📄 picoblaze_dac_control.vhd
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--
-- KCPSM3 reference design - PicoBlaze driving the four channel D/A converter
-- type LTC2624 from Linear Technology.
--
-- Design provided and tested on the Spartan-3E Starter Kit (Revision C)
--
-- Ken Chapman - Xilinx Ltd - 24th November 2005
-- Revised : 21st February 2006
--
-- The JTAG loader utility is also available for rapid program development.
--
-- The design is set up for a 50MHz system clock.
-- The simple LEDs and J4 connector are utilised for development and monitoring.
-- The switches and press buttons are connected just for fun!
--
------------------------------------------------------------------------------------
--
-- NOTICE:
--
-- Copyright Xilinx, Inc. 2006. This code may be contain portions patented by other
-- third parties. By providing this core as one possible implementation of a standard,
-- Xilinx is making no representation that the provided implementation of this standard
-- is free from any claims of infringement by any third party. Xilinx expressly
-- disclaims any warranty with respect to the adequacy of the implementation, including
-- but not limited to any warranty or representation that the implementation is free
-- from claims of any third party. Furthermore, Xilinx is providing this core as a
-- courtesy to you and suggests that you contact all third parties to obtain the
-- necessary rights to use this implementation.
--
------------------------------------------------------------------------------------
--
-- Library declarations
--
-- Standard IEEE libraries
--
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
--
------------------------------------------------------------------------------------
--
--
entity picoblaze_dac_control is
Port ( spi_sck : out std_logic;
spi_sdo : in std_logic;
spi_sdi : out std_logic;
spi_rom_cs : out std_logic;
spi_amp_cs : out std_logic;
spi_adc_conv : out std_logic;
spi_dac_cs : out std_logic;
spi_amp_shdn : out std_logic;
spi_amp_sdo : in std_logic;
spi_dac_clr : out std_logic;
strataflash_oe : out std_logic;
strataflash_ce : out std_logic;
strataflash_we : out std_logic;
platformflash_oe : out std_logic;
simple_io : out std_logic_vector(12 downto 9);
led : out std_logic_vector(7 downto 0);
switch : in std_logic_vector(3 downto 0);
btn_north : in std_logic;
btn_east : in std_logic;
btn_south : in std_logic;
btn_west : in std_logic;
clk : in std_logic);
end picoblaze_dac_control;
--
------------------------------------------------------------------------------------
--
-- Start of test architecture
--
architecture Behavioral of picoblaze_dac_control is
--
------------------------------------------------------------------------------------
--
-- declaration of KCPSM3
--
component kcpsm3
Port ( address : out std_logic_vector(9 downto 0);
instruction : in std_logic_vector(17 downto 0);
port_id : out std_logic_vector(7 downto 0);
write_strobe : out std_logic;
out_port : out std_logic_vector(7 downto 0);
read_strobe : out std_logic;
in_port : in std_logic_vector(7 downto 0);
interrupt : in std_logic;
interrupt_ack : out std_logic;
reset : in std_logic;
clk : in std_logic);
end component;
--
-- declaration of program ROM
--
component dac_ctrl
Port ( address : in std_logic_vector(9 downto 0);
instruction : out std_logic_vector(17 downto 0);
proc_reset : out std_logic; --JTAG Loader version
clk : in std_logic);
end component;
--
------------------------------------------------------------------------------------
--
-- Signals used to connect KCPSM3 to program ROM and I/O logic
--
signal address : std_logic_vector(9 downto 0);
signal instruction : std_logic_vector(17 downto 0);
signal port_id : std_logic_vector(7 downto 0);
signal out_port : std_logic_vector(7 downto 0);
signal in_port : std_logic_vector(7 downto 0);
signal write_strobe : std_logic;
signal read_strobe : std_logic;
signal interrupt : std_logic :='0';
signal interrupt_ack : std_logic;
signal kcpsm3_reset : std_logic;
--
--
-- Signals used to generate interrupt
--
signal int_count : integer range 0 to 6249 :=0;
signal event_8khz : std_logic;
--
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
--
-- Start of circuit description
--
begin
--
simple_io(12) <= clk; --Test point
--
----------------------------------------------------------------------------------------------------------------------------------
-- Disable unused components
----------------------------------------------------------------------------------------------------------------------------------
--
--StrataFLASH must be disabled to prevent it driving the SDI line with its D0 output
--or conflicting with the LCD display
--
strataflash_oe <= '1';
strataflash_ce <= '1';
strataflash_we <= '1';
--
--Platform FLASH must be disabled to prevent it driving the SDI line with its D0 output.
