0 0 - QSPI_START
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// 69 1 1/0 0 - QSPI_START
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// 70 0 1/0 0 - QSPI_START
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// 70 0 1/0 0 - QSPI_START
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// 71 0 1/0 0 0-3 QSPI_BITS
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// 71 0 1/0 0 0-3 QSPI_BITS
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// 72 1 1/0 0 0-3 QSPI_BITS
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// 72 1 1/0 0 0-3 QSPI_BITS
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// 73 0 1/1/QR 0 4-7 QSPI_BITS
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// 73 0 1/1/QR 0 4-7 QSPI_BITS
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// 74 1 0/1/QR 0 4-7 QSPI_BITS
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// 74 1 0/1/QR 0 4-7 QSPI_BITS
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// 75 0 1/?/?/V 0 8-11 QSPI_BITS
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// 75 0 1/?/?/V 0 8-11 QSPI_BITS
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// 76 1 1/?/? 0 8-11 QSPI_BITS
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// 76 1 1/?/? 0 8-11 QSPI_BITS
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// 77 0 1/1/QR 0 12-15 QSPI_BITS
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// 77 0 1/1/QR 0 12-15 QSPI_BITS
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// 78 1 0/1/QR 0 12-15 QSPI_BITS
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// 78 1 0/1/QR 0 12-15 QSPI_BITS
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// 79 0 1/?/?/V 0 16-19 QSPI_BITS
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// 79 0 1/?/?/V 0 16-19 QSPI_BITS
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// 80 1 1/0 0 16-19 QSPI_BITS
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// 80 1 1/0 0 16-19 QSPI_BITS
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// 81 0 1/0 0 20-23 QSPI_BITS
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// 81 0 1/0 0 20-23 QSPI_BITS
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// 82 1 1/0 0 20-23 QSPI_BITS
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// 82 1 1/0 0 20-23 QSPI_BITS
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// 83 1 1/0/V 0 - QSPI_STOP
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// 83 1 1/0/V 0 - QSPI_STOP
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// 84 1 1/0 0 - QSPI_STOPB
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// 84 1 1/0 0 - QSPI_STOPB
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// 85 1 1/0 1 - QSPI_IDLE
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// 85 1 1/0 1 - QSPI_IDLE
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// 86 1 0/0 1 - QSPI_IDLE
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// 86 1 0/0 1 - QSPI_IDLE
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wire i_miso;
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wire i_miso;
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assign i_miso = i_dat[1];
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assign i_miso = i_dat[1];
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reg r_spd, r_dir;
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reg r_spd, r_dir;
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reg [5:0] spi_len;
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reg [5:0] spi_len;
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reg [31:0] r_word;
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reg [31:0] r_word;
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reg [30:0] r_input;
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reg [30:0] r_input;
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reg [2:0] state;
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reg [2:0] state;
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initial state = `QSPI_IDLE;
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initial state = `QSPI_IDLE;
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initial o_sck = 1'b1;
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initial o_sck = 1'b1;
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initial o_cs_n = 1'b1;
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initial o_cs_n = 1'b1;
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initial o_dat = 4'hd;
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initial o_dat = 4'hd;
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initial o_valid = 1'b0;
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initial o_valid = 1'b0;
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initial o_busy = 1'b0;
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initial o_busy = 1'b0;
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initial r_input = 31'h000;
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initial r_input = 31'h000;
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always @(posedge i_clk)
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always @(posedge i_clk)
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if ((state == `QSPI_IDLE)&&(o_sck))
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if ((state == `QSPI_IDLE)&&(o_sck))
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begin
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begin
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o_cs_n <= 1'b1;
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o_cs_n <= 1'b1;
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o_valid <= 1'b0;
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o_valid <= 1'b0;
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o_busy <= 1'b0;
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o_busy <= 1'b0;
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o_mod <= `QSPI_MOD_SPI;
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o_mod <= `QSPI_MOD_SPI;
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if (i_wr)
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if (i_wr)
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begin
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begin
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r_word <= i_word;
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r_word <= i_word;
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state <= `QSPI_START;
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state <= `QSPI_START;
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r_spd <= i_spd;
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r_spd <= i_spd;
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r_dir <= i_dir;
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r_dir <= i_dir;
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spi_len<= { 1'b0, i_len, 3'b000 } + 6'h8;
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spi_len<= { 1'b0, i_len, 3'b000 } + 6'h8;
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o_cs_n <= 1'b0;
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o_cs_n <= 1'b0;
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o_busy <= 1'b1;
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o_busy <= 1'b1;
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o_sck <= 1'b1;
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o_sck <= 1'b1;
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end
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end
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end else if (state == `QSPI_START)
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end else if (state == `QSPI_START)
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begin // We come in here with sck high, stay here 'til sck is low
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begin // We come in here with sck high, stay here 'til sck is low
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o_sck <= 1'b0;
