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// This is a component of pluto_servo, a PWM servo driver and quadrature
// counter for emc2
// Copyright 2006 Jeff Epler <jepler@unpythonic.net>
//
// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
module main(clk, led, nConfig, epp_nReset, pport_data, nWrite, nWait, nDataStr,
nAddrStr, dout, din, step, dir);
parameter W=10;
parameter F=11;
parameter T=4;
input clk;
output led, nConfig;
inout [7:0] pport_data;
input nWrite;
output nWait;
input nDataStr, nAddrStr, epp_nReset;
input [15:0] din;
reg Spolarity;
reg[13:0] real_dout; output [13:0] dout = do_tristate ? 14'bZ : real_dout;
wire[3:0] real_step; output [3:0] step = do_tristate ? 4'bZ : real_step ^ {4{Spolarity}};
wire[3:0] real_dir; output [3:0] dir = do_tristate ? 4'bZ : real_dir;
wire [W+F-1:0] pos0, pos1, pos2, pos3;
reg [F:0] vel0, vel1, vel2, vel3;
reg [T-1:0] dirtime, steptime;
reg [1:0] tap;
reg [10:0] div2048;
wire stepcnt = ~|(div2048[5:0]);
always @(posedge clk) begin
div2048 <= div2048 + 1'd1;
end
wire do_enable_wdt, do_tristate;
wdt w(clk, do_enable_wdt, &div2048, do_tristate);
stepgen #(W,F,T) s0(clk, stepcnt, pos0, vel0, dirtime, steptime, real_step[0], real_dir[0], tap);
stepgen #(W,F,T) s1(clk, stepcnt, pos1, vel1, dirtime, steptime, real_step[1], real_dir[1], tap);
stepgen #(W,F,T) s2(clk, stepcnt, pos2, vel2, dirtime, steptime, real_step[2], real_dir[2], tap);
stepgen #(W,F,T) s3(clk, stepcnt, pos3, vel3, dirtime, steptime, real_step[3], real_dir[3], tap);
// EPP stuff
wire EPP_write = ~nWrite;
wire EPP_read = nWrite;
wire EPP_addr_strobe = ~nAddrStr;
wire EPP_data_strobe = ~nDataStr;
wire EPP_strobe = EPP_data_strobe | EPP_addr_strobe;
wire EPP_wait; assign nWait = ~EPP_wait;
wire [7:0] EPP_datain = pport_data;
wire [7:0] EPP_dataout; assign pport_data = EPP_dataout;
reg [4:0] EPP_strobe_reg;
always @(posedge clk) EPP_strobe_reg <= {EPP_strobe_reg[3:0], EPP_strobe};
wire EPP_strobe_edge1 = (EPP_strobe_reg[2:1]==2'b01);
// reg led;
assign EPP_wait = EPP_strobe_reg[4];
wire[15:0] EPP_dataword = {EPP_datain, lowbyte};
reg[4:0] addr_reg;
reg[7:0] lowbyte;
always @(posedge clk)
if(EPP_strobe_edge1 & EPP_write & EPP_addr_strobe) begin
addr_reg <= EPP_datain[4:0];
end
else if(EPP_strobe_edge1 & !EPP_addr_strobe) addr_reg <= addr_reg + 4'd1;
always @(posedge clk) begin
if(EPP_strobe_edge1 & EPP_write & EPP_data_strobe) begin
if(addr_reg[3:0] == 4'd1) vel0 <= EPP_dataword[F:0];
else if(addr_reg[3:0] == 4'd3) vel1 <= EPP_dataword[F:0];
else if(addr_reg[3:0] == 4'd5) vel2 <= EPP_dataword[F:0];
else if(addr_reg[3:0] == 4'd7) vel3 <= EPP_dataword[F:0];
else if(addr_reg[3:0] == 4'd9) begin
real_dout <= { EPP_datain[5:0], lowbyte };
end
else if(addr_reg[3:0] == 4'd11) begin
tap <= lowbyte[7:6];
steptime <= lowbyte[T-1:0];
Spolarity <= EPP_datain[7];
// EPP_datain[6] is do_enable_wdt
dirtime <= EPP_datain[T-1:0];
end
else lowbyte <= EPP_datain;
end
end
reg [31:0] data_buf;
always @(posedge clk) begin
if(EPP_strobe_edge1 & EPP_read && addr_reg[1:0] == 2'd0) begin
if(addr_reg[4:2] == 3'd0) data_buf <= pos0;
else if(addr_reg[4:2] == 3'd1) data_buf <= pos1;
else if(addr_reg[4:2] == 3'd2) data_buf <= pos2;
else if(addr_reg[4:2] == 3'd3) data_buf <= pos3;
else if(addr_reg[4:2] == 3'd4)
data_buf <= din;
end
end
// the addr_reg test looks funny because it is auto-incremented in an always
// block so "1" reads the low byte, "2 and "3" read middle bytes, and "0"
// reads the high byte I have a feeling that I'm doing this in the wrong way.
wire [7:0] data_reg = addr_reg[1:0] == 2'd1 ? data_buf[7:0] :
(addr_reg[1:0] == 2'd2 ? data_buf[15:8] :
(addr_reg[1:0] == 2'd3 ? data_buf[23:16] :
data_buf[31:24]));
wire [7:0] EPP_data_mux = data_reg;
assign EPP_dataout = (EPP_read & EPP_wait) ? EPP_data_mux : 8'hZZ;
// assign do_enable_wdt = EPP_strobe_edge1 & EPP_write & EPP_data_strobe & (addr_reg[3:0] == 4'd9) & EPP_datain[6];
// assign led = do_tristate ? 1'BZ : (real_step[0] ^ real_dir[0]);
assign led = do_tristate ? 1'bZ : (real_step[0] ^ real_dir[0]);
assign nConfig = epp_nReset; // 1'b1;
assign do_enable_wdt = EPP_strobe_edge1 & EPP_write & EPP_data_strobe & (addr_reg[3:0] == 4'd9) & EPP_datain[6];
endmodule
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