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Index: atari800core_mcc.vhd
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===================================================================
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--- atari800core_mcc.vhd (revision 270)
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+++ atari800core_mcc.vhd (working copy)
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@@ -245,8 +223,15 @@
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signal CLK_SDRAM : std_logic;
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-- SDRAM
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+ signal PREREG_SDRAM_REQUEST : std_logic;
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+ signal PREREG_SDRAM_READ_ENABLE : STD_LOGIC;
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+ signal PREREG_SDRAM_WRITE_ENABLE : std_logic;
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+ signal PREREG_SDRAM_ADDR : STD_LOGIC_VECTOR(22 DOWNTO 0);
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+ SIGNAL PREREG_SDRAM_DI : std_logic_vector(31 downto 0);
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+ SIGNAL PREREG_SDRAM_WIDTH_32BIT_ACCESS : std_logic;
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+ SIGNAL PREREG_SDRAM_WIDTH_16BIT_ACCESS : std_logic;
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+ SIGNAL PREREG_SDRAM_WIDTH_8BIT_ACCESS : std_logic;
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signal SDRAM_REQUEST : std_logic;
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- signal SDRAM_REQUEST_COMPLETE : std_logic;
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signal SDRAM_READ_ENABLE : STD_LOGIC;
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signal SDRAM_WRITE_ENABLE : std_logic;
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signal SDRAM_ADDR : STD_LOGIC_VECTOR(22 DOWNTO 0);
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@@ -254,6 +239,8 @@
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SIGNAL SDRAM_WIDTH_32BIT_ACCESS : std_logic;
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SIGNAL SDRAM_WIDTH_16BIT_ACCESS : std_logic;
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SIGNAL SDRAM_WIDTH_8BIT_ACCESS : std_logic;
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+
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+ signal SDRAM_REQUEST_COMPLETE : std_logic;
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signal SDRAM_REFRESH : std_logic;
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@@ -570,16 +535,16 @@
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CONSOL_SELECT => CONSOL_SELECT,
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CONSOL_START => CONSOL_START,
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- SDRAM_REQUEST => SDRAM_REQUEST,
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+ SDRAM_REQUEST => PREREG_SDRAM_REQUEST,
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SDRAM_REQUEST_COMPLETE => SDRAM_REQUEST_COMPLETE,
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- SDRAM_READ_ENABLE => SDRAM_READ_ENABLE,
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- SDRAM_WRITE_ENABLE => SDRAM_WRITE_ENABLE,
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- SDRAM_ADDR => SDRAM_ADDR,
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+ SDRAM_READ_ENABLE => PREREG_SDRAM_READ_ENABLE,
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+ SDRAM_WRITE_ENABLE => PREREG_SDRAM_WRITE_ENABLE,
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+ SDRAM_ADDR => PREREG_SDRAM_ADDR,
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SDRAM_DO => ram_do_reg,
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- SDRAM_DI => SDRAM_DI,
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- SDRAM_32BIT_WRITE_ENABLE => SDRAM_WIDTH_32bit_ACCESS,
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- SDRAM_16BIT_WRITE_ENABLE => SDRAM_WIDTH_16bit_ACCESS,
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- SDRAM_8BIT_WRITE_ENABLE => SDRAM_WIDTH_8bit_ACCESS,
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+ SDRAM_DI => PREREG_SDRAM_DI,
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+ SDRAM_32BIT_WRITE_ENABLE => PREREG_SDRAM_WIDTH_32bit_ACCESS,
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+ SDRAM_16BIT_WRITE_ENABLE => PREREG_SDRAM_WIDTH_16bit_ACCESS,
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+ SDRAM_8BIT_WRITE_ENABLE => PREREG_SDRAM_WIDTH_8bit_ACCESS,
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SDRAM_REFRESH => SDRAM_REFRESH,
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DMA_FETCH => dma_fetch,
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@@ -605,7 +570,7 @@
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process(clk_sdram,sdram_reset_ctrl_n_reg)
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begin
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if (sdram_reset_ctrl_n_reg='0') then
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- seq_reg <= "100000000000";
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+ seq_reg <= "010000000000";
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seq_ph_reg <= '1';
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ref_reg <= '0';
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@@ -653,7 +618,7 @@
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process(seq_reg, seq_next, sdram_rdy, sdram_reset_n_reg, reset_atari)
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begin
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sdram_reset_n_next <= sdram_reset_n_reg;
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- if (sdram_rdy = '1' and seq_next(8)='1' and seq_reg(8)='0') then
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+ if (sdram_rdy = '1' and seq_next(7)='1' and seq_reg(7)='0') then
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sdram_reset_n_next <= '1';
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end if;
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if (reset_atari = '1') then
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@@ -661,10 +626,34 @@
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end if;
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end process;
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+ -- register sdram request on the falling edge, 1/3 timing not enough, but 1/2 timing should be... This pushes back request 1 clock cycle. Result can also be clocking on the falling edge!