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o_sck <= 1'b0;
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if (o_sck == 1'b0)
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if (o_sck == 1'b0)
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begin
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begin
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state <= `QSPI_BITS;
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state <= `QSPI_BITS;
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spi_len<= spi_len - ( (r_spd)? 6'h4 : 6'h1 );
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spi_len<= spi_len - ( (r_spd)? 6'h4 : 6'h1 );
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if (r_spd)
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if (r_spd)
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r_word <= { r_word[27:0], 4'h0 };
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r_word <= { r_word[27:0], 4'h0 };
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else
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else
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r_word <= { r_word[30:0], 1'b0 };
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r_word <= { r_word[30:0], 1'b0 };
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end
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end
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o_mod <= (r_spd) ? { 1'b1, r_dir } : `QSPI_MOD_SPI;
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o_mod <= (r_spd) ? { 1'b1, r_dir } : `QSPI_MOD_SPI;
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o_cs_n <= 1'b0;
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o_cs_n <= 1'b0;
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o_busy <= 1'b1;
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o_busy <= 1'b1;
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o_valid <= 1'b0;
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o_valid <= 1'b0;
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if (r_spd)
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if (r_spd)
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begin
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begin
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o_dat <= r_word[31:28];
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o_dat <= r_word[31:28];
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// r_word <= { r_word[27:0], 4'h0 };
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// r_word <= { r_word[27:0], 4'h0 };
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end else begin
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end else begin
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o_dat <= { 3'b110, r_word[31] };
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o_dat <= { 3'b110, r_word[31] };
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// r_word <= { r_word[30:0], 1'b0 };
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// r_word <= { r_word[30:0], 1'b0 };
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end
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end
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end else if (~o_sck)
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end else if (~o_sck)
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begin
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begin
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o_sck <= 1'b1;
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o_sck <= 1'b1;
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o_busy <= ((state != `QSPI_READY)||(~i_wr));
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o_busy <= ((state != `QSPI_READY)||(~i_wr));
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o_valid <= 1'b0;
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o_valid <= 1'b0;
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end else if (state == `QSPI_BITS)
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end else if (state == `QSPI_BITS)
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begin
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begin
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// Should enter into here with at least a spi_len
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// Should enter into here with at least a spi_len
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// of one, perhaps more
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// of one, perhaps more
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o_sck <= 1'b0;
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o_sck <= 1'b0;
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o_busy <= 1'b1;
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o_busy <= 1'b1;
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if (r_spd)
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if (r_spd)
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begin
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begin
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o_dat <= r_word[31:28];
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o_dat <= r_word[31:28];
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r_word <= { r_word[27:0], 4'h0 };
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r_word <= { r_word[27:0], 4'h0 };
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spi_len <= spi_len - 6'h4;
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spi_len <= spi_len - 6'h4;
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if (spi_len == 6'h4)
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if (spi_len == 6'h4)
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state <= `QSPI_READY;
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state <= `QSPI_READY;
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end else begin
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end else begin
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o_dat <= { 3'b110, r_word[31] };
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o_dat <= { 3'b110, r_word[31] };
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r_word <= { r_word[30:0], 1'b0 };
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r_word <= { r_word[30:0], 1'b0 };
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spi_len <= spi_len - 6'h1;
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spi_len <= spi_len - 6'h1;
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if (spi_len == 6'h1)
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if (spi_len == 6'h1)
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state <= `QSPI_READY;
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state <= `QSPI_READY;
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end
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end
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|
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o_valid <= 1'b0;
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o_valid <= 1'b0;
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if (~o_mod[1])
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if (~o_mod[1])
|
r_input <= { r_input[29:0], i_miso };
|
r_input <= { r_input[29:0], i_miso };
|
else if (o_mod[1])
|
else if (o_mod[1])
|
r_input <= { r_input[26:0], i_dat };
|
r_input <= { r_input[26:0], i_dat };
|
end else if (state == `QSPI_READY)
|
end else if (state == `QSPI_READY)
|
begin
|
begin
|
o_valid <= 1'b0;
|
o_valid <= 1'b0;
|
o_cs_n <= 1'b0;
|
o_cs_n <= 1'b0;
|
o_busy <= 1'b1;
|
o_busy <= 1'b1;
|
// This is the state on the last clock (both low and
|
// This is the state on the last clock (both low and
|
// high clocks) of the data. Data is valid during
|
// high clocks) of the data. Data is valid during
|
// this state. Here we chose to either STOP or
|
// this state. Here we chose to either STOP or
|
// continue and transmit more.
|
// continue and transmit more.
