library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; -- -- Copyright (C) 2007, Peter C. Wallace, Mesa Electronics -- http://www.mesanet.com -- -- This program is is licensed under a disjunctive dual license giving you -- the choice of one of the two following sets of free software/open source -- licensing terms: -- -- * GNU General Public License (GPL), version 2.0 or later -- * 3-clause BSD License -- -- -- The GNU GPL License: -- -- 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA -- -- -- The 3-clause BSD License: -- -- Redistribution and use in source and binary forms, with or without -- modification, are permitted provided that the following conditions -- are met: -- -- * Redistributions of source code must retain the above copyright -- notice, this list of conditions and the following disclaimer. -- -- * Redistributions in binary form must reproduce the above -- copyright notice, this list of conditions and the following -- disclaimer in the documentation and/or other materials -- provided with the distribution. -- -- * Neither the name of Mesa Electronics nor the names of its -- contributors may be used to endorse or promote products -- derived from this software without specific prior written -- permission. -- -- -- Disclaimer: -- -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS -- FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -- COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -- BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -- ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- use work.log2.all; use work.parity.all; entity pktuartx is generic (MaxFrameSize: integer ); -- in bytes (-1) maximum is 2K bytes Port (clk : in std_logic; ibus : in std_logic_vector(31 downto 0); obus : out std_logic_vector(31 downto 0); pushdata : in std_logic; pushsc: in std_logic; readsc: in std_logic; loadbitrate : in std_logic; readbitrate : in std_logic; loadmode : in std_logic; readmode : in std_logic; drven : out std_logic; txdata : out std_logic ); end pktuartx; architecture Behavioral of pktuartx is -- buffer related signals signal InAdd: std_logic_vector(log2(MaxFrameSize) -3 downto 0); signal OutAdd: std_logic_vector(log2(MaxFrameSize) -3 downto 0); signal OutData: std_logic_vector(31 downto 0); signal ReadData: std_logic; signal FrameBufferEmpty: std_logic; -- frame FIFO related signals signal PopSC: std_logic; signal SFrameCount: std_logic_vector(4 downto 0); signal SCPopAdd: std_logic_vector(3 downto 0); signal SCFIFOError: std_logic; signal SCFIFOEmpty : std_logic; signal SCPopData: std_logic_vector(log2(maxFrameSize)-1 downto 0); -- uart interface related signals constant DDSWidth : integer := 24; signal BitrateDDSReg : std_logic_vector(DDSWidth-1 downto 0); signal BitrateDDSAccum : std_logic_vector(DDSWidth-1 downto 0); alias DDSMSB : std_logic is BitrateDDSAccum(DDSWidth-1); signal OldDDSMSB: std_logic; signal SampleTime: std_logic; signal DelayTime: std_logic; signal BitCount : std_logic_vector(3 downto 0); signal BytePointer : std_logic_vector(1 downto 0) := "00"; signal SReg: std_logic_vector(11 downto 0) := x"FFF"; signal SendData: std_logic_vector(7 downto 0); signal SendCount: std_logic_vector(log2(MaxFrameSize)-1 downto 0); signal Clear: std_logic; alias SregData: std_logic_vector(7 downto 0)is SReg(9 