Subversion Repositories RISCMCU

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----                                                                    ----

---- WISHBONE RISCMCU IP Core                                           ----

----                                                                    ----

---- This file is part of the RISCMCU project                           ----

---- http://www.opencores.org/projects/riscmcu/                         ----

----                                                                    ----

---- Description                                                        ----

---- Implementation of a RISC Microcontroller based on Atmel AVR        ----

---- AT90S1200 instruction set and features with Altera Flex10k20 FPGA. ----

----                                                                    ----

---- Author(s):                                                         ----

----    - Yap Zi He, yapzihe@hotmail.com                                ----

----                                                                    ----

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---- Copyright (C) 2001 Authors and OPENCORES.ORG                       ----

----                                                                    ----

---- This source file may be used and distributed without               ----

---- restriction provided that this copyright statement is not          ----

---- removed from the file and that any derivative work contains        ----

---- the original copyright notice and the associated disclaimer.       ----

----                                                                    ----

---- This source file is free software; you can redistribute it         ----

---- and/or modify it under the terms of the GNU Lesser General         ----

---- Public License as published by the Free Software Foundation;       ----

---- either version 2.1 of the License, or (at your option) any         ----

---- later version.                                                     ----

----                                                                    ----

---- This source 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 Lesser General Public License for more        ----

---- details.                                                           ----

----                                                                    ----

---- You should have received a copy of the GNU Lesser General          ----

---- Public License along with this source; if not, download it         ----

---- from http://www.opencores.org/lgpl.shtml                           ----

----                                                                    ----

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library ieee;

use ieee.std_logic_1164.all;

entity v_riscmcu is

        port (

                clock : in STD_LOGIC;

                reset : in STD_LOGIC;

                pinb : inout STD_LOGIC_VECTOR(7 downto 0);

                pinc : inout STD_LOGIC_VECTOR(7 downto 0);

                pind : inout STD_LOGIC_VECTOR(7 downto 0)

        );

end v_riscmcu;

architecture riscmcu of v_riscmcu is

signal ext_irq_pin, ext_timer_clk_pin : std_logic;

signal clk, clrn, div2, div4, div8, div16 : std_logic;

signal sr, reg_rd, reg_rr, c, addrbus: std_logic_vector(7 downto 0);

signal pc, offset : std_logic_vector(8 downto 0);

signal instruction, ir : std_logic_vector(15 downto 0);

signal skip, en, wr_reg : std_logic;

signal sren : std_logic_vector (6 downto 0);

signal c2a, c2b, add, subcp, logic, right, dir, pass_a : std_logic;

signal wcarry : std_logic;

signal logicsel : integer range 0 to 3;

signal rightsel : integer range 0 to 2;

signal dirsel : integer range 0 to 1;

signal addoffset, push, pull, cpse, skiptest : std_logic;

signal bclr,bset, bld, cbisbi : std_logic;

signal dest, rr, rd : integer range 0 to 15;

signal srsel : integer range 0 to 7;

signal imm_value : std_logic_vector(7 downto 0);

signal tosr : std_logic_vector (6 downto 0);

signal vec2, vec4, clr_i, set_i, clr_tov0, clr_intf, timerirq, extirq : std_logic;

signal rd_sreg,wr_sreg,rd_gimsk,wr_gimsk,rd_timsk, wr_timsk, rd_tifr,wr_tifr : std_logic;

signal rd_mcucr,wr_mcucr, rd_tccr0, wr_tccr0, rd_tcnt0,wr_tcnt0 : std_logic;

signal rd_portb,wr_portb,rd_ddrb,wr_ddrb,rd_pinb : std_logic;

signal rd_portc,wr_portc,rd_ddrc,wr_ddrc,rd_pinc : std_logic;

signal rd_portd,wr_portd,rd_ddrd,wr_ddrd,rd_pind : std_logic;

signal t_flag, c_flag : std_logic;

signal vcc, gnd : std_logic;

signal rd_ram, wr_ram, ld_mar, ld_mbr, inc_zp, dec_zp :std_logic;

signal bitsel : integer range 0 to 7;

signal set : std_logic;

signal asel : integer range 0 to 1;

signal bsel : integer range 0 to 3;

        -- Frequency Divider - Divide clock by 2(div2), 4(div4), 8(div8) and 16(div16)

        component v_freqdiv

        port (  clock : in std_logic;

                div2, div4, div8, div16 : buffer std_logic

        );

        end component;

        -- Program Counter (9 bit wide)

        component v_pc

        port (  offset : in std_logic_vector(8 downto 0);

                en, addoffset, push, pull, vec2, vec4 : in std_logic;

                clk, clrn : in std_logic;

                pc : buffer std_logic_vector(8 downto 0)

        );

        end component;

        -- Program ROM (512 words)

        component v_rom

        port (  pc : in std_logic_vector(8 downto 0);

                instruction : out std_logic_vector(15 downto 0)

        );

        end component;

