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wfjm.w11/rtl/bplib/bpgen/rgbdrv_master.vhd

104 lines
2.8 KiB
VHDL

-- $Id: rgbdrv_master.vhd 984 2018-01-02 20:56:27Z mueller $
--
-- Copyright 2016- by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>
--
-- This program is free software; you may redistribute and/or modify it under
-- the terms of the GNU General Public License as published by the Free
-- Software Foundation, either version 3, 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 complete details.
--
------------------------------------------------------------------------------
-- Module Name: rgbdrv_master - syn
-- Description: rgbled driver: master
--
-- Dependencies: -
-- Test bench: -
-- Target Devices: generic
-- Tool versions: viv 2015.4; ghdl 0.31
--
-- Revision History:
-- Date Rev Version Comment
-- 2016-02-20 734 1.0 Initial version
------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.slvtypes.all;
entity rgbdrv_master is -- rgbled driver: master
generic (
DWIDTH : positive := 8); -- dimmer width (must be >= 1)
port (
CLK : in slbit; -- clock
RESET : in slbit := '0'; -- reset
CE_USEC : in slbit; -- 1 us clock enable
RGBCNTL : out slv3; -- rgb control
DIMCNTL : out slv(DWIDTH-1 downto 0) -- dim control
);
end rgbdrv_master;
architecture syn of rgbdrv_master is
type regs_type is record
rgbena : slv3; -- rgb enables
dimcnt : slv(DWIDTH-1 downto 0); -- dim counter
end record regs_type;
constant dimones : slv(DWIDTH-1 downto 0) := (others=>'1');
constant regs_init : regs_type := (
"001", -- rgbena
dimones -- dimcnt
);
signal R_REGS : regs_type := regs_init; -- state registers
signal N_REGS : regs_type := regs_init; -- next value state regs
begin
proc_regs: process (CLK)
begin
if rising_edge(CLK) then
if RESET = '1' then
R_REGS <= regs_init;
else
R_REGS <= N_REGS;
end if;
end if;
end process proc_regs;
proc_next: process (R_REGS, CE_USEC)
variable r : regs_type := regs_init;
variable n : regs_type := regs_init;
begin
r := R_REGS;
n := R_REGS;
if CE_USEC = '1' then
n.dimcnt := slv(unsigned(r.dimcnt) + 1);
if r.dimcnt = dimones then
n.rgbena(2) := r.rgbena(1);
n.rgbena(1) := r.rgbena(0);
n.rgbena(0) := r.rgbena(2);
end if;
end if;
N_REGS <= n;
end process proc_next;
RGBCNTL <= R_REGS.rgbena;
DIMCNTL <= R_REGS.dimcnt;
end syn;