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+ process(clk,reset_n)
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+ begin
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+ if (reset_n='0') then
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+ SDRAM_REQUEST <= '0';
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+ SDRAM_READ_ENABLE <= '0';
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+ SDRAM_WRITE_ENABLE <= '0';
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+ SDRAM_ADDR <= (others=>'0');
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+ SDRAM_DI <= (others=>'0');
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+ SDRAM_WIDTH_32BIT_ACCESS <= '0';
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+ SDRAM_WIDTH_16BIT_ACCESS <= '0';
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+ SDRAM_WIDTH_8BIT_ACCESS <= '0';
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+ elsif(clk'event and clk='0') then -- FALLING EDGE
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+ SDRAM_REQUEST <= PREREG_SDRAM_REQUEST;
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+ SDRAM_READ_ENABLE <= PREREG_SDRAM_READ_ENABLE;
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+ SDRAM_WRITE_ENABLE <= PREREG_SDRAM_WRITE_ENABLE;
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+ SDRAM_ADDR <= PREREG_SDRAM_ADDR;
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+ SDRAM_DI <= PREREG_SDRAM_DI;
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+ SDRAM_WIDTH_32BIT_ACCESS <= PREREG_SDRAM_WIDTH_32BIT_ACCESS;
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+ SDRAM_WIDTH_16BIT_ACCESS <= PREREG_SDRAM_WIDTH_16BIT_ACCESS;
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+ SDRAM_WIDTH_8BIT_ACCESS <= PREREG_SDRAM_WIDTH_8BIT_ACCESS;
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+ end if;
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+ end process;
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+
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-- Adapt SDRAM
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process(sdram_request_reg, sdram_request, sdram_request_complete_reg, ram_do_reg, seq_reg, ram_do, ram_rd_active, ram_wr_active, SDRAM_WIDTH_8BIT_ACCESS, SDRAM_WRITE_ENABLE, SDRAM_READ_ENABLE, SDRAM_DI, SDRAM_ADDR)
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begin
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- sdram_request_next <= sdram_request_reg or sdram_request;
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+ sdram_request_next <= (sdram_request_reg or sdram_request) and not(sdram_request_complete_reg);
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sdram_request_complete_next <= sdram_request_complete_reg;
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ram_bena_next <= "00";
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ram_di_next <= (others=>'0');
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@@ -699,9 +688,9 @@
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when "000000001000" =>
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-- nop
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when "000000010000" =>
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- sdram_request_complete_next <= '0';
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-- nop
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when "000000100000" =>
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+ sdram_request_complete_next <= '0';
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-- nop
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when "000001000000" =>
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if (SDRAM_READ_ENABLE = '1') then
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@@ -732,9 +721,9 @@
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when "001000000000" =>
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-- nop
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when "010000000000" =>
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- sdram_request_complete_next <= '0';
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-- nop
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when "100000000000" =>
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+ sdram_request_complete_next <= '0';
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-- nop
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when others =>
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-- never
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