| 1 |
5 |
dgisselq |
///////////////////////////////////////////////////////////////////////////
|
| 2 |
|
|
//
|
| 3 |
|
|
// Filename: rtcdate.v
|
| 4 |
|
|
//
|
| 5 |
|
|
// Project: A Wishbone Controlled Real--time Clock Core
|
| 6 |
|
|
//
|
| 7 |
|
|
// Purpose:
|
| 8 |
|
|
// This core provides a real-time date function that can be coupled with
|
| 9 |
|
|
// a real-time clock. The date provided is in Binary Coded Decimal (bcd)
|
| 10 |
|
|
// form, and available for reading and writing over the Wishbone Bus.
|
| 11 |
|
|
//
|
| 12 |
|
|
// WARNING: Race conditions exist when updating the date across the Wishbone
|
| 13 |
|
|
// bus at or near midnight. (This should be obvious, but it bears
|
| 14 |
|
|
// stating.) Specifically, if the update command shows up at the same
|
| 15 |
|
|
// clock as the ppd clock, then the ppd clock will be ignored and the
|
| 16 |
|
|
// new date will be the date of the day following midnight. However,
|
| 17 |
|
|
// if the update command shows up one clock before the ppd, then the date
|
| 18 |
|
|
// may be updated, but may have problems dealing with the last day of the
|
| 19 |
|
|
// month or year. To avoid race conditions, update the date sometime
|
| 20 |
|
|
// after the stroke of midnight and before 5 clocks before the next
|
| 21 |
|
|
// midnight. If you are concerned that you might hit a race condition,
|
| 22 |
|
|
// just read the clock again (5+ clocks later) to make certain you set
|
| 23 |
|
|
// it correctly.
|
| 24 |
|
|
//
|
| 25 |
|
|
//
|
| 26 |
|
|
// Creator: Dan Gisselquist, Ph.D.
|
| 27 |
|
|
// Gisselquist Tecnology, LLC
|
| 28 |
|
|
//
|
| 29 |
|
|
///////////////////////////////////////////////////////////////////////////
|
| 30 |
|
|
//
|
| 31 |
|
|
// Copyright (C) 2015, Gisselquist Technology, LLC
|
| 32 |
|
|
//
|
| 33 |
|
|
// This program is free software (firmware): you can redistribute it and/or
|
| 34 |
|
|
// modify it under the terms of the GNU General Public License as published
|
| 35 |
|
|
// by the Free Software Foundation, either version 3 of the License, or (at
|
| 36 |
|
|
// your option) any later version.
|
| 37 |
|
|
//
|
| 38 |
|
|
// This program is distributed in the hope that it will be useful, but WITHOUT
|
| 39 |
|
|
// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
|
| 40 |
|
|
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
| 41 |
|
|
// for more details.
|
| 42 |
|
|
//
|
| 43 |
|
|
// You should have received a copy of the GNU General Public License along
|
| 44 |
|
|
// with this program. (It's in the $(ROOT)/doc directory. Run make with no
|
| 45 |
|
|
// target there if the PDF file isn't present.) If not, see
|
| 46 |
|
|
// <http://www.gnu.org/licenses/> for a copy.
|
| 47 |
|
|
//
|
| 48 |
|
|
// License: GPL, v3, as defined and found on www.gnu.org,
|
| 49 |
|
|
// http://www.gnu.org/licenses/gpl.html
|
| 50 |
|
|
//
|
| 51 |
|
|
//
|
| 52 |
|
|
///////////////////////////////////////////////////////////////////////////
|
| 53 |
|
|
module rtcdate(i_clk, i_ppd, i_wb_cyc, i_wb_stb, i_wb_we, i_wb_data,
|
| 54 |
|
|
o_wb_ack, o_wb_stall, o_wb_data);
|
| 55 |
|
|
input i_clk;
|
| 56 |
|
|
// A one part per day signal, i.e. basically a clock enable line that
|
| 57 |
|
|
// controls when the beginning of the day happens. This line should
|
| 58 |
|
|
// be high on the very last second of any day in order for the rtcdate
|
| 59 |
|
|
// module to always have the right date.