        -- Instruction Register (16 bit wide)

        component v_ir

        port (  instruction : in std_logic_vector(15 downto 0);

                en, clk, clrn : in std_logic;

                ir : buffer std_logic_vector(15 downto 0);

                imm_value : out std_logic_vector(7 downto 0);

                rd, rr : out integer range 0 to 15

        );

        end component;

        -- Control Unit (with IO address decoder module inside)

        component v_controlunit

        port (  ir      : in std_logic_vector(15 downto 0);

                sr : in std_logic_vector(7 downto 0);

                clk, clrn : in std_logic;

                skip, extirq, timerirq : in std_logic;

                en : buffer std_logic;

                wr_reg : buffer std_logic;

                rd_ram, wr_ram, ld_mar, ld_mbr, inc_zp, dec_zp : out std_logic;

                sren : out std_logic_vector (6 downto 0);

                c2a,c2b : out std_logic;

                asel : out integer range 0 to 1;

                bsel : out integer range 0 to 3;

                bitsel : out integer range 0 to 7;

                set : out std_logic;

                add, subcp, logic, right, dir, pass_a : out std_logic;

                wcarry : out std_logic;

                logicsel : out integer range 0 to 3;

                rightsel : out integer range 0 to 2;

                dirsel : out integer range 0 to 1;

                addoffset : out std_logic;

                push, pull : out std_logic;

                cpse, skiptest : out std_logic;

                bclr,bset : out std_logic;

                bld : out std_logic;

                cbisbi : out std_logic;

                vec2, vec4 : buffer std_logic;

                dest : out integer range 0 to 15;

                srsel : out integer range 0 to 7;

                offset : out std_logic_vector(8 downto 0);

                clr_i, set_i, clr_intf, clr_tov0 : out std_logic;

                rd_sreg, wr_sreg : out std_logic;

                rd_gimsk, wr_gimsk, rd_timsk, wr_timsk, rd_tifr,wr_tifr : out std_logic;

                rd_mcucr,wr_mcucr, rd_tccr0, wr_tccr0, rd_tcnt0,wr_tcnt0 : out std_logic;

                rd_portb, wr_portb, rd_ddrb, wr_ddrb, rd_pinb : out std_logic;

                rd_portc, wr_portc, rd_ddrc, wr_ddrc, rd_pinc : out std_logic;

                rd_portd, wr_portd, rd_ddrd, wr_ddrd, rd_pind : out std_logic

        );

        end component;

        -- General Purpose Register (16 x 8bit)

        component v_gpr

        port (  c : in std_logic_vector(7 downto 0);

                wr_reg, inc_zp, dec_zp : in std_logic;

                rd, rr, dest : in integer range 0 to 15;

                clk, clrn : in std_logic;

                reg_rd, reg_rr, addrbus : out std_logic_vector(7 downto 0)

        );

        end component;

        -- ALU

        component v_alu

        port (  reg_rd, reg_rr, imm_value : in std_logic_vector(7 downto 0);

                c2a, c2b : in std_logic;

                asel : in integer range 0 to 1;

                bsel : in integer range 0 to 3;

                bitsel : in integer range 0 to 7;

                set : in std_logic;

                c_flag, t_flag : in std_logic;

                add, subcp, logic, right, dir, bld, cbisbi, pass_a : in std_logic;

                cpse, skiptest : in std_logic;

                wcarry : in std_logic;

                logicsel : in integer range 0 to 3;

                rightsel : in integer range 0 to 2;

                dirsel : in integer range 0 to 1;

                clk, clrn : in std_logic;

                c : buffer std_logic_vector(7 downto 0);

                tosr : buffer std_logic_vector (6 downto 0);

                skip : out std_logic

        );

        end component;

        -- Status Register (8 bit wide, flags are ITHSVNZC)

        component v_sr

        port (  clk,clrn: in std_logic;

                        sren,tosr : in std_logic_vector(6 downto 0);

                        srsel : in integer range 0 to 7;

                        clr_i,set_i,bset,bclr : in std_logic;

                        rd_sreg, wr_sreg : in std_logic;

                        c : inout std_logic_vector(7 downto 0);

                        sr : inout std_logic_vector(7 downto 0)

        );

        end component;

        -- Data RAM (128 bytes)

        component v_ram

        port (  addrbus : in std_logic_vector(7 downto 0);

                rd_ram, wr_ram, ld_mar, ld_mbr : in std_logic;

                clk, clrn : in std_logic;

                c : inout std_logic_vector(7 downto 0)

        );

        end component;

        -- Standard 8-bit I/O Port module (all ports share this same module)

        component v_port

        port (  rd_port, wr_port, rd_ddr, wr_ddr, rd_pin : in std_logic;

                clk, clrn : in std_logic;

                c : inout std_logic_vector(7 downto 0);

                pin : inout std_logic_vector(7 downto 0)

        );

        end component;

