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Diffstat (limited to 'basys3/basys3.srcs/ppu_pceg.vhd')
-rw-r--r--basys3/basys3.srcs/ppu_pceg.vhd30
1 files changed, 16 insertions, 14 deletions
diff --git a/basys3/basys3.srcs/ppu_pceg.vhd b/basys3/basys3.srcs/ppu_pceg.vhd
index 5d9f4d6..d53d86a 100644
--- a/basys3/basys3.srcs/ppu_pceg.vhd
+++ b/basys3/basys3.srcs/ppu_pceg.vhd
@@ -5,34 +5,36 @@ use work.ppu_consts.all;
entity ppu_pceg is port(
CLK : in std_logic; -- system clock
RESET : in std_logic; -- async reset
- SPRITE : out std_logic; -- sprite info fetch + sprite pixel fetch
+ SPRITE_BG : out std_logic; -- sprite info fetch + sprite pixel fetch
+ SPRITE_FG : out std_logic; -- sprite pixel fetch
DONE : out std_logic; -- last pipeline stage done
READY : out std_logic); -- rgb buffer propagation ready
end ppu_pceg;
architecture Behavioral of ppu_pceg is
- type states is (PL_SPRITE, PL_DONE, PL_READY);
- signal state : states := PL_SPRITE;
+ signal PL_SPRITE_BG, PL_SPRITE_FG, PL_DONE, PL_READY : boolean := false;
begin
-- output drivers
- SPRITE <= CLK when RESET = '0' and state = PL_SPRITE else '0';
- DONE <= CLK when RESET = '0' and state = PL_DONE else '0';
- READY <= '1' when RESET = '0' and state = PL_READY else '0';
+ SPRITE_BG <= CLK when RESET = '0' and PL_SPRITE_BG else '0';
+ SPRITE_FG <= CLK when RESET = '0' and PL_SPRITE_FG else '0';
+ DONE <= CLK when RESET = '0' and PL_DONE else '0';
+ READY <= '1' when RESET = '0' and PL_READY else '0';
process(CLK, RESET)
variable CLK_IDX : natural range 0 to PPU_PL_TOTAL_STAGES+1 := 0;
begin
if RESET = '1' then
- state <= PL_SPRITE;
+ CLK_IDX := 0;
+ PL_SPRITE_BG <= false;
+ PL_SPRITE_FG <= false;
+ PL_DONE <= false;
+ PL_READY <= false;
elsif rising_edge(CLK) then
-- clock counter ranges
- if CLK_IDX < 4 then
- state <= PL_SPRITE;
- elsif CLK_IDX < 5 then
- state <= PL_DONE;
- else
- state <= PL_READY;
- end if;
+ PL_SPRITE_BG <= true when CLK_IDX >= 0 and CLK_IDX <= 3 else false;
+ PL_SPRITE_FG <= true when CLK_IDX >= 1 and CLK_IDX <= 2 else false;
+ PL_DONE <= true when CLK_IDX = 4 else false;
+ PL_READY <= true when CLK_IDX >= 5 else false;
-- increment clock counter
CLK_IDX := CLK_IDX + 1;