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[/] [mips_enhanced/] [trunk/] [grlib-gpl-1.0.19-b3188/] [lib/] [gaisler/] [uart/] [apbuart.vhd] - Rev 2
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------------------------------------------------------------------------------ -- This file is a part of the GRLIB VHDL IP LIBRARY -- Copyright (C) 2003, Gaisler Research -- -- This program is free software; you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation; either version 2 of the License, 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 more details. -- -- You should have received a copy of the GNU General Public License -- along with this program; if not, write to the Free Software -- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ----------------------------------------------------------------------------- -- Entity: uart -- File: uart.vhd -- Authors: Jiri Gaisler - Gaisler Research -- Marko Isomaki - Gaisler Research -- Description: Asynchronous UART. Implements 8-bit data frame with one stop-bit. ------------------------------------------------------------------------------ library ieee; use ieee.std_logic_1164.all; --use ieee.numeric_std.all; library grlib; use grlib.amba.all; use grlib.stdlib.all; use grlib.devices.all; library gaisler; use gaisler.uart.all; --pragma translate_off use std.textio.all; --pragma translate_on entity apbuart is generic ( pindex : integer := 0; paddr : integer := 0; pmask : integer := 16#fff#; console : integer := 0; pirq : integer := 0; parity : integer := 1; flow : integer := 1; fifosize : integer range 1 to 32 := 1; abits : integer := 8); port ( rst : in std_ulogic; clk : in std_ulogic; apbi : in apb_slv_in_type; apbo : out apb_slv_out_type; uarti : in uart_in_type; uarto : out uart_out_type); end; architecture rtl of apbuart is constant REVISION : integer := 1; constant pconfig : apb_config_type := ( 0 => ahb_device_reg ( VENDOR_GAISLER, GAISLER_APBUART, 0, REVISION, pirq), 1 => apb_iobar(paddr, pmask)); type rxfsmtype is (idle, startbit, data, cparity, stopbit); type txfsmtype is (idle, data, cparity, stopbit); type fifo is array (0 to fifosize - 1) of std_logic_vector(7 downto 0); type uartregs is record rxen : std_ulogic; -- receiver enabled txen : std_ulogic; -- transmitter enabled rirqen : std_ulogic; -- receiver irq enable tirqen : std_ulogic; -- transmitter irq enable oen : std_ulogic; -- output enable parsel : std_ulogic; -- parity select paren : std_ulogic; -- parity select flow : std_ulogic; -- flow control enable loopb : std_ulogic; -- loop back mode enable debug : std_ulogic; -- debug mode enable rsempty : std_ulogic; -- receiver shift register empty (internal) tsempty : std_ulogic; -- transmitter shift register empty break : std_ulogic; -- break detected ovf : std_ulogic; -- receiver overflow parerr : std_ulogic; -- parity error frame : std_ulogic; -- framing error ctsn : std_logic_vector(1 downto 0); -- clear to send rtsn : std_ulogic; -- request to send extclken : std_ulogic; -- use external baud rate clock extclk : std_ulogic; -- rising edge detect register rhold : fifo; rshift : std_logic_vector(7 downto 0); tshift : std_logic_vector(10 downto 0); thold : fifo; irq : std_ulogic; -- tx/rx interrupt (internal) tpar : std_ulogic; -- tx data parity (internal) txstate : txfsmtype; txclk : std_logic_vector(2 downto 0); -- tx clock divider txtick : std_ulogic; -- tx clock (internal) rxstate : rxfsmtype; rxclk : std_logic_vector(2 downto 0); -- rx clock divider rxdb : std_logic_vector(1 downto 0); -- rx delay dpar : std_ulogic; -- rx data parity (internal) rxtick : std_ulogic; -- rx clock (internal) tick : std_ulogic; -- rx