/////////////////////////////////////////////////////////////////////////                                                             ////////  OpenCores ATA/ATAPI-5 Host Controller                      ////////  PIO Timing Controller (common for all OCIDEC cores)        ////////                                                             ////////  Author: Richard Herveille                                  ////////          richard@asics.ws                                   ////////          www.asics.ws                                       ////////                                                             /////////////////////////////////////////////////////////////////////////////                                                             //////// Copyright (C) 2001, 2002 Richard Herveille                  ////////                          richard@asics.ws                   ////////                                                             //////// This source file may be used and distributed without        //////// restriction provided that this copyright statement is not   //////// removed from the file and that any derivative work contains //////// the original copyright notice and the associated disclaimer.////////                                                             ////////     THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY     //////// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED   //////// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS   //////// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR      //////// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,         //////// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES    //////// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE   //////// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR        //////// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF  //////// LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT  //////// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT  //////// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE         //////// POSSIBILITY OF SUCH DAMAGE.                                 ////////                                                             ///////////////////////////////////////////////////////////////////////////  CVS Log////  $Id: atahost_pio_tctrl.v,v 1.1 2002/02/18 14:26:46 rherveille Exp $////  $Date: 2002/02/18 14:26:46 $//  $Revision: 1.1 $//  $Author: rherveille $//  $Locker:  $//  $State: Exp $//// Change History://               Rev. 1.0 June 27th, 2001. Initial Verilog release//               Rev. 1.1 July  2nd, 2001. Fixed incomplete port list and some Verilog related issues.//               Rev. 1.2 July 11th, 2001. Changed 'igo' & 'hold_go' generation.////               $Log: atahost_pio_tctrl.v,v $//               Revision 1.1  2002/02/18 14:26:46  rherveille//               Initial Verilog HDL release////               Revision 1.2  2002/02/16 10:42:17  rherveille//               Added disclaimer//               Added CVS information//               Changed core for new internal counter libraries (synthesis fixes).//////// Timing	PIO mode transfers//--------------------------------------------// T0:	cycle time// T1:	address valid to DIOR-/DIOW-// T2:	DIOR-/DIOW- pulse width// T2i:	DIOR-/DIOW- recovery time// T3:	DIOW- data setup// T4:	DIOW- data hold// T5:	DIOR- data setup// T6:	DIOR- data hold// T9:	address hold from DIOR-/DIOW- negated// Trd:	Read data valid to IORDY asserted// Ta:	IORDY setup time// Tb:	IORDY pulse width//// Transfer sequence//--------------------------------// 1)	set address (DA, CS0-, CS1-)// 2)	wait for T1// 3)	assert DIOR-/DIOW-//	   when write action present Data (timing spec. T3 always honored), enable output enable-signal// 4)	wait for T2// 5)	check IORDY//	   when not IORDY goto 5// 	  when IORDY negate DIOW-/DIOR-, latch data (if read action)//    when write, hold data for T4, disable output-enable signal// 6)	wait