|
o_sck <= (i_hold); // No clocks while holding
|
o_sck <= (i_hold); // No clocks while holding
|
if((~o_busy)&&(i_wr))// Acknowledge a new request
|
if((~o_busy)&&(i_wr))// Acknowledge a new request
|
begin
|
begin
|
state <= `QSPI_BITS;
|
state <= `QSPI_BITS;
|
o_busy <= 1'b1;
|
o_busy <= 1'b1;
|
o_sck <= 1'b0;
|
o_sck <= 1'b0;
|
|
|
// Read the new request off the bus
|
// Read the new request off the bus
|
r_spd <= i_spd;
|
r_spd <= i_spd;
|
r_dir <= i_dir;
|
r_dir <= i_dir;
|
// Set up the first bits on the bus
|
// Set up the first bits on the bus
|
o_mod <= (i_spd) ? { 1'b1, i_dir } : `QSPI_MOD_SPI;
|
o_mod <= (i_spd) ? { 1'b1, i_dir } : `QSPI_MOD_SPI;
|
if (i_spd)
|
if (i_spd)
|
begin
|
begin
|
o_dat <= i_word[31:28];
|
o_dat <= i_word[31:28];
|
r_word <= { i_word[27:0], 4'h0 };
|
r_word <= { i_word[27:0], 4'h0 };
|
// spi_len <= spi_len - 4;
|
// spi_len <= spi_len - 4;
|
spi_len<= { 1'b0, i_len, 3'b000 } + 6'h8
|
spi_len<= { 1'b0, i_len, 3'b000 } + 6'h8
|
- 6'h4;
|
- 6'h4;
|
end else begin
|
end else begin
|
o_dat <= { 3'b110, i_word[31] };
|
o_dat <= { 3'b110, i_word[31] };
|
r_word <= { i_word[30:0], 1'b0 };
|
r_word <= { i_word[30:0], 1'b0 };
|
spi_len<= { 1'b0, i_len, 3'b000 } + 6'h8
|
spi_len<= { 1'b0, i_len, 3'b000 } + 6'h8
|
- 6'h1;
|
- 6'h1;
|
end
|
end
|
|
|
// Read a bit upon any transition
|
// Read a bit upon any transition
|
o_valid <= 1'b1;
|
o_valid <= 1'b1;
|
if (~o_mod[1])
|
if (~o_mod[1])
|
begin
|
begin
|
r_input <= { r_input[29:0], i_miso };
|
r_input <= { r_input[29:0], i_miso };
|
o_word <= { r_input[30:0], i_miso };
|
o_word <= { r_input[30:0], i_miso };
|
end else if (o_mod[1])
|
end else if (o_mod[1])
|
begin
|
begin
|
r_input <= { r_input[26:0], i_dat };
|
r_input <= { r_input[26:0], i_dat };
|
o_word <= { r_input[27:0], i_dat };
|
o_word <= { r_input[27:0], i_dat };
|
end
|
end
|
end else begin
|
end else begin
|
o_sck <= 1'b1;
|
o_sck <= 1'b1;
|
state <= (i_hold)?`QSPI_HOLDING : `QSPI_STOP;
|
state <= (i_hold)?`QSPI_HOLDING : `QSPI_STOP;
|
o_busy <= (~i_hold);
|
o_busy <= (~i_hold);
|
|
|
// Read a bit upon any transition
|
// Read a bit upon any transition
|
o_valid <= 1'b1;
|
o_valid <= 1'b1;
|
if (~o_mod[1])
|
if (~o_mod[1])
|
begin
|
begin
|
r_input <= { r_input[29:0], i_miso };
|
r_input <= { r_input[29:0], i_miso };
|
o_word <= { r_input[30:0], i_miso };
|
o_word <= { r_input[30:0], i_miso };
|
end else if (o_mod[1])
|
end else if (o_mod[1])
|
begin
|
begin
|
r_input <= { r_input[26:0], i_dat };
|
r_input <= { r_input[26:0], i_dat };
|
o_word <= { r_input[27:0], i_dat };
|
o_word <= { r_input[27:0], i_dat };
|
end
|
end
|
end
|
end
|
end else if (state == `QSPI_HOLDING)
|
end else if (state == `QSPI_HOLDING)
|
begin
|
begin
|
// We need this state so that the o_valid signal
|
// We need this state so that the o_valid signal
|
// can get strobed with our last result. Otherwise
|
// can get strobed with our last result. Otherwise
|
// we could just sit in READY waiting for a new command.
|
// we could just sit in READY waiting for a new command.
|
//
|
//
|
// Incidentally, the change producing this state was
|
// Incidentally, the change producing this state was
|
// the result of a nasty race condition. See the
|
// the result of a nasty race condition. See the
|
// commends in wbqspiflash for more details.
