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-- DISCLAIMED. IN NO EVENT SHALL JEREMY SETH HENRY BE LIABLE FOR ANY
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-- DISCLAIMED. IN NO EVENT SHALL JEREMY SETH HENRY BE LIABLE FOR ANY
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-- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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-- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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-- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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-- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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-- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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-- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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-- ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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-- ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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-- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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-- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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-- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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-- THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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--
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--
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-- VHDL Entity: o8_hd44780_8b
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-- VHDL Entity: o8_hd44780_8b
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-- Description: Provides low-level access to a "standard" character LCD using
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-- Description: Provides low-level access to a "standard" character LCD using
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-- the ST/HD44780(U) control ASIC wired in full (8-bit) mode.
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-- the ST/HD44780(U) control ASIC wired in full (8-bit) mode.
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-- All low-level timing of the control signals are handled by this
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-- All low-level timing of the control signals are handled by
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-- module, allowing client firmware to use a simple register
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-- this module, allowing client firmware to use a simple
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-- interface to program the LCD panel.
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-- register interface to program the LCD panel.
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-- Init routine initializes the display and displays a single
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-- Init routine initializes the display and displays a single
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-- character to demonstrate correct function, then listens for
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-- character to demonstrate correct function, then listens for
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-- user data on its external interface.
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-- user data on its external interface.
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--
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-- Register Map
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-- Address Function
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-- Offset Bitfield Description Read/Write
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-- 0x0 AAAAAAAA LCD Register Write (Write-only)
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-- 0x1 AAAAAAAA LCD Data Write (Write-only)
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-- 0x2 AAAAAAAA LCD Contrast (Read-Write)
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-- 0x3 AAAAAAAA LCD Backlight (Read-Write)
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--
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--------------------------------------------------------------------------------
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-- LCD Controller
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--------------------------------------------------------------------------------
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--
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-- LCD Instruction Set
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-- Instruction RS RW D7 D6 D5 D4 D3 D2 D1 D0 Time
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------------------------------------------------------------------------
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-- Clear Display | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1.52mS
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-- Return Home | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | x | 1.52mS
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-- Entry Mode | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | ID| S | 37uS
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-- Display Pwr | 0 | 0 | 0 | 0 | 0 | 0 | 1 | D | C | B | 37uS
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-- Cursor/Display Shift | 0 | 0 | 0 | 0 | 0 | 1 | SC| RL| x | x | 37uS
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-- Function Set | 0 | 0 | 0 | 0 | 1 | DL| N | F | x | x | 37uS
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-- Set CGRAM Address | 0 | 0 | 0 | 1 | A | A | A | A | A | A | 37uS
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-- Set DDRAM Address | 0 | 0 | 1 | A | A | A | A | A | A | A | 37uS
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-- Notes:
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-- ID = Increment/Decrement DDRAM Address (1 = increment, 0 = decrement)
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-- S = Shift Enable (1 = Shift display according to ID, 0 = Don't shift)
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-- D = Display On/Off (1 = on, 0 = off)
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-- C = Cursor On/Off (1 = on, 0 = off)
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-- B = Cursor Blink (1 = block cursor, 0 = underline cursor)
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-- SC / RL = Shift Cursor/Display Right/Left (see data sheet - not needed for init)
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-- F = Font (0 = 5x8, 1 = 5x11) Ignored on 2-line displays (N = 1)
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-- N = Number of Lines (0 = 1 lines, 1 = 2 lines)
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-- DL = Data Length (0 = 4-bit bus, 1 = 8-bit bus) This is fixed at 1 in this module
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-- A = Address (see data sheet for usage)
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--
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-- Revision History
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-- Author Date Change
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------------------ -------- ---------------------------------------------------
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-- Seth Henry 01/22/13 Design Start
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-- Seth Henry 04/10/20 Code & comment cleanup
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library ieee;
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_unsigned.all;
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use ieee.std_logic_unsigned.all;
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use ieee.std_logic_arith.all;
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use ieee.std_logic_arith.all;
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Line 128... |
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signal Reg_Valid : std_logic := '0';
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signal Reg_Valid : std_logic := '0';
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signal Reg_Sel : std_logic := '0';
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signal Reg_Sel : std_logic := '0';
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signal Reg_Data : DATA_TYPE := x"00";
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signal Reg_Data : DATA_TYPE := x"00";
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signal Tx_Ready : std_logic;
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signal Tx_Ready : std_logic := '0';
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--------------------------------------------------------------------------------
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-- LCD Controller
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--------------------------------------------------------------------------------
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-- Register Map
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-- Address Function
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-- Offset Bitfield Description Read/Write
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-- 0x0 AAAAAAAA LCD Register Write (Write-only)
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-- 0x1 AAAAAAAA LCD Data Write (Write-only)
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-- 0x2 AAAAAAAA LCD Contrast (Read-Write)
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-- 0x3 AAAAAAAA LCD Backlight (Read-Write)
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-- LCD Instruction Set
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-- Instruction RS RW D7 D6 D5 D4 D3 D2 D1 D0 Time
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------------------------------------------------------------------------
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-- Clear Display | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1.52mS
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-- Return Home | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | x | 1.52mS
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-- Entry Mode | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | ID| S | 37uS
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-- Display Pwr | 0 | 0 | 0 | 0 | 0 | 0 | 1 | D | C | B | 37uS
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-- Cursor/Display Shift | 0 | 0 | 0 | 0 | 0 | 1 | SC| RL| x | x | 37uS
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-- Function Set | 0 | 0 | 0 | 0 | 1 | DL| N | F | x | x | 37uS
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-- Set CGRAM Address | 0 | 0 | 0 | 1 | A | A | A | A | A | A | 37uS
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-- Set DDRAM Address | 0 | 0 | 1 | A | A | A | A | A | A | A | 37uS
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-- Notes:
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-- ID = Increment/Decrement DDRAM Address (1 = increment, 0 = decrement)
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-- S = Shift Enable (1 = Shift display according to ID, 0 = Don't shift)
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-- D = Display On/Off (1 = on, 0 = off)
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-- C = Cursor On/Off (1 = on, 0 = off)
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-- B = Cursor Blink (1 = block cursor, 0 = underline cursor)
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-- SC / RL = Shift Cursor/Display Right/Left (see data sheet - not needed for init)
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-- F = Font (0 = 5x8, 1 = 5x11) Ignored on 2-line displays (N = 1)
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-- N = Number of Lines (0 = 1 lines, 1 = 2 lines)
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-- DL = Data Length (0 = 4-bit bus, 1 = 8-bit bus) This is fixed at 1 in this module
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-- A = Address (see data sheet for usage)
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constant LCD_CONFIG1 : std_logic_vector(7 downto 0) := x"38"; -- Set 4-bit, 2-line mode
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constant LCD_CONFIG1 : std_logic_vector(7 downto 0) := x"38"; -- Set 4-bit, 2-line mode
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constant LCD_CONFIG2 : std_logic_vector(7 downto 0) := x"0C"; -- Turn display on, no cursor
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constant LCD_CONFIG2 : std_logic_vector(7 downto 0) := x"0C"; -- Turn display on, no cursor
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constant LCD_CONFIG3 : std_logic_vector(7 downto 0) := x"01"; -- Clear display
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constant LCD_CONFIG3 : std_logic_vector(7 downto 0) := x"01"; -- Clear display
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constant LCD_CONFIG4 : std_logic_vector(7 downto 0) := x"06"; -- Positive increment, no shift
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constant LCD_CONFIG4 : std_logic_vector(7 downto 0) := x"06"; -- Positive increment, no shift
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