--Since the CE is via the 9500 device, the OE/RESET is the easier direct control (OE active high).
--
platformflash_oe <= '0';
--
--
----------------------------------------------------------------------------------------------------------------------------------
-- KCPSM3 and the program memory
----------------------------------------------------------------------------------------------------------------------------------
--
processor: kcpsm3
port map( address => address,
instruction => instruction,
port_id => port_id,
write_strobe => write_strobe,
out_port => out_port,
read_strobe => read_strobe,
in_port => in_port,
interrupt => interrupt,
interrupt_ack => interrupt_ack,
reset => kcpsm3_reset,
clk => clk);
program_rom: dac_ctrl
port map( address => address,
instruction => instruction,
proc_reset => kcpsm3_reset,
clk => clk);
--
----------------------------------------------------------------------------------------------------------------------------------
-- Interrupt
----------------------------------------------------------------------------------------------------------------------------------
--
--
-- Interrupt is used to set an 8KHz sample rate which is typical of audio telecommunication
-- applications. Having a fixed time base also means that all waveform generation by PicoBlaze
-- can be made predictable.
--
-- A simple binary counter is used to divide the 50MHz system clock and provide interrupt pulses.
--
interrupt_control: process(clk)
begin
if clk'event and clk='1' then
--divide 50MHz by 6250 to form 8KHz pulses
if int_count=6249 then
int_count <= 0;
event_8khz <= '1';
else
int_count <= int_count + 1;
event_8khz <= '0';
end if;
-- processor interrupt waits for an acknowledgement
if interrupt_ack='1' then
interrupt <= '0';
elsif event_8khz='1' then
interrupt <= '1';
else
interrupt <= interrupt;
end if;
end if;
end process interrupt_control;
simple_io(9) <= event_8khz; --Test point
simple_io(10) <= interrupt; --Test point
--
----------------------------------------------------------------------------------------------------------------------------------
-- KCPSM3 input ports
----------------------------------------------------------------------------------------------------------------------------------
--
--
-- The inputs connect via a pipelined multiplexer
--
input_ports: process(clk)
begin
if clk'event and clk='1' then
case port_id(0) is
-- read simple toggle switches and buttons at address 00 hex
when '0' => in_port <= switch & btn_west & btn_south & btn_east & btn_north;
-- read SPI data input SDO at address 01 hex
-- called SDO because it connects to the data outputs of all the slave devices
-- Normal SDO data is bit7.
-- SDI data from the amplifier is at bit 6 because it is always driving and needs a separate pin.
when '1' => in_port <= spi_sdo & spi_amp_sdo & "000000";
-- Don't care used for all other addresses to ensure minimum logic implementation
when others => in_port <= "XXXXXXXX";
end case;
end if;
end process input_ports;
--
----------------------------------------------------------------------------------------------------------------------------------
-- KCPSM3 output ports
----------------------------------------------------------------------------------------------------------------------------------
--
-- adding the output registers to the processor
output_ports: process(clk)
begin
if clk'event and clk='1' then
if write_strobe='1' then
-- Write to LEDs at address 80 hex.
if port_id(7)='1' then
led <= out_port;
end if;
-- Write to SPI data output at address 04 hex.
-- called SDI because it connects to the data inputs of all the slave devices
if port_id(2)='1' then
spi_sdi <= out_port(7);
end if;
-- Write to SPI control at address 08 hex.
if port_id(3)='1' then
spi_sck <= out_port(0);
spi_rom_cs <= out_port(1);
--spare control <= out_port(2);
spi_amp_cs <= out_port(3);
spi_adc_conv <= out_port(4);
spi_dac_cs <= out_port(5);
spi_amp_shdn <= out_port(6);
spi_dac_clr <= out_port(7);
simple_io(11) <= out_port(5); --Test point is copy of dac_cs
end if;
end if;
end if;
end process output_ports;
--
----------------------------------------------------------------------------------------------------------------------------------
end Behavioral;
------------------------------------------------------------------------------------------------------------------------------------
--
-- END OF FILE picoblaze_dac_control.vhd
--
------------------------------------------------------------------------------------------------------------------------------------
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