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microwatt/fpga/arty-lcd-ts.vhdl

332 lines
13 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library unisim;
use unisim.vcomponents.all;
library work;
use work.wishbone_types.all;
-- Interface for LCD/touchscreen connected to Arduino-compatible socket on Arty A7
entity lcd_touchscreen is
port (
clk : in std_ulogic;
rst : in std_ulogic;
wb_in : in wb_io_master_out;
wb_out : out wb_io_slave_out;
wb_sel : in std_ulogic;
tp : out std_ulogic;
lcd_din : in std_ulogic_vector(7 downto 0);
lcd_dout : out std_ulogic_vector(7 downto 0);
lcd_doe : out std_ulogic;
lcd_doe0 : out std_ulogic;
lcd_doe1 : out std_ulogic;
lcd_rd : out std_ulogic; -- note active low
lcd_wr : out std_ulogic; -- note active low
lcd_rs : out std_ulogic;
lcd_rsoe : out std_ulogic;
lcd_cs : out std_ulogic; -- note active low
lcd_csoe : out std_ulogic;
lcd_rst : out std_ulogic; -- note active low
-- Differential analog inputs from touchscreen
a2_p : in std_ulogic;
a2_n : in std_ulogic;
a3_p : in std_ulogic;
a3_n : in std_ulogic;
a4_p : in std_ulogic;
a4_n : in std_ulogic;
a5_p : in std_ulogic;
a5_n : in std_ulogic
);
end entity lcd_touchscreen;
architecture rtl of lcd_touchscreen is
type state_t is (idle, prep1, prep2, writing, wr_pause, reading, rd_recovery,
drp_lo, drp_hi);
signal state : state_t;
signal delay : unsigned(5 downto 0);
signal ack : std_ulogic;
signal idle1 : std_ulogic;
signal idle2 : std_ulogic;
signal rs : std_ulogic;
signal rsoe : std_ulogic;
signal cs : std_ulogic;
signal csoe : std_ulogic;
signal d0 : std_ulogic;
signal doe0 : std_ulogic;
signal doe1 : std_ulogic;
signal d1 : std_ulogic;
signal tsctrl : std_ulogic;
signal wr_data : std_ulogic_vector(31 downto 0);
signal rd_data : std_ulogic_vector(31 downto 0);
signal wr_sel : std_ulogic_vector(3 downto 0);
signal req_wr : std_ulogic;
signal xadc_di : std_ulogic_vector(15 downto 0);
signal xadc_do : std_ulogic_vector(15 downto 0);
signal xadc_addr : std_ulogic_vector(6 downto 0);
signal xadc_en : std_ulogic;
signal xadc_we : std_ulogic;
signal xadc_rdy : std_ulogic;
signal xadc_eoc : std_ulogic;
signal xadc_eos : std_ulogic;
signal xadc_busy : std_ulogic;
signal eoc_stat : std_ulogic;
signal eos_stat : std_ulogic;
-- Assume touchscreen is connected to the A2 - A5 analog inputs
begin
-- The connection of the analog A0 - A5 pins on the Arty
-- to FPGA pins is as follows:
-- A0 connects to AD4P/AD4N
-- A1 connects to AD5P/AD5N
-- A2 connects to AD6P/AD6N
-- A3 connects to AD7P/AD7N
-- A4 connects to AD15P/AD15N
-- A5 connects to AD0P/AD0N
xadc_0 : XADC
generic map (
init_42 => x"0400" -- adcclk = dclk / 4, i.e. 25MHz
)
port map (
di => xadc_di,
do => xadc_do,
daddr => xadc_addr,
den => xadc_en,
dwe => xadc_we,
dclk => clk,
drdy => xadc_rdy,
reset => rst,
convst => '0',
convstclk => '0',
vp => '0',
vn => '0',
vauxp => a4_p & "0000000" & a3_p & a2_p & "00000" & a5_p,
vauxn => a4_n & "0000000" & a3_n & a2_n & "00000" & a5_n,
eoc => xadc_eoc,
eos => xadc_eos,
busy => xadc_busy
);
-- for now; should make sure it is at least 10us wide
lcd_rst <= not rst;
wb_out.dat <= rd_data;
wb_out.ack <= ack;
wb_out.stall <= '0' when state = idle else '1';
lcd_doe0 <= doe0;
lcd_doe1 <= doe1;
lcd_rs <= rs;
lcd_rsoe <= rsoe;
lcd_cs <= cs;
lcd_csoe <= csoe;
tp <= tsctrl;
process (clk)
variable rdat : std_ulogic_vector(7 downto 0);
begin
if rising_edge(clk) then
ack <= '0';
xadc_en <= '0';
idle2 <= idle1;
if xadc_eoc = '1' then
eoc_stat <= '1';
end if;
if xadc_eos = '1' then
eos_stat <= '1';
end if;
if rst = '1' then
state <= idle;
