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[/] [z80soc/] [tags/] [z80soc05/] [S3E/] [clk_div.vhd] - Rev 40
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library IEEE; use IEEE.STD_LOGIC_1164.all; use IEEE.STD_LOGIC_ARITH.all; use IEEE.STD_LOGIC_UNSIGNED.all; ENTITY clk_div IS PORT ( clock_25Mhz : IN STD_LOGIC; clock_1MHz : OUT STD_LOGIC; clock_100KHz : OUT STD_LOGIC; clock_10KHz : OUT STD_LOGIC; clock_1KHz : OUT STD_LOGIC; clock_100Hz : OUT STD_LOGIC; clock_10Hz : OUT STD_LOGIC; clock_1Hz : OUT STD_LOGIC); END clk_div; ARCHITECTURE a OF clk_div IS SIGNAL count_1Mhz: STD_LOGIC_VECTOR(4 DOWNTO 0); SIGNAL count_100Khz, count_10Khz, count_1Khz : STD_LOGIC_VECTOR(2 DOWNTO 0); SIGNAL count_100hz, count_10hz, count_1hz : STD_LOGIC_VECTOR(2 DOWNTO 0); SIGNAL clock_1Mhz_int, clock_100Khz_int, clock_10Khz_int, clock_1Khz_int: STD_LOGIC; SIGNAL clock_100hz_int, clock_10Hz_int, clock_1Hz_int : STD_LOGIC; BEGIN PROCESS BEGIN -- Divide by 25 WAIT UNTIL clock_25Mhz'EVENT and clock_25Mhz = '1'; IF count_1Mhz < 24 THEN count_1Mhz <= count_1Mhz + 1; ELSE count_1Mhz <= "00000"; END IF; IF count_1Mhz < 12 THEN clock_1Mhz_int <= '0'; ELSE clock_1Mhz_int <= '1'; END IF; -- Ripple clocks are used in this code to save prescalar hardware -- Sync all clock prescalar outputs back to master clock signal clock_1Mhz <= clock_1Mhz_int; clock_100Khz <= clock_100Khz_int; clock_10Khz <= clock_10Khz_int; clock_1Khz <= clock_1Khz_int; clock_100hz <= clock_100hz_int; clock_10hz <= clock_10hz_int; clock_1hz <= clock_1hz_int; END PROCESS; -- Divide by 10 PROCESS BEGIN WAIT UNTIL clock_1Mhz_int'EVENT and clock_1Mhz_int = '1'; IF count_100Khz /= 4 THEN count_100Khz <= count_100Khz + 1; ELSE count_100khz <= "000"; clock_100Khz_int <= NOT clock_100Khz_int; END IF; END PROCESS; -- Divide by 10 PROCESS BEGIN WAIT UNTIL clock_100Khz_int'EVENT and clock_100Khz_int = '1'; IF count_10Khz /= 4 THEN count_10Khz <= count_10Khz + 1; ELSE count_10khz <= "000"; clock_10Khz_int <= NOT clock_10Khz_int; END IF; END PROCESS; -- Divide by 10 PROCESS BEGIN WAIT UNTIL clock_10Khz_int'EVENT and clock_10Khz_int = '1'; IF count_1Khz /= 4 THEN count_1Khz <= count_1Khz + 1; ELSE count_1khz <= "000"; clock_1Khz_int <= NOT clock_1Khz_int; END IF; END PROCESS; -- Divide by 10 PROCESS BEGIN WAIT UNTIL clock_1Khz_int'EVENT and clock_1Khz_int = '1'; IF count_100hz /= 4 THEN count_100hz <= count_100hz + 1; ELSE count_100hz <= "000"; clock_100hz_int <= NOT clock_100hz_int; END IF; END PROCESS; -- Divide by 10 PROCESS BEGIN WAIT UNTIL clock_100hz_int'EVENT and clock_100hz_int = '1'; IF count_10hz /= 4 THEN count_10hz <= count_10hz + 1; ELSE count_10hz <= "000"; clock_10hz_int <= NOT clock_10hz_int; END IF; END PROCESS; -- Divide by 10 PROCESS BEGIN WAIT UNTIL clock_10hz_int'EVENT and clock_10hz_int = '1'; IF count_1hz /= 4 THEN count_1hz <= count_1hz + 1; ELSE count_1hz <= "000"; clock_1hz_int <= NOT clock_1hz_int; END IF; END PROCESS; END a;
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