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- Added Bus timeout detection

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- STB_O, ADDR_O registered to output when SRDY


git-svn-id: http://moon:8086/svn/vhdl/trunk@31 cc03376c-175c-47c8-b038-4cd826a8556b
This commit is contained in:
jens
2008-10-09 11:50:07 +00:00
parent b117df0bc9
commit 2a0d20f4b2
1 changed files with 58 additions and 8 deletions
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lib/CPUs/MIPS/src/core/mips_bui.vhd
+58 -8
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@@ -43,10 +43,12 @@ entity bui is
CYC_O : out STD_LOGIC;
STB_O : out STD_LOGIC;
MRDY_O : out STD_LOGIC;
cpu_imem_err : out STD_LOGIC;
cpu_imem_rdy : out STD_LOGIC;
cpu_imem_en : in STD_LOGIC;
cpu_imem_addr : in word_t;
cpu_imem_din : out word_t;
cpu_dmem_err : out STD_LOGIC;
cpu_dmem_rdy : out STD_LOGIC;
cpu_dmem_en : in STD_LOGIC;
cpu_dmem_re : in STD_LOGIC;
@@ -139,6 +141,10 @@ architecture behavior of bui is
signal dcache_en : std_logic;
signal uncached_access : std_logic;
type timeout_cnt_t is range 0 to 1E5-1;
signal bus_timeout_cnt : timeout_cnt_t;
signal bus_timeout : std_logic;
begin
bus_strobe:
@@ -149,9 +155,9 @@ bus_strobe:
STB_O <= '0';
elsif dmem_mem_gnt = '1' then
STB_O <= STB_O_dmem;
elsif dcache_mem_gnt = '1' then
elsif SRDY_I_dcache = '1' then
STB_O <= STB_O_dcache;
elsif icache_mem_gnt = '1' then
elsif SRDY_I_icache = '1' then
STB_O <= STB_O_icache;
elsif SRDY_I = '1' then
STB_O <= '0';
@@ -159,27 +165,40 @@ bus_strobe:
end if;
end process;
bus_cycle:
process(CLK_I)
begin
if rising_edge(CLK_I) then
CYC_O <= '0';
if dmem_mem_gnt = '1' then
CYC_O <= CYC_O_dmem;
elsif dcache_mem_gnt = '1' then
CYC_O <= CYC_O_dcache;
elsif icache_mem_gnt = '1' then
CYC_O <= CYC_O_icache;
end if;
end if;
end process;
bus_out:
process(CLK_I)
begin
if rising_edge(CLK_I) then
CYC_O <= '0';
if RST_I = '1' then
ADDR_O <= (others => '0');
DAT_O <= (others => '0');
WE_O <= '0';
SEL_O <= (others => '0');
elsif dmem_mem_gnt = '1' then
CYC_O <= CYC_O_dmem;
ADDR_O <= ADDR_O_dmem;
DAT_O <= DAT_O_dmem;
WE_O <= WE_O_dmem;
SEL_O <= SEL_O_dmem;
elsif dcache_mem_gnt = '1' then
CYC_O <= CYC_O_dcache;
elsif SRDY_I_dcache = '1' then
ADDR_O <= ADDR_O_dcache;
WE_O <= '0';
SEL_O <= (others => '0');
elsif icache_mem_gnt = '1' then
CYC_O <= CYC_O_icache;
elsif SRDY_I_icache = '1' then
ADDR_O <= ADDR_O_icache;
WE_O <= '0';
SEL_O <= (others => '0');
@@ -361,6 +380,37 @@ bus_state:
end process;
bus_timeout_counter:
process(CLK_I)
begin
if rising_edge(CLK_I) then
if (icache_mem_gnt or dcache_mem_gnt or dmem_mem_gnt) = '1' then
if bus_timeout_cnt /= 0 then
bus_timeout_cnt <= bus_timeout_cnt - 1;
else
bus_timeout <= '1';
end if;
else
bus_timeout_cnt <= timeout_cnt_t'high;
bus_timeout <= '0';
end if;
end if;
end process;
bus_err:
process(CLK_I)
begin
if rising_edge(CLK_I) then
if RST_I = '1' then
cpu_imem_err <= '0';
cpu_dmem_err <= '0';
elsif bus_timeout = '1' then
cpu_imem_err <= icache_mem_gnt;
cpu_dmem_err <= dcache_mem_gnt or dmem_mem_gnt;
end if;
end if;
end process;
-------------------------------------------------------------------
end behavior;