---------------------------------------------------------------------
|
---------------------------------------------------------------------
|
---- ----
|
---- ----
|
---- WISHBONE revB2 compl. I2C Master Core; top level ----
|
---- WISHBONE revB2 compl. I2C Master Core; top level ----
|
---- ----
|
---- ----
|
---- ----
|
---- ----
|
---- Author: Richard Herveille ----
|
---- Author: Richard Herveille ----
|
---- richard@asics.ws ----
|
---- richard@asics.ws ----
|
---- www.asics.ws ----
|
---- www.asics.ws ----
|
---- ----
|
---- ----
|
---- Downloaded from: http://www.opencores.org/projects/i2c/ ----
|
---- Downloaded from: http://www.opencores.org/projects/i2c/ ----
|
---- ----
|
---- ----
|
---------------------------------------------------------------------
|
---------------------------------------------------------------------
|
---- ----
|
---- ----
|
---- Copyright (C) 2000 Richard Herveille ----
|
---- Copyright (C) 2000 Richard Herveille ----
|
---- richard@asics.ws ----
|
---- richard@asics.ws ----
|
---- ----
|
---- ----
|
---- This source file may be used and distributed without ----
|
---- This source file may be used and distributed without ----
|
---- restriction provided that this copyright statement is not ----
|
---- restriction provided that this copyright statement is not ----
|
---- removed from the file and that any derivative work contains ----
|
---- removed from the file and that any derivative work contains ----
|
---- the original copyright notice and the associated disclaimer.----
|
---- the original copyright notice and the associated disclaimer.----
|
---- ----
|
---- ----
|
---- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ----
|
---- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ----
|
---- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ----
|
---- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ----
|
---- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ----
|
---- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ----
|
---- FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ----
|
---- FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ----
|
---- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ----
|
---- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ----
|
---- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ----
|
---- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ----
|
---- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ----
|
---- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ----
|
---- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ----
|
---- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ----
|
---- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ----
|
---- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ----
|
---- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ----
|
---- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ----
|
---- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ----
|
---- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ----
|
---- OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ----
|
---- OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ----
|
---- POSSIBILITY OF SUCH DAMAGE. ----
|
---- POSSIBILITY OF SUCH DAMAGE. ----
|
---- ----
|
---- ----
|
---------------------------------------------------------------------
|
---------------------------------------------------------------------
|
|
|
-- CVS Log
|
-- CVS Log
|
--
|
--
|
-- $Id: i2c_master_top.vhd,v 1.8 2009-01-20 10:38:45 rherveille Exp $
|
-- $Id: i2c_master_top.vhd,v 1.8 2009-01-20 10:38:45 rherveille Exp $
|
--
|
--
|
-- $Date: 2009-01-20 10:38:45 $
|
-- $Date: 2009-01-20 10:38:45 $
|
-- $Revision: 1.8 $
|
-- $Revision: 1.8 $
|
-- $Author: rherveille $
|
-- $Author: rherveille $
|
-- $Locker: $
|
-- $Locker: $
|
-- $State: Exp $
|
-- $State: Exp $
|
--
|
--
|
-- Change History:
|
-- Change History:
|
-- $Log: not supported by cvs2svn $
|
|
-- Revision 1.7 2004/03/14 10:17:03 rherveille
|
-- Revision 1.7 2004/03/14 10:17:03 rherveille
|
-- Fixed simulation issue when writing to CR register
|
-- Fixed simulation issue when writing to CR register
|
--
|
--
|
-- Revision 1.6 2003/08/09 07:01:13 rherveille
|
-- Revision 1.6 2003/08/09 07:01:13 rherveille
|
-- Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
|
-- Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
|
-- Fixed a potential bug in the byte controller's host-acknowledge generation.
|
-- Fixed a potential bug in the byte controller's host-acknowledge generation.
|
--
|
--
|
-- Revision 1.5 2003/02/01 02:03:06 rherveille
|
-- Revision 1.5 2003/02/01 02:03:06 rherveille
|
-- Fixed a few 'arbitration lost' bugs. VHDL version only.
|
-- Fixed a few 'arbitration lost' bugs. VHDL version only.
|
--
|
--
|
-- Revision 1.4 2002/12/26 16:05:47 rherveille
|
-- Revision 1.4 2002/12/26 16:05:47 rherveille
|
-- Core is now a Multimaster I2C controller.
|
-- Core is now a Multimaster I2C controller.