clock (internal) scaler : std_logic_vector(11 downto 0); brate : std_logic_vector(11 downto 0); rxf : std_logic_vector(4 downto 0); -- rx data filtering buffer txd : std_ulogic; -- transmitter data rfifoirqen : std_ulogic; -- receiver fifo interrupt enable tfifoirqen : std_ulogic; -- transmitter fifo interrupt enable --fifo counters rwaddr : std_logic_vector(log2x(fifosize) - 1 downto 0); rraddr : std_logic_vector(log2x(fifosize) - 1 downto 0); traddr : std_logic_vector(log2x(fifosize) - 1 downto 0); twaddr : std_logic_vector(log2x(fifosize) - 1 downto 0); rcnt : std_logic_vector(log2x(fifosize) downto 0); tcnt : std_logic_vector(log2x(fifosize) downto 0); end record; constant rcntzero : std_logic_vector(log2x(fifosize) downto 0) := (others => '0'); signal r, rin : uartregs; begin uartop : process(rst, r, apbi, uarti ) variable rdata : std_logic_vector(31 downto 0); variable scaler : std_logic_vector(11 downto 0); variable rxclk, txclk : std_logic_vector(2 downto 0); variable rxd, ctsn : std_ulogic; variable irq : std_logic_vector(NAHBIRQ-1 downto 0); variable paddr : std_logic_vector(7 downto 2); variable v : uartregs; variable thalffull : std_ulogic; variable rhalffull : std_ulogic; variable rfull : std_ulogic; variable tfull : std_ulogic; variable dready : std_ulogic; variable thempty : std_ulogic; --pragma translate_off variable L1 : line; variable CH : character; variable FIRST : boolean := true; variable pt : time := 0 ns; --pragma translate_on begin v := r; irq := (others => '0'); irq(pirq) := r.irq; v.irq := '0'; v.txtick := '0'; v.rxtick := '0'; v.tick := '0'; rdata := (others => '0'); v.rxdb(1) := r.rxdb(0); dready := '0'; thempty := '1'; thalffull := '1'; rhalffull := '0'; v.ctsn := r.ctsn(0) & uarti.ctsn; if fifosize = 1 then dready := r.rcnt(0); rfull := dready; tfull := r.tcnt(0); thempty := not tfull; else tfull := r.tcnt(log2x(fifosize)); rfull := r.rcnt(log2x(fifosize)); if (r.rcnt(log2x(fifosize)) or r.rcnt(log2x(fifosize) - 1)) = '1' then rhalffull := '1'; end if; if ((r.tcnt(log2x(fifosize)) or r.tcnt(log2x(fifosize) - 1))) = '1' then thalffull := '0'; end if; if r.rcnt /= rcntzero then dready := '1'; end if; if r.tcnt /= rcntzero then thempty := '0'; end if; end if; -- scaler scaler := r.scaler - 1; if (r.rxen or r.txen) = '1' then v.scaler := scaler; v.tick := scaler(11) and not r.scaler(11); if v.tick = '1' then v.scaler := r.brate; end if; end if; -- optional external uart clock v.extclk := uarti.extclk; if r.extclken = '1' then v.tick := r.extclk and not uarti.extclk; end if; -- read/write registers if (apbi.psel(pindex) and apbi.penable and (not apbi.pwrite)) = '1' then case paddr(7 downto 2) is when "000000" => rdata(7 downto 0) := r.rhold(conv_integer(r.rraddr)); if fifosize = 1 then v.rcnt(0) := '0'; else if r.rcnt /= rcntzero then v.rraddr := r.rraddr + 1; v.rcnt := r.rcnt - 1; end if; end if; when "000001" => if fifosize /= 1 then rdata (26 + log2x(fifosize) downto 26) := r.rcnt; rdata (20 + log2x(fifosize) downto 20) := r.tcnt; rdata (10 downto 7) := rfull & tfull & rhalffull & thalffull; end if; rdata(6 downto 0) := r.frame & r.parerr & r.ovf & r.break & thempty & r.tsempty & dready; --pragma translate_off if CONSOLE = 1 then rdata(2 downto 1) := "11"; end if; --pragma translate_on when "000010" => if fifosize > 1 then rdata(31) := '1'; end if; rdata(12) := r.oen; rdata(11) := r.debug; if fifosize /= 1 then rdata(10 downto 9) := r.rfifoirqen & r.tfifoirqen; end if; rdata(8 downto 0) := r.extclken & r.loopb & r.flow & r.paren & r.parsel & r.tirqen & r.rirqen & r.txen & r.rxen; when "000011" => rdata(11 downto 0) := r.brate; when "000100" => -- Read