IOP16 PS/2 Keyboard

PS/2 Keyboard

• Wrapper for PS/2 keyboard interfaces
• PS/2 to ASCII conversion

Software Interface

Status register (Read only)

• Addr = 0
• Value = 0x00, No data present
• Value = 0x01, Data present

Data register (Read only)

• Addr = 1
• ASCII Data

Hook-up

• Add to Top Level VHDL code

Pins

• Add to top level entity pins list

  -- PS/2 
  ps2Clk  : inout std_logic;
  ps2Data : inout std_logic;

Signals

• Add signal into architecture section

-- Decodes/Strobes
...
 signal w_kbcs : std_logic;

-- Interfaces
...
  signal w_KbdData  :  std_logic_vector(7 downto 0);

VHDL Instance

-- PS/2 keyboard/mapper to ANSI
KEYBOARD : ENTITY  WORK.Wrap_Keyboard
port MAP (
  i_CLOCK_50 => i_clk,
  i_n_reset  => w_resetClean_n,
  i_kbCS     => w_kbcs,
  i_RegSel   => w_periphAdr(0),
  i_rd_Kbd   => w_kbcs,
  i_ps2_clk  => ps2Clk,
  i_ps2_data => ps2Data,
  o_kbdDat   => w_KbdData
);

Hook-up Strobes/Read Mux

• Add to strobes and read mux

-- Strobes/Selects
  ...
  w_kbcs <= '1' when (w_periphAdr(7 downto 1) = "0000110") and (w_periphRd = '1') else '0';

-- Peripheral bus read mux
  w_periphIn <= ...
    w_KbdData  when w_periphAdr(7 downto 1) = "0000110"	else
  ...

Resources

• Logic Cells: 708
• Registers: 95
• Memory Bits: 0
• M9Ks: 0