em_sdram.pm

SDRAM Controller For Altera SOPC Builder and NIOS on DE2 kit board

    if ($cas_pad == 1)
    {
      $cas_pad_expression = "1'b0,";
    }
    elsif ($cas_pad > 0)
    {
      $cas_pad_expression = "{$cas_pad\{1'b0}},";
    }
    else
    {
      $cas_pad_expression = "";
    }
    
    if ($WSA->{sdram_col_width} > 11)
    {
        $module->add_contents
            (

             e_signal->new({name => "cas_addr",
                            width => $WSA->{sdram_col_width} + 1}),
             e_assign->new
             (
              {
                  lhs => "cas_addr",
                  rhs => "f_select ? {$cas_pad_expression f_addr[$top_col_addr:10],1'b0,f_addr[9:$bottom_col_addr] } : ".
                                 "{$cas_pad_expression active_addr[$top_col_addr:10],1'b0,active_addr[9:$bottom_col_addr] }"
              }
              )
             );
    }
    elsif ($WSA->{sdram_col_width} == 11)
    {
        $module->add_contents
            (

             e_signal->new({name => "cas_addr",
                            width => $WSA->{sdram_col_width} + 1}),
             e_assign->new
             (
              {
                  lhs => "cas_addr",
                  rhs => "f_select ? {$cas_pad_expression f_addr[$top_col_addr],1'b0,f_addr[9:$bottom_col_addr] } : ".
                                 "{$cas_pad_expression active_addr[$top_col_addr],1'b0,active_addr[9:$bottom_col_addr] }"
              }
              )
             );
    }
    else
    {


        $cas_pad = $WSA->{sdram_addr_width} - $WSA->{sdram_col_width};
        $module->add_contents
            (
             e_signal->new({name => "cas_addr",
                            width => $WSA->{sdram_col_width} }),
             e_assign->new
             (
              {
                  lhs => "cas_addr",
                  rhs => "f_select ? { {".($cas_pad)."{1'b0}},f_addr[$top_col_addr:$bottom_col_addr] } : ".
                                 "{ {".($cas_pad)."{1'b0}},active_addr[$top_col_addr:$bottom_col_addr] }" }
              )
             );
    }







    my %m_contents_hash = 
        (
         $M_IDLE      =>
         [ # Note that the default IDLE cmd is INHIBIT (cs_ not asserted)
           e_if->new
           ({
               comment => "Wait for init-fsm to be done...",
               condition => "init_done",
               then => [
                        e_if->new
                        ({
                            comment=>"Hold bus if another cycle ended to arf.",
                            condition => "refresh_request",
                            then =>
                                [
                                 e_assign->new
                                 (["m_cmd" => "{".$ALL.",".$NOP."}"]),
                                 ],
                            else =>
                                [
                                 e_assign->new
                                 (["m_cmd" => $none_and_inhibit]),
                                 ],
                            }),
                        e_assign->new(["ack_refresh_request" => "1'b0"]),
                        e_if->new
                        ({
                            comment => "Wait for a read/write request.",
                            condition => "refresh_request",

                            then => 
                                [ 
                                  e_assign->news
                                  (
                                   ["m_state" => $M_PRE],
                                   ["m_next"  => $M_REF],
                                   ["m_count" => $trp],
                                   ["active_cs_n" => $csn_for_refresh], # for tristate...
                                   ),
                                  ], # end then
                            elsif => {
                                condition => "!f_empty",
                                then =>
                                    [
                                     e_assign->news
                                     (
                                      ["f_pop"  => "1'b1"],
                                      ["active_cs_n"    => "f_cs_n"],
                                      ["active_rnw"     => "f_rnw"],
                                      ["active_addr"    => "f_addr"],
                                      ["active_data"    => "f_data"],
                                      ["active_dqm"     => "f_dqm"],
                                      ["m_state"        => $M_RAS]
                                      ),
                                     ], # end then
                            }, # end elsif
                        }),   # end if
                        ],    # end init_done
               else => # !init_done
                   [
                    e_assign->new(["m_addr"     => "i_addr"]),
                    e_assign->new(["m_state"    => $M_IDLE]),
                    e_assign->new(["m_next"     => $M_IDLE]),
                    e_assign->new(["m_cmd"      => "i_cmd"]),
                    ], # end !init_done
               }),
           ], # end IDLE
         $M_RAS       =>  # Activate a row
         [
          e_assign->news
          (
           ["m_state"   => $M_WAIT],
           ["m_cmd"     => "{csn_decode,".$ACTIVE."}"],
           ["m_bank"    => "active_bank"],
           ["m_addr"    => "active_addr[$top_row_addr:$bottom_row_addr]"],
           ["m_data"    => "active_data"],
           ["m_dqm"     => "active_dqm"],
           ["m_count"   => $trcd],
           ["m_next"    => "active_rnw ? ".$M_RD." : ".$M_WR],
           ),
          ], # end RAS
         $M_REC       => # Recover from RD or WR before going to PRECHARGE.
         [       # In essence, a special type of M_WAIT state