|
// commends in wbqspiflash for more details.
|
//
|
//
|
o_valid <= 1'b0;
|
o_valid <= 1'b0;
|
o_cs_n <= 1'b0;
|
o_cs_n <= 1'b0;
|
o_busy <= 1'b0;
|
o_busy <= 1'b0;
|
if((~o_busy)&&(i_wr))// Acknowledge a new request
|
if((~o_busy)&&(i_wr))// Acknowledge a new request
|
begin
|
begin
|
state <= `QSPI_BITS;
|
state <= `QSPI_BITS;
|
o_busy <= 1'b1;
|
o_busy <= 1'b1;
|
o_sck <= 1'b0;
|
o_sck <= 1'b0;
|
|
|
// Read the new request off the bus
|
// Read the new request off the bus
|
r_spd <= i_spd;
|
r_spd <= i_spd;
|
r_dir <= i_dir;
|
r_dir <= i_dir;
|
// Set up the first bits on the bus
|
// Set up the first bits on the bus
|
o_mod<=(i_spd)?{ 1'b1, i_dir } : `QSPI_MOD_SPI;
|
o_mod<=(i_spd)?{ 1'b1, i_dir } : `QSPI_MOD_SPI;
|
if (i_spd)
|
if (i_spd)
|
begin
|
begin
|
o_dat <= i_word[31:28];
|
o_dat <= i_word[31:28];
|
r_word <= { i_word[27:0], 4'h0 };
|
r_word <= { i_word[27:0], 4'h0 };
|
spi_len<= { 1'b0, i_len, 3'b100 };
|
spi_len<= { 1'b0, i_len, 3'b100 };
|
end else begin
|
end else begin
|
o_dat <= { 3'b110, i_word[31] };
|
o_dat <= { 3'b110, i_word[31] };
|
r_word <= { i_word[30:0], 1'b0 };
|
r_word <= { i_word[30:0], 1'b0 };
|
spi_len<= { 1'b0, i_len, 3'b111 };
|
spi_len<= { 1'b0, i_len, 3'b111 };
|
end
|
end
|
end else begin
|
end else begin
|
o_sck <= 1'b1;
|
o_sck <= 1'b1;
|
state <= (i_hold)?`QSPI_HOLDING : `QSPI_STOP;
|
state <= (i_hold)?`QSPI_HOLDING : `QSPI_STOP;
|
o_busy <= (~i_hold);
|
o_busy <= (~i_hold);
|
end
|
end
|
end else if (state == `QSPI_STOP)
|
end else if (state == `QSPI_STOP)
|
begin
|
begin
|
o_sck <= 1'b1; // Stop the clock
|
o_sck <= 1'b1; // Stop the clock
|
o_valid <= 1'b0; // Output may have just been valid, but no more
|
o_valid <= 1'b0; // Output may have just been valid, but no more
|
o_busy <= 1'b1; // Still busy till port is clear
|
o_busy <= 1'b1; // Still busy till port is clear
|
state <= `QSPI_STOP_B;
|
state <= `QSPI_STOP_B;
|
o_mod <= `QSPI_MOD_SPI;
|
o_mod <= `QSPI_MOD_SPI;
|
end else if (state == `QSPI_STOP_B)
|
end else if (state == `QSPI_STOP_B)
|
begin
|
begin
|
o_cs_n <= 1'b1;
|
o_cs_n <= 1'b1;
|
o_sck <= 1'b1;
|
o_sck <= 1'b1;
|
// Do I need this????
|
// Do I need this????
|
// spi_len <= 3; // Minimum CS high time before next cmd
|
// spi_len <= 3; // Minimum CS high time before next cmd
|
state <= `QSPI_IDLE;
|
state <= `QSPI_IDLE;
|
o_valid <= 1'b0;
|
o_valid <= 1'b0;
|
o_busy <= 1'b1;
|
o_busy <= 1'b1;
|
o_mod <= `QSPI_MOD_SPI;
|
o_mod <= `QSPI_MOD_SPI;
|
end else begin // Invalid states, should never get here
|
end else begin // Invalid states, should never get here
|
state <= `QSPI_STOP;
|
state <= `QSPI_STOP;
|
o_valid <= 1'b0;
|
o_valid <= 1'b0;
|
o_busy <= 1'b1;
|
o_busy <= 1'b1;
|
o_cs_n <= 1'b1;
|
o_cs_n <= 1'b1;
|
o_sck <= 1'b1;
|
o_sck <= 1'b1;
|
o_mod <= `QSPI_MOD_SPI;
|
o_mod <= `QSPI_MOD_SPI;
|
o_dat <= 4'hd;
|
o_dat <= 4'hd;
|
end
|
end
|
|
|
endmodule
|
endmodule
|
|
|
|
|
