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[/] [open8_urisc/] [trunk/] [VHDL/] [o8_ltc2355_2p.vhd] - Rev 194
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-- Copyright (c)2013, 2020 Jeremy Seth Henry -- All rights reserved. -- -- 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, -- where applicable (as part of a user interface, debugging port, etc.) -- -- THIS SOFTWARE IS PROVIDED BY JEREMY SETH HENRY ``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 JEREMY SETH HENRY 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. -- -- VHDL units : ltc2355_2p -- Description: Reads out a pair of LTC2355 14-bit ADCs which are wired with -- : common clock and CONVERT START inputs. Because they are -- : synchronized, this entity provides simultaneously updated -- : parallel data buses. -- -- Notes : Depends on the fact that the two LTC2355 converters are wired -- : with their SCLK and CONV lines tied together, and DATA1 and -- : DATA2 independently routed to separate I/O pins. library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_unsigned.all; use ieee.std_logic_arith.all; use ieee.std_logic_misc.all; library work; use work.open8_pkg.all; entity o8_ltc2355_2p is generic( Address : ADDRESS_TYPE; Reset_Level : std_logic; Sys_Freq : real ); port( Clock : in std_logic; -- 96MHz MAX for proper operation Reset : in std_logic; uSec_Tick : in std_logic; -- Client IF Bus_Address : in ADDRESS_TYPE; Wr_Enable : in std_logic; Wr_Data : in DATA_TYPE; Rd_Enable : in std_logic; Rd_Data : out DATA_TYPE; Interrupt : out std_logic; -- ADC IF ADC_SCLK : out std_logic; ADC_CONV : out std_logic; ADC_DATA1 : in std_logic; ADC_DATA2 : in std_logic ); end entity; architecture behave of o8_ltc2355_2p is constant Divide_SCLK_by_2 : boolean := (Sys_Freq > 96000000.0); constant User_Addr : std_logic_vector(15 downto 3) := Address(15 downto 3); alias Comp_Addr is Bus_Address(15 downto 3); alias Reg_Sel is Bus_Address(2 downto 0); signal Reg_Sel_q : std_logic_vector(2 downto 0); signal Wr_Data_q : DATA_TYPE; signal Addr_Match : std_logic; signal Wr_En : std_logic; signal Rd_En : std_logic; signal User_In : DATA_TYPE; signal User_Trig : std_logic; signal Timer_Int : DATA_TYPE; signal Timer_Cnt : DATA_TYPE; signal Timer_Trig : std_logic; type ADC_STATES is ( IDLE, START, CLK_HIGH, CLK_HIGH2, CLK_LOW, CLK_LOW2, UPDATE ); signal ad_state : ADC_STATES; signal rx_buffer1 : std_logic_vector(16 downto 0); signal rx_buffer2 : std_logic_vector(16 downto 0); signal bit_cntr : std_logic_vector(4 downto 0); constant BIT_COUNT : std_logic_vector(4 downto 0) := conv_std_logic_vector(16,5); signal ADC1_Data : std_logic_vector(13 downto 0); signal ADC2_Data : std_logic_vector(13 downto 0); signal ADC_Ready : std_logic; begin Addr_Match <= '1' when Comp_Addr = User_Addr else '0'; io_reg: process( Clock, Reset ) begin if( Reset = Reset_Level )then Reg_Sel_q <= (others => '0'); Wr_Data_q <= x"00"; Wr_En <= '0'; Rd_En <= '0'; Rd_Data <= OPEN8_NULLBUS; User_Trig <= '0'; Timer_Int <= x"00"; elsif( rising_edge( Clock ) )then Reg_Sel_q <= Reg_Sel; Wr_Data_q <= Wr_Data; Wr_En <= Wr_Enable and Addr_Match; User_Trig <= '0'; if( Wr_En = '1' )then if( Reg_Sel_q = "110" )then Timer_Int <= Wr_Data_q; end if; if( Reg_Sel_q = "111" )then User_Trig <= '1'; end if; end if; Rd_En <= Rd_Enable and Addr_Match; Rd_Data <= OPEN8_NULLBUS; if( Rd_En = '1' )then case( Reg_Sel_q )is -- Channel 1, Full resolution, lower byte when "000" => Rd_Data <= ADC1_Data(7 downto 0); -- Channel 1, Full resolution, upper byte when "001" => Rd_Data <= "00" & ADC1_Data(13 downto 8); -- Channel 2, Full resolution, lower byte when "010" => Rd_Data <= ADC2_Data(7 downto 0); -- Channel 2, Full resolution, upper byte when "011" => Rd_Data <= "00" & ADC2_Data(13 downto 8); -- Channel 1, 8-bit resolution when "100" => Rd_Data <= ADC1_Data(13 downto 6); -- Channel 2, 8-bit resolution when "101" => Rd_Data <= ADC2_Data(13 downto 6); -- Self-update rate when "110" => Rd_Data <= Timer_Int; -- Interface status when "111" => Rd_Data(7) <= ADC_Ready; when others => null; end case; end if; end if; end process; Interval_proc: process( Clock, Reset ) begin if( Reset = Reset_Level )then Timer_Cnt <= x"00"; Timer_Trig <= '0'; elsif( rising_edge(Clock) )then Timer_Trig <= '0'; Timer_Cnt <= Timer_Cnt - uSec_Tick; if( or_reduce(Timer_Cnt) = '0' )then Timer_Cnt <= Timer_Int; Timer_Trig <= or_reduce(Timer_Int); -- Only issue output on Int > 0 end if; end if; end process; ADC_IO_FSM: process( Clock, Reset ) begin if( Reset = Reset_Level )then ad_state <= IDLE; ADC_Ready <= '0'; rx_buffer1 <= (others => '0'); rx_buffer2 <= (others => '0'); bit_cntr <= (others => '0'); ADC1_Data <= (others => '0'); ADC2_Data <= (others => '0'); ADC_SCLK <= '1'; ADC_CONV <= '0'; Interrupt <= '0'; elsif( rising_edge(Clock) )then ADC_Ready <= '0'; ADC_SCLK <= '1'; ADC_CONV <= '0'; Interrupt <= '0'; case( ad_state )is when IDLE => ADC_Ready <= '1'; if( (User_Trig or Timer_Trig) = '1' )then ad_state <= START; end if; when START => ADC_SCLK <= '0'; ADC_CONV <= '1'; bit_cntr <= BIT_COUNT; ad_state <= CLK_HIGH; when CLK_HIGH => ad_state <= CLK_LOW; if( Divide_SCLK_by_2 )then ad_state <= CLK_HIGH2; end if; when CLK_HIGH2 => ad_state <= CLK_LOW; when CLK_LOW => ADC_SCLK <= '0'; rx_buffer1(conv_integer(bit_cntr)) <= ADC_DATA1; rx_buffer2(conv_integer(bit_cntr)) <= ADC_DATA2; bit_cntr <= bit_cntr - 1; ad_state <= CLK_HIGH; if( bit_cntr = 0 )then ad_state <= UPDATE; elsif( Divide_SCLK_by_2 )then ad_state <= CLK_LOW2; end if; when CLK_LOW2 => ADC_SCLK <= '0'; ad_state <= CLK_HIGH; when UPDATE => ADC_SCLK <= '0'; ad_state <= IDLE; ADC1_Data <= rx_buffer1(14 downto 1); ADC2_Data <= rx_buffer2(14 downto 1); Interrupt <= '1'; when others => null; end case; end if; end process; end architecture;
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