delay <= to_unsigned(0, 6);
rd_data <= (others => '0');
lcd_rd <= '1';
lcd_wr <= '1';
cs <= '1';
csoe <= '1';
rs <= '0';
rsoe <= '1';
lcd_doe <= '0';
doe0 <= '0';
doe1 <= '0';
d0 <= '0';
d1 <= '0';
idle1 <= '0';
idle2 <= '0';
tsctrl <= '0';
xadc_en <= '0';
eoc_stat <= '0';
eos_stat <= '0';
elsif delay /= "000000" then
delay <= delay - 1;
else
case state is
when idle =>
req_wr <= wb_in.we;
wr_data <= wb_in.dat;
wr_sel <= wb_in.sel;
if idle2 = '1' then
-- delay this one cycle after entering idle
lcd_doe <= '0';
doe0 <= '0';
doe1 <= '0';
end if;
idle1 <= '0';
if wb_in.cyc = '1' and wb_in.stb = '1' and wb_sel = '1' then
if wb_in.sel = "0000" then
ack <= '1';
elsif wb_in.adr(6) = '0' then
if wb_in.we = '1' or wb_in.adr(2) = '1' then
ack <= '1';
end if;
if wb_in.adr(2) = '0' then
-- c8050000 or 8, access LCD controller chip
tsctrl <= '0';
csoe <= '1';
cs <= '0'; -- active low
rsoe <= '1';
rs <= wb_in.adr(1);
doe0 <= '0';
doe1 <= '0';
state <= prep1;
elsif wb_in.adr(1) = '0' then
-- c8050010, touchscreen drive register
tsctrl <= '1';
idle2 <= '0';
rdat := rsoe & rs & doe0 & d0 & doe1 & d1 & csoe & cs;
rd_data <= rdat & rdat & rdat & rdat;
if wb_in.we = '1' and wb_in.sel(0) = '1' then
rsoe <= wb_in.dat(7);
rs <= wb_in.dat(6);
doe0 <= wb_in.dat(5);
d0 <= wb_in.dat(4);
lcd_dout(0) <= wb_in.dat(4);
doe1 <= wb_in.dat(3);
d1 <= wb_in.dat(2);
lcd_dout(1) <= wb_in.dat(2);
csoe <= wb_in.dat(1);
cs <= wb_in.dat(0);
end if;
else
-- c8050018, touchscreen status register
rdat := 4x"0" & xadc_busy & eoc_stat & eos_stat & tsctrl;
rd_data <= rdat & rdat & rdat & rdat;
if wb_in.we = '1' and wb_in.sel(0) = '1' then
-- for eoc_stat and eos_state, write 0 to clear
if wb_in.dat(2) = '0' then
eoc_stat <= '0';
end if;
if wb_in.dat(1) = '0' then
eos_stat <= '0';
end if;
end if;
end if;
else
-- c80501xx, access to the XADC DRP port
xadc_en <= '1';
xadc_we <= wb_in.we;
xadc_addr(6 downto 1) <= wb_in.adr(5 downto 0);
if wb_in.sel(1 downto 0) = "00" then
xadc_di <= wb_in.dat(31 downto 16);
xadc_addr(0) <= '1';
state <= drp_hi;
else
xadc_di <= wb_in.dat(15 downto 0);
xadc_addr(0) <= '0';
state <= drp_lo;
end if;
end if;
else
if tsctrl = '0' then
cs <= '1';
end if;
end if;
when prep1 =>
lcd_doe <= req_wr;
doe0 <= req_wr;
doe1 <= req_wr;
if req_wr = '1' then
if wr_sel(1 downto 0) /= "00" then
if wr_sel(1) = '1' then
lcd_dout <= wr_data(15 downto 8);
wr_sel(1) <= '0';
else
lcd_dout <= wr_data(7 downto 0);
wr_sel(0) <= '0';
end if;
else
if wr_sel(3) = '1' then
lcd_dout <= wr_data(31 downto 24);
wr_sel(3) <= '0';
else
lcd_dout <= wr_data(23 downto 16);
wr_sel(2) <= '0';
end if;
end if;
end if;
state <= prep2;
when prep2 =>
if req_wr = '1' then
lcd_wr <= '0'; -- active low
state <= writing;
delay <= to_unsigned(1, 6);
else
lcd_rd <= '0';
state <= reading;
delay <= to_unsigned(35, 6);
end if;
when writing =>
-- last cycle of writing state
lcd_wr <= '1';
if wr_sel = "0000" then
state <= idle;
idle1 <= '1';
else
state <= wr_pause;
end if;
when wr_pause =>
state <= prep1;
when reading =>
-- last cycle of reading state
lcd_rd <= '1';
rd_data <= lcd_din & lcd_din & lcd_din & lcd_din;
ack <= '1';
state <= rd_recovery;
delay <= to_unsigned(6, 6);
when rd_recovery =>
state <= idle;
when drp_lo =>
if xadc_rdy = '1' then
rd_data(15 downto 0) <= xadc_do;
if wr_sel(3 downto 2) = "00" then
ack <= '1';
state <= idle;
else
xadc_di <= wr_data(31 downto 16);
xadc_addr(0) <= '1';
state <= drp_hi;
end if;
end if;
when drp_hi =>
if xadc_rdy = '1' then
rd_data(31 downto 16) <= xadc_do;
ack <= '1';
state <= idle;
end if;
end case;
end if;
end if;
end process;
end architecture;