| Line 134... |
Line 134... |
-- Sanity Checks --------------------------------------------------------------------------
|
-- Sanity Checks --------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- max bus timeout latency lower than recommended --
|
-- max bus timeout latency lower than recommended --
|
assert not (bus_timeout_c <= 32) report "NEORV32 PROCESSOR CONFIG ERROR: Bus timeout (neorv32_package.vhd:bus_timeout_c) should be >32 when using external bus interface." severity error;
|
assert not (bus_timeout_c <= 32) report "NEORV32 PROCESSOR CONFIG ERROR: Bus timeout (neorv32_package.vhd:bus_timeout_c) should be >32 when using external bus interface." severity error;
|
-- external memory iterface protocol + max timeout latency notifier (warning) --
|
-- external memory iterface protocol + max timeout latency notifier (warning) --
|
assert not (wb_pipe_mode_c = false) report "NEORV32 PROCESSOR CONFIG NOTE: Implementing external memory interface using STANDARD Wishbone protocol with max latency = " & integer'image(bus_timeout_c) & " cycles." severity warning;
|
assert not (wb_pipe_mode_c = false) report "NEORV32 PROCESSOR CONFIG NOTE: Implementing external memory interface using STANDARD Wishbone protocol with max latency = " & integer'image(bus_timeout_c) & " cycles." severity note;
|
assert not (wb_pipe_mode_c = true) report "NEORV32 PROCESSOR CONFIG NOTE: Implementing external memory interface using PIEPLINED Wishbone protocol with max latency = " & integer'image(bus_timeout_c) & " cycles." severity warning;
|
assert not (wb_pipe_mode_c = true) report "NEORV32 PROCESSOR CONFIG WARNING! Implementing external memory interface using PIEPLINED Wishbone protocol with max latency = " & integer'image(bus_timeout_c) & " cycles." severity warning;
|
|
-- endianness --
|
|
assert not (xbus_big_endian_c = false) report "NEORV32 PROCESSOR CONFIG NOTE: Using LITTLE-ENDIAN byte order for external memory interface." severity note;
|
|
assert not (xbus_big_endian_c = true) report "NEORV32 PROCESSOR CONFIG NOTE: Using BIG-ENDIAN byte order for external memory interface." severity note;
|
|
|
|
|
-- Access Control -------------------------------------------------------------------------
|
-- Access Control -------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- access to processor-internal IMEM or DMEM? --
|
-- access to processor-internal IMEM or DMEM? --
|
| Line 184... |
Line 187... |
ctrl.rd_req <= '0';
|
ctrl.rd_req <= '0';
|
ctrl.wr_req <= '0';
|
ctrl.wr_req <= '0';
|
-- buffer all outgoing signals --
|
-- buffer all outgoing signals --
|
ctrl.we <= wren_i;
|
ctrl.we <= wren_i;
|
ctrl.adr <= addr_i;
|
ctrl.adr <= addr_i;
|
|
if (xbus_big_endian_c = true) then -- endianness conversion
|
ctrl.wdat <= data_i;
|
ctrl.wdat <= data_i;
|
ctrl.sel <= ben_i;
|
ctrl.sel <= ben_i;
|
|
else
|
|
ctrl.wdat <= bswap32_f(data_i);
|
|
ctrl.sel <= bit_rev_f(ben_i);
|
|
end if;
|
ctrl.src <= src_i;
|
ctrl.src <= src_i;
|
ctrl.lock <= lock_i;
|
ctrl.lock <= lock_i;
|
ctrl.priv <= priv_i;
|
ctrl.priv <= priv_i;
|
-- valid new or buffered read/write request --
|
-- valid new or buffered read/write request --
|
if ((xbus_access and (wren_i or ctrl.wr_req or rden_i or ctrl.rd_req)) = '1') then
|
if ((xbus_access and (wren_i or ctrl.wr_req or rden_i or ctrl.rd_req)) = '1') then
|
| Line 233... |
Line 241... |
end case;
|
end case;
|
end if;
|
end if;
|
end process bus_arbiter;
|
end process bus_arbiter;
|
|
|
-- host access --
|
-- host access --
|
data_o <= ctrl.rdat;
|
data_o <= ctrl.rdat when (xbus_big_endian_c = true) else bswap32_f(ctrl.rdat); -- endianness conversion
|
ack_o <= ctrl.ack;
|
ack_o <= ctrl.ack;
|
err_o <= ctrl.err;
|
err_o <= ctrl.err;
|
|
|
-- wishbone interface --
|
-- wishbone interface --
|
wb_tag_o(0) <= '1' when (ctrl.priv = priv_mode_m_c) else '0'; -- privileged access when in machine mode
|
wb_tag_o(0) <= '1' when (ctrl.priv = priv_mode_m_c) else '0'; -- privileged access when in machine mode
|
