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URL https://opencores.org/ocsvn/t65/t65/trunk

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  • This comparison shows the changes necessary to convert path 
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    from Rev 8 to Rev 9
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Rev 8 → Rev 9

/trunk/rtl/vhdl/T16450.vhd
1,10 → 1,8
--
-- 16450 compatible UART with synchronous bus interface
-- RClk/BaudOut is XIn enable instead of actual clock
-- No break detection, no modem status change detection
-- Only one stop bit supported
--
-- Version : 0208
-- Version : 0249
--
-- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org)
--
47,6 → 45,11
--
-- File history :
--
-- 0208 : First release
--
-- 0249 : Fixed interrupt and baud rate bugs found by Andy Dyer
-- Added modem status and break detection
-- Added support for 1.5 and 2 stop bits
 
library IEEE;
use IEEE.std_logic_1164.all;
95,7 → 98,10
signal DM0 : std_logic_vector(7 downto 0);
signal DM1 : std_logic_vector(7 downto 0);
 
signal MSR_In : std_logic_vector(3 downto 0);
 
signal Bit_Phase : unsigned(3 downto 0);
signal Brk_Cnt : unsigned(3 downto 0);
signal RX_Filtered : std_logic;
signal RX_ShiftReg : std_logic_vector(7 downto 0);
signal RX_Bit_Cnt : integer range 0 to 11;
106,6 → 112,8
signal TX_ShiftReg : std_logic_vector(7 downto 0);
signal TX_Bit_Cnt : integer range 0 to 11;
signal TX_Parity : std_logic;
signal TX_Next_Is_Stop : std_logic;
signal TX_Stop_Bit : std_logic;
signal TXD : std_logic;
 
begin
139,7 → 147,7
IER <= "00000000";
LCR <= "00000000";
MCR <= "00000000";
MSR <= "00000000";
MSR(3 downto 0) <= "0000";
SCR <= "00000000"; -- ??
DLL <= "00000000"; -- ??
DLM <= "00000000"; -- ??
167,11 → 175,31
when others =>
end case;
end if;
if Rd_n = '0' and CS_n = '0' and A = "110" then
MSR(3 downto 0) <= "0000";
end if;
if MSR(4) /= MSR_In(0) then
MSR(0) <= '1';
end if;
if MSR(5) /= MSR_In(1) then
MSR(1) <= '1';
end if;
if MSR(6) = '0' and MSR_In(2) = '1' then
MSR(2) <= '1';
end if;
if MSR(7) /= MSR_In(3) then
MSR(3) <= '1';
end if;
end if;
end process;
process (XIn)
begin
if XIn'event and XIn = '1' then
if MCR(4) = '0' then
MSR(4) <= CTS_n;
MSR(5) <= DSR_n;
MSR(6) <= RI_n;
MSR(7) <= DCD_n;
MSR(4) <= MSR_In(0);
MSR(5) <= MSR_In(1);
MSR(6) <= MSR_In(2);
MSR(7) <= MSR_In(3);
else
MSR(4) <= MCR(1);
MSR(5) <= MCR(0);
178,6 → 206,10
MSR(6) <= MCR(2);
MSR(7) <= MCR(3);
end if;
MSR_In(0) <= CTS_n;
MSR_In(1) <= DSR_n;
MSR_In(2) <= RI_n;
MSR_In(3) <= DCD_n;
end if;
end process;
 
184,9 → 216,9
IIR(7 downto 3) <= "00000";
IIR(2 downto 0) <=
"110" when IER(2) = '1' and LSR(4 downto 1) /= "0000" else
"110" when (IER(0) and LSR(0)) = '1' else
"100" when (IER(0) and LSR(0)) = '1' else
"010" when (IER(1) and LSR(5)) = '1' else
"001" when IER(3) = '1' and ((MCR(4) = '0' and MSR(3 downto 0) /= "0000") or
"000" when IER(3) = '1' and ((MCR(4) = '0' and MSR(3 downto 0) /= "0000") or
(MCR(4) = '1' and MCR(3 downto 0) /= "0000")) else
"001";
 
