--apu register access process
reg_set_p : process (rst_n, ce_n, r_nw, cpu_addr, cpu_d)
begin
- if (rst_n = '1' and ce_n = '0') then
- if (r_nw = '0') then
- --apu write
- cpu_d <= (others => 'Z');
- if (cpu_addr(4 downto 0) = OAM_DMA) then
- dma_start_n <= '0';
- else
- dma_start_n <= '1';
- end if;
- elsif (r_nw = '1') then
- --apu read
- if (cpu_addr(4 downto 0) = OAM_JP1) then
- cpu_d <= (others => '0');
- elsif (cpu_addr(4 downto 0) = OAM_JP2) then
- cpu_d <= (others => '0');
- else
- --return dummy zero vale.
- cpu_d <= (others => '0');
- end if;
- end if;
- else
- cpu_d <= (others => 'Z');
+ if (rst_n = '0') then
+-- cpu_d <= (others => 'Z');
dma_start_n <= '1';
- end if; --if (rst_n = '1' and ce_n = '0')
+ elsif (rising_edge(clk)) then
+-- if (ce_n = '0') then
+-- if (r_nw = '0') then
+-- --apu write
+-- cpu_d <= (others => 'Z');
+-- if (cpu_addr(4 downto 0) = OAM_DMA) then
+-- dma_start_n <= '0';
+-- else
+-- dma_start_n <= '1';
+-- end if;
+-- elsif (r_nw = '1') then
+-- dma_start_n <= '1';
+--
+-- --joy pad read
+-- if (cpu_addr(4 downto 0) = OAM_JP1) then
+-- cpu_d <= (others => '0');
+-- elsif (cpu_addr(4 downto 0) = OAM_JP2) then
+-- cpu_d <= (others => '0');
+-- else
+-- --return dummy zero vale.
+-- cpu_d <= (others => '0');
+-- end if;
+-- end if;
+-- else
+-- cpu_d <= (others => 'Z');
+-- dma_start_n <= '1';
+-- end if; --if (ce_n = '0')
+ end if; --if (rst_n = '0') then
end process;
--dma operation process
begin
if (rst_n = '0') then
dma_next_status <= DMA_ST_IDLE;
+ dma_status_we_n <= '1';
dma_end_n <= '1';
- rdy <= '1';
dma_process_n <= '1';
cpu_addr <= (others => 'Z');
cpu_d <= (others => 'Z');
r_nw <= 'Z';
- else
- if (clk'event and clk = '0') then
- if (dma_start_n = '0') then
- --pull rdy pin down to stop cpu bus accessing.
- rdy <= '0';
- end if;
- if (dma_end_n = '0') then
- --pull rdy pin up to re-enable cpu bus accessing.
- rdy <= '1';
- end if;
- end if;
-
- if (clk'event and clk = '1') then
- if (dma_status = DMA_ST_IDLE) then
- if (dma_start_n = '0') then
- dma_status_we_n <= '0';
- dma_next_status <= DMA_ST_SETUP;
- end if;
- dma_process_n <= '1';
- dma_end_n <= '1';
- cpu_addr <= (others => 'Z');
- cpu_d <= (others => 'Z');
- r_nw <= 'Z';
- elsif (dma_status = DMA_ST_SETUP) then
- cpu_addr <= OAMADDR;
- cpu_d <= (others => '0');
- r_nw <= '0';
- dma_next_status <= DMA_ST_PROCESS;
- elsif (dma_status = DMA_ST_PROCESS) then
- if (dma_addr(dsize - 1 downto 0) = "11111111" and dma_cnt_ce_n(0) = '1') then
- dma_status_we_n <= '0';
- dma_next_status <= DMA_ST_IDLE;
- dma_end_n <= '0';
- else
- dma_status_we_n <= '1';
- dma_process_n <= '0';
- dma_end_n <= '1';
- end if;
-
- if (dma_cnt_ce_n(0) = '0') then
- r_nw <= '1';
- cpu_addr <= dma_addr;
- cpu_d <= (others => 'Z');
- elsif (dma_cnt_ce_n(0) = '1') then
- r_nw <= '0';
- cpu_addr <= OAMDATA;
- cpu_d <= oam_data;
- end if;
- end if;--if (dma_status = DMA_ST_IDLE) then
- end if;--if (clk'event and clk = '1') then
+ elsif (rising_edge(clk)) then
+-- if (dma_status = DMA_ST_IDLE) then
+-- if (dma_start_n = '0') then
+-- dma_status_we_n <= '0';
+-- dma_next_status <= DMA_ST_SETUP;
+-- end if;
+-- dma_process_n <= '1';
+-- dma_end_n <= '1';
+-- cpu_addr <= (others => 'Z');
+-- cpu_d <= (others => 'Z');
+-- r_nw <= 'Z';
+-- elsif (dma_status = DMA_ST_SETUP) then
+-- cpu_addr <= OAMADDR;
+-- cpu_d <= (others => '0');
+-- r_nw <= '0';
+-- dma_next_status <= DMA_ST_PROCESS;
+-- elsif (dma_status = DMA_ST_PROCESS) then
+-- if (dma_addr(dsize - 1 downto 0) = "11111111" and dma_cnt_ce_n(0) = '1') then
+-- dma_status_we_n <= '0';
+-- dma_next_status <= DMA_ST_IDLE;
+-- dma_end_n <= '0';
+-- else
+-- dma_status_we_n <= '1';
+-- dma_process_n <= '0';
+-- dma_end_n <= '1';
+-- end if;
+--
+-- if (dma_cnt_ce_n(0) = '0') then
+-- r_nw <= '1';
+-- cpu_addr <= dma_addr;
+-- cpu_d <= (others => 'Z');
+-- elsif (dma_cnt_ce_n(0) = '1') then
+-- r_nw <= '0';
+-- cpu_addr <= OAMDATA;
+-- cpu_d <= oam_data;
+-- end if;
+-- end if;--if (dma_status = DMA_ST_IDLE) then
+ end if;--if (rst_n = '0') then
+ end process;
+
+ rdy_p : process (rst_n, clk_n)
+ begin
+ if (rst_n = '0') then
+ rdy <= '1';
+ elsif (rising_edge(clk_n)) then
+-- if (dma_start_n = '0') then
+-- --pull rdy pin down to stop cpu bus accessing.
+-- rdy <= '0';
+-- elsif (dma_end_n = '0') then
+-- --pull rdy pin up to re-enable cpu bus accessing.
+-- rdy <= '1';
+-- else
+-- rdy <= '1';
+-- end if;
end if;
end process;
OSDN Git Service