        -- 8-bit Timer with overflow interrupt request, can drive by external clock source

        component v_timer

        port (  extpin, clr_tov0 : in std_logic;

                rd_timsk, wr_timsk, rd_tifr, wr_tifr : in std_logic;

                rd_tccr0, wr_tccr0, rd_tcnt0, wr_tcnt0 : in std_logic;

                clk, clrn : in std_logic;

                c : inout std_logic_vector(7 downto 0);

                timerirq : out std_logic

        );

        end component;

        -- External Interrupt

        component v_extint

        port (  clk, clrn, extpin, clr_intf : in std_logic;

                rd_mcucr, wr_mcucr, rd_gimsk, wr_gimsk : in std_logic;

                extirq  : out std_logic;

                c : inout std_logic_vector(7 downto 0)

        );

        end component;

begin

        --U_v_freqdiv: v_freqdiv

        --      port map (clock, div2, div4, div8, div16);

        U_v_pc: v_pc

                port map (offset, en, addoffset, push, pull, vec2, vec4, clk, clrn, pc);

        U_v_rom: v_rom

                port map (pc, instruction);

        U_v_ir: v_ir

                port map (instruction, en, clk, clrn, ir, imm_value, rd, rr);

        U_v_controlunit: v_controlunit

                port map (ir, sr, clk, clrn, skip, extirq, timerirq, en, wr_reg, rd_ram, wr_ram, ld_mar, ld_mbr, inc_zp, dec_zp, sren, c2a, c2b, asel, bsel, bitsel, set, add, subcp, logic, right, dir, pass_a, wcarry, logicsel, rightsel, dirsel, addoffset, push, pull, cpse, skiptest, bclr, bset, bld, cbisbi, vec2, vec4, dest, srsel, offset, clr_i, set_i, clr_intf, clr_tov0, rd_sreg, wr_sreg, rd_gimsk, wr_gimsk, rd_timsk, wr_timsk, rd_tifr, wr_tifr, rd_mcucr, wr_mcucr, rd_tccr0, wr_tccr0, rd_tcnt0, wr_tcnt0, rd_portb, wr_portb, rd_ddrb, wr_ddrb, rd_pinb, rd_portc, wr_portc, rd_ddrc, wr_ddrc, rd_pinc, rd_portd, wr_portd, rd_ddrd, wr_ddrd, rd_pind);

        U_v_gpr: v_gpr

                port map (c, wr_reg, inc_zp, dec_zp, rd, rr, dest, clk, clrn, reg_rd, reg_rr, addrbus);

        U_v_alu: v_alu

                port map (reg_rd, reg_rr, imm_value, c2a, c2b, asel, bsel, bitsel, set, c_flag, t_flag, add, subcp, logic, right, dir, bld, cbisbi, pass_a, cpse, skiptest, wcarry, logicsel, rightsel, dirsel, clk, clrn, c, tosr, skip);

        U_v_sr: v_sr

                port map (clk, clrn, sren, tosr, srsel, clr_i, set_i, bset, bclr, rd_sreg, wr_sreg, c, sr);

        U_v_ram: v_ram

                port map (addrbus, rd_ram, wr_ram, ld_mar, ld_mbr, clk, clrn, c);

        U_v_timer: v_timer

                port map (ext_timer_clk_pin, clr_tov0, rd_timsk, wr_timsk, rd_tifr, wr_tifr, rd_tccr0, wr_tccr0, rd_tcnt0, wr_tcnt0, clk, clrn, c, timerirq);

        U_v_extint: v_extint

                port map (clk, clrn, ext_irq_pin, clr_intf, rd_mcucr, wr_mcucr, rd_gimsk, wr_gimsk, extirq, c);

        -- The same module v_port is used by 3 I/O ports, just the signals are different

        U_v_portB: v_port

                port map (rd_portb, wr_portb, rd_ddrb, wr_ddrb, rd_pinb, clk, clrn, c, pinb);

        U_v_portC: v_port

                port map (rd_portc, wr_portc, rd_ddrc, wr_ddrc, rd_pinc, clk, clrn, c, pinc);

        U_v_portD: v_port

                port map (rd_portd, wr_portd, rd_ddrd, wr_ddrd, rd_pind, clk, clrn, c, pind);

        -- Global reset, it resets ALL flip-flops and registers to the initial state (normally gnd)

        clrn <= reset;

        vcc <= '1';

        gnd <= '0';

        t_flag <= sr(6);

        c_flag <= sr(0);

        -- These are the external interrupt request pin and external timer clock source pin

        -- They share pins with the I/O ports

        -- TIPS: You can use any of the 24 I/O pins, I use pind(7) for my applications

        ext_irq_pin <= pind(2);

        ext_timer_clk_pin <= pind(4);

        -- When I use the UP1 board, the on-board 25 MHz clock is too fast and

        -- I need to divide it by 4 so that the MCU can run

        -- For waveform simulation, it does not require division (clk <= clock)

        -- TIPS: To have division, uncomment v_freqdiv module instantation on top of the page and 

        --       assign clk with div2, div4, div8 or div16

        clk <= clock;

end riscmcu;