195,10 → 227,10
variable Baud_Cnt : unsigned(15 downto 0);
begin
if MR_n = '0' then
Baud_Cnt := "0000000000000001";
Baud_Cnt := "0000000000000000";
BaudOut <= '0';
elsif XIn'event and XIn = '1' then
if Baud_Cnt = "0000000000000001" or (Wr_n = '0' and CS_n = '0' and A(2 downto 1) = "00" and LCR(7) = '1') then
if Baud_Cnt(15 downto 1) = "000000000000000" or (Wr_n = '0' and CS_n = '0' and A(2 downto 1) = "00" and LCR(7) = '1') then
Baud_Cnt(15 downto 8) := unsigned(DLM);
Baud_Cnt(7 downto 0) := unsigned(DLL);
BaudOut <= '1';
237,6 → 269,7
RBR <= "00000000";
LSR(4 downto 0) <= "00000";
Bit_Phase <= "0000";
Brk_Cnt <= "0000";
RX_ShiftReg(7 downto 0) <= "00000000";
RX_Bit_Cnt <= 0;
RX_Parity <= '0';
245,6 → 278,7
LSR(0) <= '0'; -- DR
end if;
if A = "101" and Rd_n = '0' and CS_n = '0' then
LSR(4) <= '0'; -- BI
LSR(3) <= '0'; -- FE
LSR(2) <= '0'; -- PE
LSR(1) <= '0'; -- OE
255,6 → 289,16
else
Bit_Phase <= Bit_Phase + 1;
end if;
if Bit_Phase = "1111" then
if RX_Filtered = '1' then
Brk_Cnt <= "0000";
else
Brk_Cnt <= Brk_Cnt + 1;
end if;
if Brk_Cnt = "1100" then
LSR(4) <= '1'; -- BI
end if;
end if;
if RX_Bit_Cnt = 0 then
if Bit_Phase = "0111" then
RX_Bit_Cnt <= RX_Bit_Cnt + 1;
318,18 → 362,33
 
-- Transmit bit tick
process (MR_n, XIn)
variable TX_Cnt : unsigned(3 downto 0);
variable TX_Cnt : unsigned(4 downto 0);
begin
if MR_n = '0' then
TX_Cnt := "0000";
TX_Cnt := "00000";
TX_Tick <= '0';
elsif XIn'event and XIn = '1' then
TX_Tick <= '0';
if RClk = '1' then
if TX_Cnt = "1111" then
TX_Tick <= '1';
TX_Cnt := TX_Cnt + 1;
if LCR(2) = '1' and TX_Stop_Bit = '1' then
if LCR(1 downto 0) = "00" then
if TX_Cnt = "10111" then
TX_Tick <= '1';
TX_Cnt(3 downto 0) := "0000";
end if;
else
if TX_Cnt = "11111" then
TX_Tick <= '1';
TX_Cnt(3 downto 0) := "0000";
end if;
end if;
else
TX_Cnt(4) := '1';
if TX_Cnt(3 downto 0) = "1111" then
TX_Tick <= '1';
end if;
end if;
TX_Cnt := TX_Cnt + 1;
end if;
end if;
end process;
343,8 → 402,12
TX_ShiftReg <= (others => '0');
TXD <= '1';
TX_Parity <= '0';
TX_Next_Is_Stop <= '0';
TX_Stop_Bit <= '0';
elsif XIn'event and XIn = '1' then
if TX_Tick = '1' then
TX_Next_Is_Stop <= '0';
TX_Stop_Bit <= TX_Next_Is_Stop;
case TX_Bit_Cnt is
when 0 =>
if LSR(5) <= '0' then -- THRE
363,6 → 426,7
TXD <= not LCR(4);
end if;
TX_Bit_Cnt <= 0;
TX_Next_Is_Stop <= '1';
when others =>
TX_Bit_Cnt <= TX_Bit_Cnt + 1;
if (TX_Bit_Cnt = 9 and LCR(1 downto 0) = "11") or
372,6 → 436,8
TX_Bit_Cnt <= 0;
if LCR(3) = '1' then -- PEN
TX_Bit_Cnt <= 10;
else
TX_Next_Is_Stop <= '1';
end if;
LSR(6) <= '1'; -- TEMT
end if;

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