vme-wb: allow switching between normal and direct-access modes

35f60fbe · Michael Reese · a77a693a · 35f60fbe
Commit 35f60fbe authored Aug 14, 2017 by Michael Reese
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Showing with 9 additions and 4 deletions

VME_Wb_master_eb.vhd hdl/VME_Wb_master_eb.vhd +9 -4

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--- a/hdl/VME_Wb_master_eb.vhd
+++ b/hdl/VME_Wb_master_eb.vhd
@@ -124,7 +124,8 @@ architecture Behavioral of VME_Wb_interface is
   signal s_bridge_state : bridge_state_t := state_normal;
   signal ee_backdoor_wb_rw    : std_logic;
   signal ee_backdoor_wb_addr  : std_logic_vector(31 downto 0);
-   signal wb_base_addr         : std_logic_vector(31 downto 0); -- configurable base addreess for WB-access
+   signal wb_base_addr         : std_logic_vector(31 downto 0) := x"ffffffff"; -- configurable base addreess for WB-access
+                                                                               -- 0xffffffff means "normal mode"

 --===========================================================================
 -- Architecture begin
@@ -243,6 +244,8 @@ begin
            case rel_locAddr_i(5 downto 2) is -- 24 bits access valid addres 0/8/16/24/32 ..
               when "0000" => -- ERROR 
                  s_data_ctrl <= s_error_ctrl;
+               when "0001" => -- READ BASE ADDR OF EE-BACKDOOR MODE
+                  s_data_ctrl <= wb_base_addr;
               when "0010" => -- SDWD
                  s_data_ctrl <= g_sdb_addr;
               when "0100" => -- CTRL
@@ -267,10 +270,12 @@ begin
            if RW_i = '0' and memReq_i = '1' and cardSel_i = '1' then
               case rel_locAddr_i(5 downto 2) is
                  when "0001" => -- SWITCH TO EE-BACKDOOR MODE
-                      s_bridge_state <= state_ee_backdoor_idle;
-                      wb_base_addr   <= locDataInSwap_i(31 downto 0);
-                  when "0011" => -- SWITCH TO NORMAL MODE
+                    wb_base_addr   <= locDataInSwap_i(31 downto 0);
+                    if locDataInSwap_i(31 downto 0) = x"ffffffff" then
                      s_bridge_state <= state_normal;
+                    else 
+                      s_bridge_state <= state_ee_backdoor_idle;
+                    end if;
                  when "0100" =>  -- CTRL
                         if locDataInSwap_i(30) = '1' then  -- write 
                            s_cyc_d  <= locDataInSwap_i(31);