downto 2); alias StartBit: std_logic is Sreg(1); alias Parity_or_StopBit: std_logic is Sreg(10); --parity if enabled, stop bit if no parity alias PStopBit: std_logic is Sreg(11); --stop bit if parity enabled alias IdleBit: std_logic is Sreg(0); signal Go: std_logic := '0'; signal FDGo: std_logic := '0'; signal SCNZ: std_logic := '0'; signal ModeReg: std_logic_vector(18 downto 0); alias FrameDelay: std_logic_vector(7 downto 0) is ModeReg(15 downto 8); signal FrameDelayCount: std_logic_vector(7 downto 0); alias DriveEnDelay: std_logic_vector(3 downto 0) is ModeReg (3 downto 0); signal DriveDelayCount: std_logic_vector(3 downto 0); alias DriveEnAuto: std_logic is ModeReg(5); alias DriveEnBit: std_logic is ModeReg(6); alias UseParity: std_logic is ModeReg(17); alias OddParity: std_logic is ModeReg(18); signal DriveEnable: std_logic; signal DriveEnHold: std_logic; signal WaitingForDrive: std_logic; component SRL16E -- generic (INIT : bit_vector); -- port (D : in std_logic; CE : in std_logic; CLK : in std_logic; A0 : in std_logic; A1 : in std_logic; A2 : in std_logic; A3 : in std_logic; Q : out std_logic); end component; begin buffram : entity work.dpram generic map ( width => 32, depth => MaxFrameSize/4 ) port map( addra => InAdd, addrb => OutAdd, clk => clk, dina => ibus, -- douta => doutb => OutData, wea => pushdata ); abuf: process (clk) begin if rising_edge(clk) then if pushdata = '1' then InAdd <= InAdd+1; end if; if ReadData = '1' then OutAdd <= OutAdd +1; end if; if Clear = '1' then InAdd <= (others => '0'); OutAdd <= (others => '0'); end if; end if; -- clk if InAdd = OutAdd then FrameBufferEmpty <= '1'; else FrameBufferEmpty <= '0'; end if; end process abuf; fifosrl: for i in 0 to log2(MaxFrameSize)-1 generate asr16e: SRL16E generic map (x"0000") port map( D => ibus(i), CE => pushsc, CLK => clk, A0 => SCPopAdd(0), A1 => SCPopAdd(1), A2 => SCPopAdd(2), A3 => SCPopAdd(3), Q => SCPopData(i) ); end generate; ascfifo: process (clk,SCPopData,SFrameCount) -- send counterrp32 6300 fifo begin if rising_edge(clk) then if pushsc = '1' and PopSC = '0' then if SFrameCount /= 16 then -- a push -- always increment the data counter if not full SFrameCount <= SFrameCount +1; SCPopAdd <= SCPopAdd +1; -- popadd must follow data down shiftreg else SCFIFOError <= '1'; end if; end if; if (PopSC = '1') and (pushsc = '0') and (SCFIFOEmpty = '0') then -- a pop -- always decrement the data counter if not empty SFrameCount <= SFrameCount -1; SCPopAdd <= SCPopAdd -1; end if; -- if both push and pop are asserted we dont change either counter if Clear = '1' then -- a Clear fifo SCPopadd <= (others => '1'); SFrameCount <= (others => '0'); SCFIFOError <= '0'; end if; end if; -- clk rise if SFrameCount = 0 then SCFIFOEmpty <= '1'; else SCFIFOEmpty <= '0'; end if; end process ascfifo; asimplepktuarttx: process (clk,loadmode,OldDDSMSB,BitRateDDSAccum,DriveDelayCount, DriveEnable,ModeReg,Go,BytePointer,OutData,readbitrate, readmode,ibus,BitRateDDSReg,FDGo,WaitingForDrive,SReg, SCNZ,SFrameCount,SendCount,SCFIFOError,SCFIFOEmpty) begin if rising_edge(clk) then if Go = '1' or FDGo = '1' then BitRateDDSAccum <= BitRateDDSAccum - BitRateDDSReg; if FDGo = '0' then if SampleTime = '1' then SReg <= '1' & SReg(11 downto 1); -- right shift = LSb first BitCount <= BitCount -1; if BitCount = 0 then Go <= '0'; end if; end if; end if; if FDGO = '1' then -- frame delay if DelayTime = '1' then FrameDelayCount <= FrameDelayCount -1; if FrameDelayCount = x"01" then FDGo <= '0'; end if; end if; end if; else BitRateDDSAccum <= (others => '0'); end if; if Go = '0' and FDGo = '0' and DriveEnHold = '0' then -- prepare to send StartBit <= '0'; IdleBit <= '1'; PStopBit <= '1'; if UseParity = '0' then BitCount <= "1010"; -- 10 bits for 1 start 8 data 1 stop else BitCount <= "1011"; -- 11 bits for 1 start 8 data 1 parity 1 stop end if; if SendCount /= 0 then -- start byte send -- UART SReg not busy and we have data SRegData <= SendData; if UseParity = '0' then Parity_or_StopBit <= '1'; else Parity_or_StopBit <= (parity(SendData) xor OddParity); end if; Go <= '1'; BytePointer <= BytePointer +1; SendCount <= SendCount -1; if BytePointer = "11" then ReadData <= '1'; -- advance read data pointer end if; SCNZ <= '1'; else -- SendCount = 0 if SCFIFOEmpty = '0' then -- more frames to send SendCount <= SCPopData; PopSC <= '1'; end if; if SCNZ = '1' then -- just at end of frame if BytePointer /= "00" then -- discard partial data BytePointer <= "00"; ReadData <= '1'; end if; FDGo <= '1'; FrameDelayCount <= FrameDelay; SCNZ <= '0'; end if; end if; end if; if Clear = '1' then SendCount <= (others => '0'); BytePointer <= "00"; Go <= '0'; FDGo <='0'; SCNZ <='0'; end if; if ReadData = '1' then ReadData <= '0'; end if; if PopSC = '1' then PopSC <= '0'; end if; if DriveEnable = '0' then DriveDelayCount <= DriveEnDelay; else if WaitingForDrive = '1' then DriveDelayCount <= DriveDelayCount -1; end if; end if; OldDDSMSB <= DDSMSB; if loadbitrate = '1' then BitRateDDSReg <= ibus(DDSWidth-1 downto 0); end if; if loadmode = '1' and ibus(31) = '0' then ModeReg <= ibus(18 downto 0); end if; end if; -- clk if loadmode = '1' and ibus(16) = '1' then Clear <= '1'; else Clear <= '0'; end if; SampleTime <= (not OldDDSMSB) and DDSMSB; DelayTime <= OldDDSMSB and (not DDSMSB); if DriveDelayCount /= 0 then WaitingForDrive <= '1'; else WaitingForDrive <= '0'; end if; DriveEnHold <= (not DriveEnable) or WaitingForDrive; if DriveEnAuto = '1' then DriveEnable <= (Go or SCNZ or (not SCFIFOEmpty)); -- 09/08/23 Drive enable should -- when there is data to xmit -- DriveEnable <= (Go or FDGo or SCNZ or (not SCFIFOEmpty));-- not be extended by interframe delay -- when there is data to xmit else DriveEnable <= DriveEnBit; end if; case BytePointer is when "00" => SendData <= OutData(7 downto 0); when "01" => SendData <= OutData(15 downto 8); when "10" => SendData <= OutData(23 downto 16); when "11" => SendData <= OutData(31 downto 24); when others => null; end case; obus <= (others => 'Z'); if readsc = '1' then obus(log2(MaxFrameSize)-1 downto 0) <= SendCount; obus(31 downto log2(MaxFrameSize)) <= (others => '0'); end if; if readbitrate = '1' then obus(DDSWidth-1 downto 0) <= BitRateDDSReg; end if; if readmode = '1' then obus(3 downto 0) <= ModeReg(3 downto 0); obus(4) <= SCFIFOError; obus(6 downto 5) <= ModeReg(6 downto 5); obus(7) <= Go or FDGo or (not SCFIFOEmpty) or SCNZ; obus(15 downto 8) <= ModeReg(15 downto 8); obus(20 downto 16) <= SFrameCount; obus(21) <= not FrameBufferEmpty; obus(31 downto 22) <= (others => '0'); end if; txdata<= SReg(0); drven <= DriveEnable; end process asimplepktuarttx; end Behavioral;