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ibm2030.IBM2030/panel_Switches.vhd

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---------------------------------------------------------------------------
-- Copyright © 2015 Lawrence Wilkinson lawrence@ljw.me.uk
--
-- This file is part of LJW2030, a VHDL implementation of the IBM
-- System/360 Model 30.
--
-- LJW2030 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 3 of the License, or
-- (at your option) any later version.
--
-- LJW2030 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 LJW2030 . If not, see <http://www.gnu.org/licenses/>.
--
---------------------------------------------------------------------------
--
-- File: panel_Switches.vhd
-- Creation Date: 13:26:00 25/11/2015
-- Description:
-- 360/30 Front Panel Switch reading and status LED drivers
-- This reads all the front panel rotary and pushbutton switches
-- and also drives the 5 status LEDs at the lower-right
-- A Maxim MAX7318 device is used to scan (3 outputs) and read (8 inputs)
-- the switches, and also to drive the LEDs (5 outputs)
--
-- Revision History:
--
--
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;
---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;
entity panel_Switches is
Generic (
Clock_divider : integer := 9; -- Fastest allowed is 1.4MHz / 36 for 50MHz clk
Read_delay : integer := 700; -- Number of divided clocks to wait between scan drive and switch read
Number_Switches : integer := 64;
Number_LEDs : integer := 5;
MAX7318_address : std_logic_vector(6 downto 0) := "1000000"
);
Port ( -- Lamp input vector
LEDs : in std_logic_vector(0 to Number_LEDs-1);
-- Switch output vector
Switches : out std_logic_vector(0 to Number_Switches-1);
-- Other inputs
clk : in STD_LOGIC; -- 50MHz default
reset : in STD_LOGIC := '0';
-- Driver outputs
SCL : out std_logic;
SDA : inout std_logic
);
end panel_Switches;
architecture Behavioral of panel_Switches is
signal clk_out : std_logic := '0';
signal MAX7318_SCL, new_MAX7318_SCL, MAX7318_SDA, new_MAX7318_SDA : std_logic := '1';
type SPI_state_type is (idle_h,start_h,start_hl,data_l,data_lh,data_hl,ack_l,ack_l2,ack_lh,ack_h,ack_hl,stop_l,stop_lh,stop_h, stop_h2);
signal SPI_state, new_SPI_state : SPI_state_type := idle_h;
type MAX7318_state_type is (idle,writing45,writing67,writing2,delay,reading1);
signal MAX7318_state, new_MAX7318_state : MAX7318_state_type := idle;
signal bit_counter, new_bit_counter : integer range 0 to 8;
signal byteCount, new_byteCount : integer range 0 to 4;
signal delayCounter, new_delayCounter : integer range 0 to 50000;
constant top_data_out_bit : integer := 31;
signal dataOut, new_dataOut : std_logic_vector(top_data_out_bit downto 0);
signal dataIn, new_dataIn : std_logic_vector(7 downto 0);
signal writeByte, new_writeByte : std_logic_vector(3 downto 0);
signal switchBank, new_switchBank : std_logic_vector(2 downto 0) := "000";
type switchArrayType is array(0 to (Number_Switches+7)/8-1) of std_logic_vector(7 downto 0);
signal switchVector, new_switchVector : switchArrayType := (others=>"00000000");
-- MAX7318 stream is: start, address(7), r/w(1),
-- Address is 0x40 (AD0,1,2=0)
-- Registers are:
-- 00 Input 1 Unused
-- 01 Input 2 Scan inputs
-- 02 Output 1 0,1,2=Scan outputs 3,4,5,6,7=LEDs
-- 03 Output 2 Unused
-- 04 Port 1 Invert 1=Invert 00
-- 05 Port 2 Invert 1=Invert 00
-- 06 Port 1 Config 1=Input 00
-- 07 Port 2 Config 1=Input FF
-- FSM sequence is:
-- Write 04,05: Write Command=4, Register4, Register5
-- Write 06,07: Write Command=6, Register6, Register7
-- Write 02, Wait 1ms, Read 01: Write Command=2, Register2, Wait, Write Command=1, Read Register1
begin
gen_clk : process (clk) is
variable divider : integer := Clock_divider;
begin
if rising_edge(clk) then
if (divider=0) then
divider := Clock_divider;
clk_out <= not clk_out;
else
divider := divider - 1;
end if;
end if;
end process;
max7318 : process (clk_out) is
begin
if rising_edge(clk_out) then
new_bit_counter <= bit_counter;
new_byteCount <= byteCount;
new_SPI_state <= SPI_state;
new_MAX7318_state <= MAX7318_state;
new_delayCounter <= delayCounter;
new_dataOut <= dataOut;
new_dataIn <= dataIn;
new_writeByte <= writeByte;
new_switchBank <= switchBank;
new_switchVector <= switchVector;