end_of_cycle_time. This is T2i or T9 or (T0-T1-T2) whichever takes the longest// 7)	start new cycle`include "timescale.v"module atahost_pio_tctrl(clk, nReset, rst, IORDY_en, T1, T2, T4, Teoc, go, we, oe, done, dstrb, DIOR, DIOW, IORDY);	// parameter declarations	parameter TWIDTH = 8;	parameter PIO_MODE0_T1   =  6;             // 70ns	parameter PIO_MODE0_T2   = 28;             // 290ns	parameter PIO_MODE0_T4   =  2;             // 30ns	parameter PIO_MODE0_Teoc = 23;             // 240ns		// inputs & outputs	input clk; // master clock	input nReset; // asynchronous active low reset	input rst; // synchronous active high reset		// timing & control register settings	input IORDY_en;          // use IORDY (or not)	input [TWIDTH-1:0] T1;   // T1 time (in clk-ticks)	input [TWIDTH-1:0] T2;   // T1 time (in clk-ticks)	input [TWIDTH-1:0] T4;   // T1 time (in clk-ticks)	input [TWIDTH-1:0] Teoc; // T1 time (in clk-ticks)	// control signals	input go; // PIO controller selected (strobe signal)	input we; // write enable signal. 1'b0 == read, 1'b1 == write	// return signals	output oe; // output enable signal	reg oe;	output done; // finished cycle	output dstrb; // data strobe, latch data (during read)	reg dstrb;	// ata signals	output DIOR; // IOread signal, active high	reg DIOR;	output DIOW; // IOwrite signal, active high	reg DIOW;	input  IORDY; // IOrDY signal	//	// constant declarations	//	// PIO mode 0 settings (@100MHz clock)	wire [TWIDTH-1:0] T1_m0   = PIO_MODE0_T1;	wire [TWIDTH-1:0] T2_m0   = PIO_MODE0_T2;	wire [TWIDTH-1:0] T4_m0   = PIO_MODE0_T4;	wire [TWIDTH-1:0] Teoc_m0 = PIO_MODE0_Teoc;	//	// variable declaration	//	reg busy, hold_go;	wire igo;	wire T1done, T2done, T4done, Teoc_done, IORDY_done;	reg hT2done;	//	// module body	//	// generate internal go strobe	// strecht go until ready for new cycle	always@(posedge clk or negedge nReset)		if (~nReset)			begin				busy    <= #1 1'b0;				hold_go <= #1 1'b0;			end		else if (rst)			begin				busy    <= #1 1'b0;				hold_go <= #1 1'b0;			end		else			begin				busy    <= #1 (igo | busy) & !Teoc_done;				hold_go <= #1 (go | (hold_go & busy)) & !igo;			end	assign igo = (go | hold_go) & !busy;	// 1)	hookup T1 counter	ro_cnt #(TWIDTH, 1'b0, PIO_MODE0_T1)		t1_cnt(			.clk(clk),			.rst(rst),			.nReset(nReset),			.cnt_en(1'b1),			.go(igo),			.d(T1),			.q(),			.done(T1done)		);	// 2)	set (and reset) DIOR-/DIOW-, set output-enable when writing to device	always@(posedge clk or negedge nReset)		if (~nReset)			begin				DIOR <= #1 1'b0;				DIOW <= #1 1'b0;				oe   <= #1 1'b0;			end		else if (rst)			begin				DIOR <= #1 1'b0;				DIOW <= #1 1'b0;				oe   <= #1 1'b0;			end		else			begin				DIOR <= #1 (!we & T1done) | (DIOR & !IORDY_done);				DIOW <= #1 ( we & T1done) | (DIOW & !IORDY_done);				oe   <= #1 ( (we & igo) | oe) & !T4done;           // negate oe when t4-done			end	// 3)	hookup T2 counter	ro_cnt #(TWIDTH, 1'b0, PIO_MODE0_T2)		t2_cnt(			.clk(clk),			.rst(rst),			.nReset(nReset),			.cnt_en(1'b1),			.go(T1done),			.d(T2),			.q(),			.done(T2done)		);	// 4)	check IORDY (if used), generate release_DIOR-/DIOW- signal (ie negate DIOR-/DIOW-)	// hold T2done	always@(posedge clk or negedge nReset)		if (~nReset)			hT2done <= #1 1'b0;		else if (rst)			hT2done <= #1 1'b0;		else			hT2done <= #1 (T2done | hT2done) & !IORDY_done;	assign IORDY_done = (T2done | hT2done) & (IORDY | !IORDY_en);	// generate datastrobe, capture data at rising DIOR- edge	always@(posedge clk)		dstrb <= #1 IORDY_done;	// hookup data hold counter	ro_cnt #(TWIDTH, 1'b0, PIO_MODE0_T4)		dhold_cnt(			.clk(clk),			.rst(rst),			.nReset(nReset),			.cnt_en(1'b1),			.go(IORDY_done),			.d(T4),			.q(),			.done(T4done)		);	assign done = T4done; // placing done here provides the fastest return possible,                         // while still guaranteeing data and address hold-times	// 5)	hookup end_of_cycle counter	ro_cnt #(TWIDTH, 1'b0, PIO_MODE0_Teoc)		eoc_cnt(			.clk(clk),			.rst(rst),			.nReset(nReset),			.cnt_en(1'b1),			.go(IORDY_done),			.d(Teoc),			.q(),			.done(Teoc_done)		);endmodule