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real 2bd06347bd
2013-11-20 17:55:16 +00:00

153 lines
4.5 KiB
VHDL

-------------------------------------------------------------------------------
-- Title : WhiteRabbit PTP Core tics
-- Project : WhiteRabbit
-------------------------------------------------------------------------------
-- File : wb_tics.vhd
-- Author : Grzegorz Daniluk
-- Company : Elproma
-- Created : 2011-04-03
-- Last update: 2011-10-04
-- Platform : FPGA-generics
-- Standard : VHDL'93
-------------------------------------------------------------------------------
-- Description:
-- WB_TICS is a simple counter with wishbone interface. Each step of a counter
-- takes 1 usec. It is used by ptp-noposix as a replace of gettimeofday()
-- function.
-------------------------------------------------------------------------------
-- Copyright (c) 2011 Grzegorz Daniluk
-------------------------------------------------------------------------------
-- Revisions :
-- Date Version Author Description
-- 2011-04-03 1.0 greg.d Created
-- 2011-10-04 1.1 twlostow added wishbone adapter
-------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library work;
use work.wishbone_pkg.all;
entity wb_watchdog is
generic (
g_interface_mode : t_wishbone_interface_mode := CLASSIC;
g_address_granularity : t_wishbone_address_granularity := WORD;
g_period : integer);
port(
rst_n_i : in std_logic;
clk_sys_i : in std_logic;
wb_adr_i : in std_logic_vector(3 downto 0);
wb_dat_i : in std_logic_vector(c_wishbone_data_width-1 downto 0);
wb_dat_o : out std_logic_vector(c_wishbone_data_width-1 downto 0);
wb_cyc_i : in std_logic;
wb_sel_i : in std_logic_vector(c_wishbone_data_width/8-1 downto 0);
wb_stb_i : in std_logic;
wb_we_i : in std_logic;
wb_ack_o : out std_logic;
wb_stall_o: out std_logic
);
end wb_tics;
architecture behaviour of wb_watchdog is
constant c_TICS_REG : std_logic_vector(1 downto 0) := "00";
signal cntr_div : unsigned(23 downto 0);
signal cntr_tics : unsigned(31 downto 0);
signal cntr_overflow : std_logic;
signal wb_in : t_wishbone_slave_in;
signal wb_out : t_wishbone_slave_out;
signal resized_addr : std_logic_vector(c_wishbone_address_width-1 downto 0);
begin
resized_addr(3 downto 0) <= wb_adr_i;
resized_addr(c_wishbone_address_width-1 downto 4) <= (others => '0');
U_Adapter : wb_slave_adapter
generic map (
g_master_use_struct => true,
g_master_mode => CLASSIC,
g_master_granularity => WORD,
g_slave_use_struct => false,
g_slave_mode => g_interface_mode,
g_slave_granularity => g_address_granularity)
port map (
clk_sys_i => clk_sys_i,
rst_n_i => rst_n_i,
master_i => wb_out,
master_o => wb_in,
sl_adr_i => resized_addr,
sl_dat_i => wb_dat_i,
sl_sel_i => wb_sel_i,
sl_cyc_i => wb_cyc_i,
sl_stb_i => wb_stb_i,
sl_we_i => wb_we_i,
sl_dat_o => wb_dat_o,
sl_ack_o => wb_ack_o,
sl_stall_o => wb_stall_o);
process(clk_sys_i)
begin
if rising_edge(clk_sys_i) then
if(rst_n_i = '0') then
cntr_div <= (others => '0');
cntr_overflow <= '0';
else
if(cntr_div = g_period-1) then
cntr_div <= (others => '0');
cntr_overflow <= '1';
else
cntr_div <= cntr_div + 1;
cntr_overflow <= '0';
end if;
end if;
end if;
end process;
--usec counter
process(clk_sys_i)
begin
if(rising_edge(clk_sys_i)) then
if(rst_n_i = '0') then
cntr_tics <= (others => '0');
elsif(cntr_overflow = '1') then
cntr_tics <= cntr_tics + 1;
end if;
end if;
end process;
--Wishbone interface
process(clk_sys_i)
begin
if rising_edge(clk_sys_i) then
if(rst_n_i = '0') then
wb_out.ack <= '0';
wb_out.dat <= (others => '0');
else
if(wb_in.stb = '1' and wb_in.cyc = '1') then
if(wb_in.we = '0') then
case wb_in.adr(1 downto 0) is
when c_TICS_REG =>
wb_out.dat <= std_logic_vector(cntr_tics);
when others =>
wb_out.dat <= (others => '0');
end case;
end if;
wb_out.ack <= '1';
else
wb_out.dat <= (others => '0');
wb_out.ack <= '0';
end if;
end if;
end if;
end process;
end behaviour;