TX FIFO. if r.debug = '1' and r.tcnt /= rcntzero then rdata(7 downto 0) := r.thold(conv_integer(r.traddr)); if fifosize = 1 then v.tcnt(0) := '0'; else v.traddr := r.traddr + 1; v.tcnt := r.tcnt - 1; end if; end if; when others => null; end case; end if; paddr := "000000"; paddr(abits-1 downto 2) := apbi.paddr(abits-1 downto 2); if (apbi.psel(pindex) and apbi.penable and apbi.pwrite) = '1' then case paddr(7 downto 2) is when "000000" => when "000001" => v.frame := apbi.pwdata(6); v.parerr := apbi.pwdata(5); v.ovf := apbi.pwdata(4); v.break := apbi.pwdata(3); when "000010" => v.oen := apbi.pwdata(12); v.debug := apbi.pwdata(11); if fifosize /= 1 then v.rfifoirqen := apbi.pwdata(10); v.tfifoirqen := apbi.pwdata(9); end if; v.extclken := apbi.pwdata(8); v.loopb := apbi.pwdata(7); v.flow := apbi.pwdata(6); v.paren := apbi.pwdata(5); v.parsel := apbi.pwdata(4); v.tirqen := apbi.pwdata(3); v.rirqen := apbi.pwdata(2); v.txen := apbi.pwdata(1); v.rxen := apbi.pwdata(0); when "000011" => v.brate := apbi.pwdata(11 downto 0); v.scaler := apbi.pwdata(11 downto 0); when "000100" => -- Write RX fifo and generate irq if flow /= 0 then v.rhold(conv_integer(r.rwaddr)) := apbi.pwdata(7 downto 0); if fifosize = 1 then v.rcnt(0) := '1'; else v.rwaddr := r.rwaddr + 1; v.rcnt := v.rcnt + 1; end if; if r.debug = '1' then v.irq := v.irq or r.rirqen; end if; end if; when others => null; end case; end if; -- tx clock txclk := r.txclk + 1; if r.tick = '1' then v.txclk := txclk; v.txtick := r.txclk(2) and not txclk(2); end if; -- rx clock rxclk := r.rxclk + 1; if r.tick = '1' then v.rxclk := rxclk; v.rxtick := r.rxclk(2) and not rxclk(2); end if; -- filter rx data -- v.rxf := r.rxf(6 downto 0) & uarti.rxd; -- if ((r.rxf(7) & r.rxf(7) & r.rxf(7) & r.rxf(7) & r.rxf(7) & r.rxf(7) & -- r.rxf(7)) = r.rxf(6 downto 0)) -- then v.rxdb(0) := r.rxf(7); end if; v.rxf(1 downto 0) := r.rxf(0) & uarti.rxd; -- meta-stability filter if r.tick = '1' then v.rxf(4 downto 2) := r.rxf(3 downto 1); end if; v.rxdb(0) := (r.rxf(4) and r.rxf(3)) or (r.rxf(4) and r.rxf(2)) or (r.rxf(3) and r.rxf(2)); -- loop-back mode if r.loopb = '1' then v.rxdb(0) := r.tshift(0); ctsn := dready and not r.rsempty; elsif (flow = 1) then ctsn := r.ctsn(1); else ctsn := '0'; end if; rxd := r.rxdb(0); -- transmitter operation case r.txstate is when idle => -- idle state if (r.txtick = '1') then v.tsempty := '1'; end if; if ((not r.debug and r.txen and (not thempty) and r.txtick) and ((not ctsn) or not r.flow)) = '1' then v.txstate := data; v.tpar := r.parsel; v.tsempty := '0'; v.txclk := "00" & r.tick; v.txtick := '0'; v.tshift := "10" & r.thold(conv_integer(r.traddr)) & '0'; if fifosize = 1 then v.irq := r.irq or r.tirqen; v.tcnt(0) := '0'; else v.traddr := r.traddr + 1; v.tcnt := r.tcnt - 1; end if; end if; when data => -- transmit data frame if r.txtick = '1' then v.tpar := r.tpar xor r.tshift(1); v.tshift := '1' & r.tshift(10 downto 1); if r.tshift(10 downto 1) = "1111111110" then if r.paren = '1' then v.tshift(0) := r.tpar; v.txstate := cparity; else v.tshift(0) := '1'; v.txstate := stopbit; end if; end if; end if; when cparity => -- transmit parity bit if r.txtick = '1' then v.tshift := '1' & r.tshift(10 downto 1); v.txstate := stopbit; end if; when stopbit => -- transmit stop bit if r.txtick = '1' then v.tshift := '1' & r.tshift(10 downto 1); v.txstate := idle; end if; end case; -- writing of tx data register must be done after tx fsm to get correct -- operation of thempty flag if (apbi.psel(pindex) and apbi.penable and apbi.pwrite) = '1' then case paddr(4 downto 2) is when "000" => if fifosize = 1 then v.thold(0) := apbi.pwdata(7 downto 0); v.tcnt(0) := '1'; else