|
--
|
--
|
-- Revision 1.3 2002/11/30 22:24:37 rherveille
|
-- Revision 1.3 2002/11/30 22:24:37 rherveille
|
-- Cleaned up code
|
-- Cleaned up code
|
--
|
--
|
-- Revision 1.2 2001/11/10 10:52:44 rherveille
|
-- Revision 1.2 2001/11/10 10:52:44 rherveille
|
-- Changed PRER reset value from 0x0000 to 0xffff, conform specs.
|
-- Changed PRER reset value from 0x0000 to 0xffff, conform specs.
|
--
|
--
|
|
|
|
|
library ieee;
|
library ieee;
|
use ieee.std_logic_1164.all;
|
use ieee.std_logic_1164.all;
|
use ieee.std_logic_arith.all;
|
|
|
|
entity i2c_master_top is
|
entity i2c_master_top is
|
generic(
|
generic(
|
ARST_LVL : std_logic := '0' -- asynchronous reset level
|
ARST_LVL : std_logic := '0' -- asynchronous reset level
|
);
|
);
|
port (
|
port (
|
-- wishbone signals
|
-- wishbone signals
|
wb_clk_i : in std_logic; -- master clock input
|
wb_clk_i : in std_logic; -- master clock input
|
wb_rst_i : in std_logic := '0'; -- synchronous active high reset
|
wb_rst_i : in std_logic := '0'; -- synchronous active high reset
|
arst_i : in std_logic := not ARST_LVL; -- asynchronous reset
|
arst_i : in std_logic := not ARST_LVL; -- asynchronous reset
|
wb_adr_i : in std_logic_vector(2 downto 0); -- lower address bits
|
wb_adr_i : in std_logic_vector(2 downto 0); -- lower address bits
|
wb_dat_i : in std_logic_vector(7 downto 0); -- Databus input
|
wb_dat_i : in std_logic_vector(7 downto 0); -- Databus input
|
wb_dat_o : out std_logic_vector(7 downto 0); -- Databus output
|
wb_dat_o : out std_logic_vector(7 downto 0); -- Databus output
|
wb_we_i : in std_logic; -- Write enable input
|
wb_we_i : in std_logic; -- Write enable input
|
wb_stb_i : in std_logic; -- Strobe signals / core select signal
|
wb_stb_i : in std_logic; -- Strobe signals / core select signal
|
wb_cyc_i : in std_logic; -- Valid bus cycle input
|
wb_cyc_i : in std_logic; -- Valid bus cycle input
|
wb_ack_o : out std_logic; -- Bus cycle acknowledge output
|
wb_ack_o : out std_logic; -- Bus cycle acknowledge output
|
wb_inta_o : out std_logic; -- interrupt request output signal
|
wb_inta_o : out std_logic; -- interrupt request output signal
|
|
|
-- i2c lines
|
-- i2c lines
|
scl_pad_i : in std_logic; -- i2c clock line input
|
scl_pad_i : in std_logic; -- i2c clock line input
|
scl_pad_o : out std_logic; -- i2c clock line output
|
scl_pad_o : out std_logic; -- i2c clock line output
|
scl_padoen_o : out std_logic; -- i2c clock line output enable, active low
|
scl_padoen_o : out std_logic; -- i2c clock line output enable, active low
|
sda_pad_i : in std_logic; -- i2c data line input
|
sda_pad_i : in std_logic; -- i2c data line input
|
sda_pad_o : out std_logic; -- i2c data line output
|
sda_pad_o : out std_logic; -- i2c data line output
|
sda_padoen_o : out std_logic -- i2c data line output enable, active low
|
sda_padoen_o : out std_logic -- i2c data line output enable, active low
|
);
|
);
|
end entity i2c_master_top;
|
end entity i2c_master_top;
|
|
|
architecture structural of i2c_master_top is
|
architecture structural of i2c_master_top is
|
component i2c_master_byte_ctrl is
|
component i2c_master_byte_ctrl is
|
port (
|
port (
|
clk : in std_logic;
|
clk : in std_logic;
|
rst : in std_logic; -- synchronous active high reset (WISHBONE compatible)
|
rst : in std_logic; -- synchronous active high reset (WISHBONE compatible)
|