case (SPI_state) is
when idle_h =>
new_MAX7318_SDA <= '1';
new_MAX7318_SCL <= '1';
when start_h =>
new_MAX7318_SDA <= '0';
new_MAX7318_SCL <= '1';
new_SPI_state <= start_hl;
when start_hl =>
-- Min 600ns (tSU STA)
new_MAX7318_SDA <= '0';
new_MAX7318_SCL <= '0';
new_SPI_state <= data_l;
new_bit_counter <= 7;
when data_l =>
-- Min 1300ns including data_lh state (tLOW)
if (writeByte(3)='0') then
new_MAX7318_SDA <= dataOut(top_data_out_bit);
new_dataOut <= dataOut(top_data_out_bit-1 downto 0) & '0';
else
new_MAX7318_SDA <= '1';
new_dataIn <= dataIn(6 downto 0) & MAX7318_SDA;
end if;
new_SPI_state <= data_lh;
when data_lh =>
-- Min 100ns (tSU DAT)
new_MAX7318_SCL <= '1';
new_SPI_state <= data_hl;
when data_hl =>
-- Min 700ns (tHIGH)
new_MAX7318_SCL <= '0';
if (bit_counter = 0) then
new_SPI_state <= ack_l;
else
new_bit_counter <= bit_counter - 1;
new_SPI_state <= data_l;
end if;
when ack_l =>
-- Min 1300ns including ack_lh (tLOW)
new_MAX7318_SCL <= '0';
new_SPI_state <= ack_l2;
when ack_l2 =>
if (writeByte(3)='1') then
new_MAX7318_SDA <= '0';
else
new_MAX7318_SDA <= '1';
end if;
new_SPI_state <= ack_lh;
when ack_lh =>
-- Min 300ns (tHD DAT)
new_MAX7318_SCL <= '1';
new_SPI_state <= ack_h;
when ack_h =>
-- Min 700ns (tHIGH)
if (writeByte(3)='0') then
if (MAX7318_SDA = '0') then
-- Ok
new_SPI_state <= ack_hl;
else
-- Error
new_SPI_state <= ack_hl;
end if;
else
new_MAX7318_SDA <= '0';
new_SPI_state <= ack_hl;
end if;
when ack_hl =>
-- Min 300ns (tHD DAT)
new_MAX7318_SCL <= '0';
if (byteCount = 1) then
-- new_MAX7318_SDA <= '0';
new_SPI_state <= stop_l;
else
new_SPI_state <= data_l;
new_byteCount <= byteCount - 1;
new_writeByte <= writeByte(2 downto 0) & "0";
new_bit_counter <= 7;
end if;
when stop_l =>
new_MAX7318_SDA <= '0';
new_SPI_state <= stop_lh;
when stop_lh =>
-- new_MAX7318_SDA <= '0';
new_MAX7318_SCL <= '1';
new_SPI_state <= stop_h;
when stop_h =>
-- Min 600ns (tSU STO)
new_MAX7318_SDA <= '1';
new_MAX7318_SCL <= '1';
new_SPI_state <= stop_h2;
when stop_h2 =>
-- Min 1300ns including idle_h (tBUF)
new_SPI_state <= idle_h;
end case;
case MAX7318_state is
when idle =>
if (SPI_state = idle_h) then
new_dataOut <= MAX7318_address & "0" & "00000100" & "00000000" & "00000000"; -- 4,5 = 00,00
new_writeByte <= "0000";
new_byteCount <= 4;
new_SPI_state <= start_h;
new_MAX7318_state <= writing45;
end if;
when writing45 =>
if (SPI_state = idle_h) then
new_dataOut <= MAX7318_address & "0" & "00000110" & "00000000" & "11111111"; -- 6,7 = 00,FF
new_writeByte <= "0000";
new_byteCount <= 4;
new_SPI_state <= start_h;
new_MAX7318_state <= writing67;
end if;
when writing67 =>
if (SPI_state = idle_h) then
new_dataOut <= MAX7318_address & "0" & "00000010" & LEDs & switchBank & "00000000"; -- 2 = LLLLLSSS
new_writeByte <= "0000";
new_byteCount <= 3;
new_SPI_state <= start_h;
new_MAX7318_state <= writing2;
end if;
when writing2 =>
if (SPI_state = idle_h) then
new_delayCounter <= Read_delay;
new_MAX7318_state <= delay;
end if;
when delay =>
if (delayCounter = 0) then
new_dataOut <= MAX7318_address & "1" & "00000001" & "11111111" & "00000000"; -- 1 = RRRRRRRR
new_writeByte <= "0010";
new_byteCount <= 3;
new_SPI_state <= start_h;
new_MAX7318_state <= reading1;
else
new_delayCounter <= delayCounter - 1;
end if;
when reading1 =>
if (SPI_state = idle_h) then
new_switchVector(to_integer(unsigned(switchBank))) <= dataIn(7 downto 0);
new_switchBank <= std_logic_vector(unsigned(switchBank) + 1);
new_MAX7318_state <= idle;
end if;
end case;
-- State variable updates
MAX7318_SCL <= new_MAX7318_SCL;
MAX7318_SDA <= new_MAX7318_SDA;
bit_counter <= new_bit_counter;
byteCount <= new_byteCount;
if (reset='0') then
SPI_state <= new_SPI_state;
MAX7318_state <= new_MAX7318_state;
else
SPI_state <= idle_h;
MAX7318_state <= idle;
end if;
delayCounter <= new_delayCounter;
dataOut <= new_dataOut;
dataIn <= new_dataIn;
writeByte <= new_writeByte;
switchBank <= new_SwitchBank;
switchVector <= new_SwitchVector;
-- Outputs
switches <= switchVector(0) & switchVector(1) & switchVector(2) & switchVector(3) & switchVector(4) & switchVector(5) & switchVector(6) & switchVector(7);
SCL <= MAX7318_SCL;
SDA <= MAX7318_SDA;
end if;
end process;
end behavioral;
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