1 files changed, 0 insertions, 110 deletions
diff --git a/PIC/dpram.vhd b/PIC/dpram.vhd
deleted file mode 100644
index 44d7adf..0000000
--- a/PIC/dpram.vhd
+++ /dev/null
@@ -1,110 +0,0 @@
-library ieee;
-use ieee.std_logic_1164.all;
-use ieee.numeric_std.all;
-
--- Data memory with UART memory-mapped registers.
--- Addresses 0x70-0x72 are used (unimplemented in real PIC16F84A, no header conflict):
---   0x70  UART_TX     write: send byte (held until tx_done)
---   0x71  UART_RX     read:  current FIFO head (FWFT), pulses rd_en to pop
---   0x72  UART_STATUS read:  "00000" & rx_full & rx_empty & tx_busy
-
-entity dpram is
-  generic (DEPTH : positive := 128);
-  port (
-    clk      : in  std_logic;
-    we       : in  std_logic;
-    re       : in  std_logic;
-    d        : in  std_logic_vector(7 downto 0);
-    d_status : in  std_logic_vector(7 downto 0);
-    addr     : in  std_logic_vector(6 downto 0);
-    q        : out std_logic_vector(7 downto 0);
-    q_status : out std_logic_vector(2 downto 0);
-
-    port_a    : out std_logic_vector(7 downto 0);
-    port_b    : out std_logic_vector(7 downto 0);
-    we_status : in  std_logic;
-
-    -- UART interface
-    uart_tx_byte  : out std_logic_vector(7 downto 0) := (others => '0');
-    uart_tx_send  : out std_logic                    := '0';
-    uart_tx_done  : in  std_logic;
-    uart_rx_byte  : in  std_logic_vector(7 downto 0);
-    uart_rx_rd_en : out std_logic                    := '0';
-    uart_rx_empty : in  std_logic;
-    uart_rx_full  : in  std_logic
-  );
-end entity dpram;
-
-architecture rtl of dpram is
-  type mem_t is
-    array (0 to DEPTH - 1)
-    of std_logic_vector(7 downto 0);
-
-  signal mem             : mem_t     := (others => (others => '0'));
-  signal uart_tx_pending : std_logic := '0';
-
-begin
-  -- STATUS output is combinatorial
-  q_status <= mem(16#03#)(2 downto 0);
-
-  port_a <= mem(16#05#);
-  port_b <= mem(16#06#);
-
-  -- tx_send is high while a transmission is in progress
-  uart_tx_send <= uart_tx_pending;
-
-  -- SR: set when CPU writes to 0x08, clear when UART asserts tx_done
-  tx_ctrl : process(clk)
-  begin
-    if rising_edge(clk) then
-      if we = '1' and addr = "1110000" then   -- 0x70 UART_TX
-        uart_tx_byte    <= d;
-        uart_tx_pending <= '1';
-      elsif uart_tx_done = '1' then
-        uart_tx_pending <= '0';
-      end if;
-    end if;
-  end process tx_ctrl;
-
-  read : process(clk)
-  begin
-    if rising_edge(clk) then
-      uart_rx_rd_en <= '0';   -- default: no pop
-      if re = '1' then
-        if addr = "1110001" then              -- 0x71 UART_RX
-          q <= uart_rx_byte;                  -- FWFT head, valid combinatorially
-          if uart_rx_empty = '0' then
-            uart_rx_rd_en <= '1';             -- advance FIFO pointer
-          end if;
-        elsif addr = "1110010" then           -- 0x72 UART_STATUS
-          q <= "00000" & uart_rx_full & uart_rx_empty & uart_tx_pending;
-        else
-          q <= mem(to_integer(unsigned(addr)));
-        end if;
-      end if;
-    end if;
-  end process read;
-
-  write : process(clk)
-  begin
-    if rising_edge(clk) then
-      if we_status = '1' then
-        mem(16#03#) <= d_status;
-      end if;
-      if we = '1' then
-        if addr = "0000011" then              -- 0x03 STATUS: direct write
-          mem(16#03#) <= d;
-        elsif addr = "1110000" or            -- 0x70 UART_TX
-              addr = "1110001" or            -- 0x71 UART_RX (read-only but handled gracefully)
-              addr = "1110010" then          -- 0x72 UART_STATUS (read-only)
-          -- UART-mapped addresses: don't write to RAM; still update STATUS
-          mem(16#03#) <= d_status;
-        else
-          mem(16#03#) <= d_status;
-          mem(to_integer(unsigned(addr))) <= d;
-        end if;
-      end if;
-    end if;
-  end process write;
-
-end architecture rtl;