nReset : in std_logic; -- asynchornous active low reset (FPGA compatible)
|
nReset : in std_logic; -- asynchornous active low reset (FPGA compatible)
|
ena : in std_logic; -- core enable signal
|
ena : in std_logic; -- core enable signal
|
|
|
clk_cnt : in unsigned(15 downto 0); -- 4x SCL
|
clk_cnt : in unsigned(15 downto 0); -- 4x SCL
|
|
|
-- input signals
|
-- input signals
|
start,
|
start,
|
stop,
|
stop,
|
read,
|
read,
|
write,
|
write,
|
ack_in : std_logic;
|
ack_in : std_logic;
|
din : in std_logic_vector(7 downto 0);
|
din : in std_logic_vector(7 downto 0);
|
|
|
-- output signals
|
-- output signals
|
cmd_ack : out std_logic;
|
cmd_ack : out std_logic;
|
ack_out : out std_logic;
|
ack_out : out std_logic;
|
i2c_busy : out std_logic;
|
i2c_busy : out std_logic;
|
i2c_al : out std_logic;
|
i2c_al : out std_logic;
|
dout : out std_logic_vector(7 downto 0);
|
dout : out std_logic_vector(7 downto 0);
|
|
|
-- i2c lines
|
-- i2c lines
|
scl_i : in std_logic; -- i2c clock line input
|
scl_i : in std_logic; -- i2c clock line input
|
scl_o : out std_logic; -- i2c clock line output
|
scl_o : out std_logic; -- i2c clock line output
|
scl_oen : out std_logic; -- i2c clock line output enable, active low
|
scl_oen : out std_logic; -- i2c clock line output enable, active low
|
sda_i : in std_logic; -- i2c data line input
|
sda_i : in std_logic; -- i2c data line input
|
sda_o : out std_logic; -- i2c data line output
|
sda_o : out std_logic; -- i2c data line output
|
sda_oen : out std_logic -- i2c data line output enable, active low
|
sda_oen : out std_logic -- i2c data line output enable, active low
|
);
|
);
|
end component i2c_master_byte_ctrl;
|
end component i2c_master_byte_ctrl;
|
|
|
-- registers
|
-- registers
|
signal prer : unsigned(15 downto 0); -- clock prescale register
|
signal prer : unsigned(15 downto 0); -- clock prescale register
|
signal ctr : std_logic_vector(7 downto 0); -- control register
|
signal ctr : std_logic_vector(7 downto 0); -- control register
|
signal txr : std_logic_vector(7 downto 0); -- transmit register
|
signal txr : std_logic_vector(7 downto 0); -- transmit register
|
signal rxr : std_logic_vector(7 downto 0); -- receive register
|
signal rxr : std_logic_vector(7 downto 0); -- receive register
|
signal cr : std_logic_vector(7 downto 0); -- command register
|
signal cr : std_logic_vector(7 downto 0); -- command register
|
signal sr : std_logic_vector(7 downto 0); -- status register
|
signal sr : std_logic_vector(7 downto 0); -- status register
|
|
|
-- internal reset signal
|
-- internal reset signal
|
signal rst_i : std_logic;
|
signal rst_i : std_logic;
|
|
|
-- wishbone write access
|
-- wishbone write access
|
signal wb_wacc : std_logic;
|
signal wb_wacc : std_logic;
|
|
|
-- internal acknowledge signal
|
-- internal acknowledge signal
|
signal iack_o : std_logic;
|
signal iack_o : std_logic;
|
|
|
-- done signal: command completed, clear command register
|
-- done signal: command completed, clear command register
|
signal done : std_logic;
|
signal done : std_logic;
|
|
|
-- command register signals
|
-- command register signals
|
signal sta, sto, rd, wr, ack, iack : std_logic;
|
signal sta, sto, rd, wr, ack, iack : std_logic;
|
|
|
signal core_en : std_logic; -- core enable signal
|
signal core_en : std_logic; -- core enable signal
|
signal ien : std_logic; -- interrupt enable signal
|
signal ien : std_logic; -- interrupt enable signal