|
| 60 |
|
|
input i_ppd;
|
| 61 |
|
|
// Wishbone inputs
|
| 62 |
|
|
input i_wb_cyc, i_wb_stb, i_wb_we;
|
| 63 |
|
|
input [31:0] i_wb_data;
|
| 64 |
|
|
// Wishbone outputs
|
| 65 |
|
|
output reg o_wb_ack;
|
| 66 |
|
|
output wire o_wb_stall;
|
| 67 |
|
|
output wire [31:0] o_wb_data;
|
| 68 |
|
|
|
| 69 |
|
|
|
| 70 |
|
|
reg [5:0] r_day;
|
| 71 |
|
|
reg [4:0] r_mon;
|
| 72 |
|
|
reg [13:0] r_year;
|
| 73 |
|
|
|
| 74 |
|
|
reg last_day_of_month, last_day_of_year, is_leap_year;
|
| 75 |
|
|
always @(posedge i_clk)
|
| 76 |
|
|
last_day_of_year <= (last_day_of_month) && (r_mon == 5'h12);
|
| 77 |
|
|
always @(posedge i_clk)
|
| 78 |
|
|
begin
|
| 79 |
|
|
case(r_mon)
|
| 80 |
|
|
5'h01: last_day_of_month <= (r_day >= 6'h31); // Jan
|
| 81 |
|
|
5'h02: last_day_of_month <= (r_day >= 6'h29)
|
| 82 |
|
|
||((~is_leap_year)&&(r_day == 6'h28));
|
| 83 |
|
|
5'h03: last_day_of_month <= (r_day >= 6'h31); // March
|
| 84 |
|
|
5'h04: last_day_of_month <= (r_day >= 6'h30); // April
|
| 85 |
|
|
5'h05: last_day_of_month <= (r_day >= 6'h31); // May
|
| 86 |
|
|
5'h06: last_day_of_month <= (r_day >= 6'h30); // June
|
| 87 |
|
|
5'h07: last_day_of_month <= (r_day >= 6'h31); // July
|
| 88 |
|
|
5'h08: last_day_of_month <= (r_day >= 6'h31); // August
|
| 89 |
|
|
5'h09: last_day_of_month <= (r_day >= 6'h30); // Sept
|
| 90 |
|
|
5'h10: last_day_of_month <= (r_day >= 6'h31); // October
|
| 91 |
|
|
5'h11: last_day_of_month <= (r_day >= 6'h30); // November
|
| 92 |
|
|
5'h12: last_day_of_month <= (r_day >= 6'h31); // December
|
| 93 |
|
|
default: last_day_of_month <= 1'b0;
|
| 94 |
|
|
endcase
|
| 95 |
|
|
end
|
| 96 |
|
|
|
| 97 |
|
|
reg year_divisible_by_four, century_year, four_century_year;
|
| 98 |
|
|
always @(posedge i_clk)
|
| 99 |
|
|
year_divisible_by_four<= ((~r_year[0])&&(r_year[4]==r_year[1]));
|
| 100 |
|
|
always @(posedge i_clk)
|
| 101 |
|
|
century_year <= (r_year[7:0] == 8'h00);
|
| 102 |
|
|
always @(posedge i_clk)
|
| 103 |
|
|
four_century_year <= ((~r_year[8])&&((r_year[12]==r_year[9])));
|
| 104 |
|
|
always @(posedge i_clk)
|
| 105 |
|
|
is_leap_year <= (year_divisible_by_four)&&((~century_year)
|
| 106 |
|
|
||((century_year)&&(four_century_year)));
|
| 107 |
|
|
|
| 108 |
|
|
|
| 109 |
|
|
// Adjust the day of month
|
| 110 |
|
|
initial r_day = 6'h01;
|
| 111 |
|
|
always @(posedge i_clk)
|
| 112 |
|
|
begin
|
| 113 |
|
|
if ((r_day == 0)||(r_day > 6'h31)||(r_day[3:0] > 4'h9))
|
| 114 |
|
|
r_day <= 6'h01;
|
| 115 |
|
|
else if ((i_ppd)&&(last_day_of_month))
|
| 116 |
|
|
r_day <= 6'h01;
|
| 117 |
|
|
else if ((i_ppd)&&(r_day[3:0] != 4'h9))