v.thold(conv_integer(r.twaddr)) := apbi.pwdata(7 downto 0); if not (tfull = '1') then v.twaddr := r.twaddr + 1; v.tcnt := v.tcnt + 1; end if; end if; --pragma translate_off if CONSOLE = 1 then if first then L1:= new string'(""); first := false; end if; --' if apbi.penable'event then --' CH := character'val(conv_integer(apbi.pwdata(7 downto 0))); --' if CH = CR then std.textio.writeline(OUTPUT, L1); elsif CH /= LF then std.textio.write(L1,CH); end if; pt := now; end if; end if; --pragma translate_on when others => null; end case; end if; -- receiver operation case r.rxstate is when idle => -- wait for start bit if ((r.rsempty = '0') and not (rfull = '1')) then v.rsempty := '1'; v.rhold(conv_integer(r.rwaddr)) := r.rshift; if fifosize = 1 then v.rcnt(0) := '1'; else v.rwaddr := r.rwaddr + 1; v.rcnt := v.rcnt + 1; end if; end if; if (r.rxen and r.rxdb(1) and (not rxd)) = '1' then v.rxstate := startbit; v.rshift := (others => '1'); v.rxclk := "100"; if v.rsempty = '0' then v.ovf := '1'; end if; v.rsempty := '0'; v.rxtick := '0'; end if; when startbit => -- check validity of start bit if r.rxtick = '1' then if rxd = '0' then v.rshift := rxd & r.rshift(7 downto 1); v.rxstate := data; v.dpar := r.parsel; else v.rxstate := idle; end if; end if; when data => -- receive data frame if r.rxtick = '1' then v.dpar := r.dpar xor rxd; v.rshift := rxd & r.rshift(7 downto 1); if r.rshift(0) = '0' then if r.paren = '1' then v.rxstate := cparity; else v.rxstate := stopbit; v.dpar := '0'; end if; end if; end if; when cparity => -- receive parity bit if r.rxtick = '1' then v.dpar := r.dpar xor rxd; v.rxstate := stopbit; end if; when stopbit => -- receive stop bit if r.rxtick = '1' then v.irq := v.irq or r.rirqen; -- make sure no tx irqs are lost ! if rxd = '1' then v.parerr := r.parerr or r.dpar; v.rsempty := r.dpar; if not (rfull = '1') and (r.dpar = '0') then v.rsempty := '1'; v.rhold(conv_integer(r.rwaddr)) := r.rshift; if fifosize = 1 then v.rcnt(0) := '1'; else v.rwaddr := r.rwaddr + 1; v.rcnt := v.rcnt + 1; end if; end if; else if r.rshift = "00000000" then v.break := '1'; else v.frame := '1'; end if; v.rsempty := '1'; end if; v.rxstate := idle; end if; end case; if r.rxtick = '1' then v.rtsn := (rfull and not r.rsempty) or r.loopb; end if; v.txd := r.tshift(0) or r.loopb or r.debug; if fifosize /= 1 then if thempty = '0' and v.tcnt = rcntzero then v.irq := v.irq or r.tirqen; end if; v.irq := v.irq or (r.tfifoirqen and r.txen and thalffull); v.irq := v.irq or (r.rfifoirqen and r.rxen and rhalffull); end if; -- reset operation if rst = '0' then v.frame := '0'; v.rsempty := '1'; v.parerr := '0'; v.ovf := '0'; v.break := '0'; v.tsempty := '1'; v.txen := '0'; v.rxen := '0'; v.txstate := idle; v.rxstate := idle; v.tshift(0) := '1'; v.extclken := '0'; v.rtsn := '1'; v.flow := '0'; v.txclk := (others => '0'); v.rxclk := (others => '0'); v.rcnt := (others => '0'); v.tcnt := (others => '0'); v.rwaddr := (others => '0'); v.twaddr := (others => '0'); v.rraddr := (others => '0'); v.traddr := (others => '0'); end if; -- update registers rin <= v; -- drive outputs uarto.txd <= r.txd; uarto.rtsn <= r.rtsn; uarto.scaler <= "000000" & r.scaler; uarto.txen <= r.oen; uarto.rxen <= r.rxen; apbo.prdata <= rdata; apbo.pirq <= irq; apbo.pindex <= pindex; uarto.txen <= r.txen; uarto.rxen <= r.rxen; end process; apbo.pconfig <= pconfig; regs : process(clk) begin if rising_edge(clk) then r <= rin; end if; end process; -- pragma translate_off bootmsg : report_version generic map ("apbuart" & tost(pindex) & ": Generic UART rev " & tost(REVISION) & ", fifo " & tost(fifosize) & ", irq " & tost(pirq)); -- pragma translate_on end;