|
|
|
-- status register signals
|
-- status register signals
|
signal irxack, rxack : std_logic; -- received aknowledge from slave
|
signal irxack, rxack : std_logic; -- received aknowledge from slave
|
signal tip : std_logic; -- transfer in progress
|
signal tip : std_logic; -- transfer in progress
|
signal irq_flag : std_logic; -- interrupt pending flag
|
signal irq_flag : std_logic; -- interrupt pending flag
|
signal i2c_busy : std_logic; -- i2c bus busy (start signal detected)
|
signal i2c_busy : std_logic; -- i2c bus busy (start signal detected)
|
signal i2c_al, al : std_logic; -- arbitration lost
|
signal i2c_al, al : std_logic; -- arbitration lost
|
|
|
begin
|
begin
|
-- generate internal reset signal
|
-- generate internal reset signal
|
rst_i <= arst_i xor ARST_LVL;
|
rst_i <= arst_i xor ARST_LVL;
|
|
|
-- generate acknowledge output signal
|
-- generate acknowledge output signal
|
gen_ack_o : process(wb_clk_i)
|
gen_ack_o : process(wb_clk_i)
|
begin
|
begin
|
if (wb_clk_i'event and wb_clk_i = '1') then
|
if (wb_clk_i'event and wb_clk_i = '1') then
|
iack_o <= wb_cyc_i and wb_stb_i and not iack_o; -- because timing is always honored
|
iack_o <= wb_cyc_i and wb_stb_i and not iack_o; -- because timing is always honored
|
end if;
|
end if;
|
end process gen_ack_o;
|
end process gen_ack_o;
|
wb_ack_o <= iack_o;
|
wb_ack_o <= iack_o;
|
|
|
|
|
-- generate wishbone write access signal
|
-- generate wishbone write access signal
|
wb_wacc <= wb_cyc_i and wb_stb_i and wb_we_i;
|
wb_wacc <= wb_we_i and iack_o;
|
|
|
-- assign wb_dat_o
|
-- assign wb_dat_o
|
assign_dato : process(wb_clk_i)
|
assign_dato : process(wb_clk_i)
|
begin
|
begin
|
if (wb_clk_i'event and wb_clk_i = '1') then
|
if (wb_clk_i'event and wb_clk_i = '1') then
|
case wb_adr_i is
|
case wb_adr_i is
|
when "000" => wb_dat_o <= std_logic_vector(prer( 7 downto 0));
|
when "000" => wb_dat_o <= std_logic_vector(prer( 7 downto 0));
|
when "001" => wb_dat_o <= std_logic_vector(prer(15 downto 8));
|
when "001" => wb_dat_o <= std_logic_vector(prer(15 downto 8));
|
when "010" => wb_dat_o <= ctr;
|
when "010" => wb_dat_o <= ctr;
|
when "011" => wb_dat_o <= rxr; -- write is transmit register TxR
|
when "011" => wb_dat_o <= rxr; -- write is transmit register TxR
|
when "100" => wb_dat_o <= sr; -- write is command register CR
|
when "100" => wb_dat_o <= sr; -- write is command register CR
|
|
|
-- Debugging registers:
|
-- Debugging registers:
|
-- These registers are not documented.
|
-- These registers are not documented.
|
-- Functionality could change in future releases
|
-- Functionality could change in future releases
|
when "101" => wb_dat_o <= txr;
|
when "101" => wb_dat_o <= txr;
|
when "110" => wb_dat_o <= cr;
|
when "110" => wb_dat_o <= cr;
|
when "111" => wb_dat_o <= (others => '0');
|
when "111" => wb_dat_o <= (others => '0');
|
when others => wb_dat_o <= (others => 'X'); -- for simulation only
|
when others => wb_dat_o <= (others => 'X'); -- for simulation only
|
end case;
|
end case;
|
end if;
|
end if;
|
end process assign_dato;
|
end process assign_dato;
|
|
|
|
|
-- generate registers (CR, SR see below)
|
-- generate registers (CR, SR see below)
|
gen_regs: process(rst_i, wb_clk_i)
|
gen_regs: process(rst_i, wb_clk_i)
|
begin
|
begin
|
if (rst_i = '0') then
|
if (rst_i = '0') then
|
prer <= (others => '1');
|
prer <= (others => '1');