|
| 118 |
|
|
r_day[3:0] <= r_day[3:0] + 4'h1;
|
| 119 |
|
|
else if (i_ppd)
|
| 120 |
|
|
begin
|
| 121 |
|
|
r_day[3:0] <= 4'h0;
|
| 122 |
|
|
r_day[5:4] <= r_day[5:4] + 2'h1;
|
| 123 |
|
|
end
|
| 124 |
|
|
|
| 125 |
|
|
if ((i_wb_cyc)&&(i_wb_stb)&&(i_wb_we)&&(i_wb_data[7:0]!=8'hff))
|
| 126 |
|
|
r_day <= i_wb_data[5:0];
|
| 127 |
|
|
end
|
| 128 |
|
|
|
| 129 |
|
|
// Adjust the month of the year
|
| 130 |
|
|
initial r_mon = 5'h01;
|
| 131 |
|
|
always @(posedge i_clk)
|
| 132 |
|
|
begin
|
| 133 |
|
|
if ((r_mon == 0)||(r_mon > 5'h12)||(r_mon[3:0] > 4'h9))
|
| 134 |
|
|
r_mon <= 5'h01;
|
| 135 |
|
|
else if ((i_ppd)&&(last_day_of_year))
|
| 136 |
|
|
r_mon <= 5'h01;
|
| 137 |
|
|
else if ((i_ppd)&&(last_day_of_month)&&(r_mon[3:0] != 4'h9))
|
| 138 |
|
|
r_mon[3:0] <= r_mon[3:0] + 4'h1;
|
| 139 |
|
|
else if ((i_ppd)&&(last_day_of_month))
|
| 140 |
|
|
begin
|
| 141 |
|
|
r_mon[3:0] <= 4'h0;
|
| 142 |
|
|
r_mon[4] <= 1;
|
| 143 |
|
|
end
|
| 144 |
|
|
|
| 145 |
|
|
if ((i_wb_cyc)&&(i_wb_stb)&&(i_wb_we)&&(i_wb_data[15:8]!=8'hff))
|
| 146 |
|
|
r_mon <= i_wb_data[12:8];
|
| 147 |
|
|
end
|
| 148 |
|
|
|
| 149 |
|
|
// Adjust the year
|
| 150 |
|
|
initial r_year = 14'h2000;
|
| 151 |
|
|
always @(posedge i_clk)
|
| 152 |
|
|
begin
|
| 153 |
|
|
// Deal with any out of bounds conditions
|
| 154 |
|
|
if (r_year[3:0] > 4'h9)
|
| 155 |
|
|
r_year[3:0] <= 4'h0;
|
| 156 |
|
|
if (r_year[7:4] > 4'h9)
|
| 157 |
|
|
r_year[7:4] <= 4'h0;
|
| 158 |
|
|
if (r_year[11:8] > 4'h9)
|
| 159 |
|
|
r_year[11:8] <= 4'h0;
|
| 160 |
|
|
if ((i_ppd)&&(last_day_of_year))
|
| 161 |
|
|
begin
|
| 162 |
|
|
if (r_year[3:0] != 4'h9)
|
| 163 |
|
|
r_year[3:0] <= r_year[3:0] + 4'h1;
|
| 164 |
|
|
else begin
|
| 165 |
|
|
r_year[3:0] <= 4'h0;
|
| 166 |
|
|
if (r_year[7:4] != 4'h9)
|
| 167 |
|
|
r_year[7:4] <= r_year[7:4] + 4'h1;
|
| 168 |
|
|
else begin
|
| 169 |
|
|
r_year[7:4] <= 4'h0;
|
| 170 |
|
|
if (r_year[11:8] != 4'h9)
|
| 171 |
|
|
r_year[11:8] <= r_year[11:8]+4'h1;
|
| 172 |
|
|
else begin
|
| 173 |
|
|
r_year[11:8] <= 4'h0;
|
| 174 |
|
|
r_year[13:12] <= r_year[13:12]+2'h1;
|
| 175 |
|
|
end
|
| 176 |
|
|
end
|
| 177 |
|
|
end
|
| 178 |
|
|
end
|
| 179 |
|
|
|
| 180 |
|
|
if ((i_wb_cyc)&&(i_wb_stb)&&(i_wb_we)&&(i_wb_data[31:16]!=16'hffff))
|
| 181 |
|
|
r_year <= i_wb_data[29:16];
|
| 182 |
|
|
end
|
| 183 |
|
|
|
| 184 |
|
|
always @(posedge i_clk)
|
| 185 |
|
|
o_wb_ack <= ((i_wb_cyc)&&(i_wb_stb));
|
| 186 |
|
|
assign o_wb_stall = 1'b0;
|
| 187 |
|
|
assign o_wb_data = { 2'h0, r_year, 3'h0, r_mon, 2'h0, r_day };
|
| 188 |
|
|
endmodule
|