|
ctr <= (others => '0');
|
ctr <= (others => '0');
|
txr <= (others => '0');
|
txr <= (others => '0');
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
if (wb_rst_i = '1') then
|
if (wb_rst_i = '1') then
|
prer <= (others => '1');
|
prer <= (others => '1');
|
ctr <= (others => '0');
|
ctr <= (others => '0');
|
txr <= (others => '0');
|
txr <= (others => '0');
|
elsif (wb_wacc = '1') then
|
elsif (wb_wacc = '1') then
|
case wb_adr_i is
|
case wb_adr_i is
|
when "000" => prer( 7 downto 0) <= unsigned(wb_dat_i);
|
when "000" => prer( 7 downto 0) <= unsigned(wb_dat_i);
|
when "001" => prer(15 downto 8) <= unsigned(wb_dat_i);
|
when "001" => prer(15 downto 8) <= unsigned(wb_dat_i);
|
when "010" => ctr <= wb_dat_i;
|
when "010" => ctr <= wb_dat_i;
|
when "011" => txr <= wb_dat_i;
|
when "011" => txr <= wb_dat_i;
|
when "100" => null; --write to CR, avoid executing the others clause
|
when "100" => null; --write to CR, avoid executing the others clause
|
|
|
-- illegal cases, for simulation only
|
-- illegal cases, for simulation only
|
when others =>
|
when others =>
|
report ("Illegal write address, setting all registers to unknown.");
|
report ("Illegal write address, setting all registers to unknown.");
|
prer <= (others => 'X');
|
prer <= (others => 'X');
|
ctr <= (others => 'X');
|
ctr <= (others => 'X');
|
txr <= (others => 'X');
|
txr <= (others => 'X');
|
end case;
|
end case;
|
end if;
|
end if;
|
end if;
|
end if;
|
end process gen_regs;
|
end process gen_regs;
|
|
|
|
|
-- generate command register
|
-- generate command register
|
gen_cr: process(rst_i, wb_clk_i)
|
gen_cr: process(rst_i, wb_clk_i)
|
begin
|
begin
|
if (rst_i = '0') then
|
if (rst_i = '0') then
|
cr <= (others => '0');
|
cr <= (others => '0');
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
if (wb_rst_i = '1') then
|
if (wb_rst_i = '1') then
|
cr <= (others => '0');
|
cr <= (others => '0');
|
elsif (wb_wacc = '1') then
|
elsif (wb_wacc = '1') then
|
if ( (core_en = '1') and (wb_adr_i = "100") ) then
|
if ( (core_en = '1') and (wb_adr_i = "100") ) then
|
-- only take new commands when i2c core enabled
|
-- only take new commands when i2c core enabled
|
-- pending commands are finished
|
-- pending commands are finished
|
cr <= wb_dat_i;
|
cr <= wb_dat_i;
|
end if;
|
end if;
|
else
|
else
|
if (done = '1' or i2c_al = '1') then
|
if (done = '1' or i2c_al = '1') then
|
cr(7 downto 4) <= (others => '0'); -- clear command bits when command done or arbitration lost
|
cr(7 downto 4) <= (others => '0'); -- clear command bits when command done or arbitration lost
|
end if;
|
end if;
|
|
|
cr(2 downto 1) <= (others => '0'); -- reserved bits, always '0'
|
cr(2 downto 1) <= (others => '0'); -- reserved bits, always '0'
|
cr(0) <= '0'; -- clear IRQ_ACK bit
|
cr(0) <= '0'; -- clear IRQ_ACK bit
|
end if;
|
end if;
|
end if;
|
end if;
|
end process gen_cr;
|
end process gen_cr;
|
|
|
-- decode command register
|
-- decode command register
|
sta <= cr(7);
|
sta <= cr(7);
|
sto <= cr(6);
|
sto <= cr(6);
|
rd <= cr(5);
|
rd <= cr(5);
|
wr <= cr(4);
|
wr <= cr(4);
|
ack <= cr(3);
|
ack <= cr(3);
|
iack <= cr(0);
|
iack <= cr(0);
|
|
|
-- decode control register
|
-- decode control register
|
core_en <= ctr(7);
|
core_en <= ctr(7);
|
ien <= ctr(6);
|
ien <= ctr(6);
|
|
|
-- hookup byte controller block
|
-- hookup byte controller block
|
byte_ctrl: i2c_master_byte_ctrl port map (
|
byte_ctrl: i2c_master_byte_ctrl
|
|
port map (
|
clk => wb_clk_i,
|
clk => wb_clk_i,
|
rst => wb_rst_i,
|
rst => wb_rst_i,
|
nReset => rst_i,
|
nReset => rst_i,
|
ena => core_en,
|
ena => core_en,
|
clk_cnt => prer,
|
clk_cnt => prer,
|
start => sta,
|
start => sta,
|
stop => sto,
|
stop => sto,
|
read => rd,
|
read => rd,
|
write => wr,
|
write => wr,
|
ack_in => ack,
|
ack_in => ack,
|
i2c_busy => i2c_busy,
|
i2c_busy => i2c_busy,
|
i2c_al => i2c_al,
|
i2c_al => i2c_al,
|
din => txr,
|
din => txr,
|
cmd_ack => done,
|
cmd_ack => done,
|
ack_out => irxack,
|
ack_out => irxack,
|
dout => rxr,
|
dout => rxr,
|
scl_i => scl_pad_i,
|
scl_i => scl_pad_i,
|
scl_o => scl_pad_o,
|
scl_o => scl_pad_o,
|
scl_oen => scl_padoen_o,
|
scl_oen => scl_padoen_o,
|
sda_i => sda_pad_i,
|
sda_i => sda_pad_i,
|
sda_o => sda_pad_o,
|
sda_o => sda_pad_o,
|
sda_oen => sda_padoen_o
|
sda_oen => sda_padoen_o
|
);
|
);
|
|
|
|
|
-- status register block + interrupt request signal
|
-- status register block + interrupt request signal
|
st_irq_block : block
|
st_irq_block : block
|
begin
|
begin
|
-- generate status register bits
|
-- generate status register bits
|
gen_sr_bits: process (wb_clk_i, rst_i)
|
gen_sr_bits: process (wb_clk_i, rst_i)
|
begin
|
begin
|
if (rst_i = '0') then
|
if (rst_i = '0') then
|
al <= '0';
|
al <= '0';
|
rxack <= '0';
|
rxack <= '0';
|
tip <= '0';
|
tip <= '0';
|
irq_flag <= '0';
|
irq_flag <= '0';
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
if (wb_rst_i = '1') then
|
if (wb_rst_i = '1') then
|
al <= '0';
|
al <= '0';
|
rxack <= '0';
|
rxack <= '0';
|
tip <= '0';
|
tip <= '0';
|
irq_flag <= '0';
|
irq_flag <= '0';
|
else
|
else
|
al <= i2c_al or (al and not sta);
|
al <= i2c_al or (al and not sta);
|
rxack <= irxack;
|
rxack <= irxack;
|
tip <= (rd or wr);
|
tip <= (rd or wr);
|
|
|
-- interrupt request flag is always generated
|
-- interrupt request flag is always generated
|
irq_flag <= (done or i2c_al or irq_flag) and not iack;
|
irq_flag <= (done or i2c_al or irq_flag) and not iack;
|
end if;
|
end if;
|
end if;
|
end if;
|
end process gen_sr_bits;
|
end process gen_sr_bits;
|
|
|
-- generate interrupt request signals
|
-- generate interrupt request signals
|
gen_irq: process (wb_clk_i, rst_i)
|
gen_irq: process (wb_clk_i, rst_i)
|
begin
|
begin
|
if (rst_i = '0') then
|
if (rst_i = '0') then
|
wb_inta_o <= '0';
|
wb_inta_o <= '0';
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
elsif (wb_clk_i'event and wb_clk_i = '1') then
|
if (wb_rst_i = '1') then
|
if (wb_rst_i = '1') then
|
wb_inta_o <= '0';
|
wb_inta_o <= '0';
|
else
|
else
|
-- interrupt signal is only generated when IEN (interrupt enable bit) is set
|
-- interrupt signal is only generated when IEN (interrupt enable bit) is set
|
wb_inta_o <= irq_flag and ien;
|
wb_inta_o <= irq_flag and ien;
|
end if;
|
end if;
|
end if;
|
end if;
|
end process gen_irq;
|
end process gen_irq;
|
|
|
-- assign status register bits
|
-- assign status register bits
|
sr(7) <= rxack;
|
sr(7) <= rxack;
|
sr(6) <= i2c_busy;
|
sr(6) <= i2c_busy;
|
sr(5) <= al;
|
sr(5) <= al;
|
sr(4 downto 2) <= (others => '0'); -- reserved
|
sr(4 downto 2) <= (others => '0'); -- reserved
|
sr(1) <= tip;
|
sr(1) <= tip;
|
sr(0) <= irq_flag;
|
sr(0) <= irq_flag;
|
end block;
|
end block;
|
|
|
end architecture structural;
|
end architecture structural;
|
|
|