                 e_assign->new(["m_cmd" => "{csn_decode,".$NOP."}"]),
                 e_if->new
                 ({
                     comment   => "Count down til safe to Proceed...",
                     condition => "m_count > 1",
                     then       => ["m_count" => "m_count - 1'b1"],
                     else      =>
                         [
                          e_assign->new(["m_state"      => $M_PRE]),
                          e_assign->new(["m_count"      => $trp]),
                          ],
                     }),
                 ], # end WAIT
         $M_PRE       => # You must assign m_next/m_count before entering this
         [
          e_assign->news
          (
           ["m_state" => $M_WAIT],
           ["m_addr"  => "{".$WSA->{sdram_addr_width}."{1'b1}}"]
           ),
          e_if->new
          ({
              comment   => " precharge all if arf, else precharge csn_decode",
              condition => "refresh_request",
              then      => ["m_cmd" => "{".$ALL.",".$PRECHARGE."}"],
              else      => ["m_cmd" => "{csn_decode,".$PRECHARGE."}"],
          }),
          ], # end PREcharge
         $M_REF       =>
         [
          e_assign->new(["ack_refresh_request"  => "1'b1"]),
          e_assign->new(["m_state"      => $M_WAIT]),
          e_assign->new(["m_cmd"        => "{".$ALL.",".$REFRESH."}"]),
          e_assign->new(["m_count"      => $trfc]),
          e_assign->new(["m_next"       => $M_IDLE]),
          ], # end REFresh
         default  =>
         [
          e_assign->new(["m_state"      => "m_state"]),
          e_assign->new(["m_cmd"        => $none_and_inhibit]),
          e_assign->new(["f_pop"        => "1'b0"]),
          e_assign->new(["oe"           => "1'b0"]),
          ],
         );
    
    my $m_open_recovery_list = [];
    my $m_refresh_recovery_list = [];
    my $m_max_recovery_time  = (&max ( ($twr - 1), ($cas_latency - 2), 0 ));
    if ($m_max_recovery_time > 0)
    {
        $m_open_recovery_list = [ 
                                  e_assign->news
                                  (
                                   ["m_state"   => $M_REC],
                                   ["m_next"    => $M_IDLE],
                                   ["m_count"   => $m_max_recovery_time],
                                   ),
                                  ];
        $m_refresh_recovery_list=[
                                  e_assign->news
                                  (
                                   ["m_state"   => $M_WAIT],
                                   ["m_next"    => $M_IDLE],
                                   ["m_count"   => $m_max_recovery_time],
                                   ),
                                  ];
    }
    else
    {
        $m_open_recovery_list = [ 
                                  e_assign->news
                                  (
                                   ["m_state"   => $M_PRE],
                                   ["m_next"    => $M_IDLE],
                                   ["m_count"   => $trp],
                                   ),
                                  ];
        $m_refresh_recovery_list=[
                                  e_assign->news
                                  (
                                   ["m_state"   => $M_IDLE],
                                   ),
                                  ];
    }

    if ($tristate_bridge_mode == 1) {
        $m_contents_hash{$M_WAIT} =
            [




             e_if->new
             ({
                 comment => " wait for tristate bridge",
                 condition => "!tz_waitrequest",
                 then => [
                          e_if->new
                          ({
                              comment   => " arf ? prechrg all : prechrg csn",
                              condition => "(m_next == $M_REF)",
                              then      => ["m_cmd"=>"{".$ALL.",".$NOP."}"],
                              else      => ["m_cmd"=>"{csn_decode,".$NOP."}"],
                          }),
                          e_if->new
                          ({
                              comment => " Count down til safe to Proceed...",
                              condition => "m_count > 1",
                              then => ["m_count" => "m_count - 1'b1"],
                              else => ["m_state" => "m_next"],
                          }),
                          ],
             }),
             ]; # end WAIT
        $m_contents_hash{$M_RD} = # Read: this is the exciting state 

            [ 



              e_assign->news
              (
               ["m_cmd"  => "{csn_decode,".$READ."}"],
               ["m_bank" => "f_select ? f_bank : active_bank"],
               ["m_dqm"  => "f_select ? f_dqm  : active_dqm"],
               ["m_addr" => "cas_addr"],
               ),
              e_if->new
              ({
                  comment => "Do we have a transaction pending?",
                  condition => "pending",
                  then =>
                      [
                       e_if->new
                       ({
                           comment => "if we need to arf, bail out, else spin",
                           condition => "refresh_request",
                           then => 
                               [
                                e_assign->news
                                (

                                 ["m_state"     => $M_WAIT],
                                 ["m_next"      => $M_IDLE],
                                 ["m_count"     => ($cas_latency - 1)],
                                 ),
                                ], # end refresh_req
                           else => # !refresh_req
                               [ # pop fifo, stay in same state!
                                 e_assign->news
                                 (
                                  ["f_pop"      => "1'b1"],
                                  ["active_cs_n"        => "f_cs_n"],
                                  ["active_rnw" => "f_rnw"],
                                  ["active_addr"        => "f_addr"],
                                  ["active_data"        => "f_data"],
                                  ["active_dqm" => "f_dqm"],
                                  ),
                                 ], # end !refresh_req
                             }), # end if refresh_req
                       ], # end pending
                  else => # !pending
                      [
                       e_if->new
                       ({
                           comment => "correctly end RD spin cycle if fifo mt",
                           condition => "~pending & f_pop",
                           then => ["m_cmd" => "{csn_decode,".$NOP."}"],
                       }),
                       e_assign->news
                       (
                        ["m_state"      => $M_REC],
                        ["m_next"       => $M_IDLE],
                        ["m_count"      => ($cas_latency - 1)],
                        ),
                       ], # end !pending
                   }), # end if pending
              ]; # end RD
        $m_contents_hash{$M_WR} = # Write: this is the exciting state where

            [ 



              e_assign->news
              (
               ["m_cmd"  => "{csn_decode,".$WRITE."}"],
               ["oe"     => "1'b1"],
               ["m_data" => "f_select ? f_data : active_data"],
               ["m_dqm"  => "f_select ? f_dqm  : active_dqm"],
               ["m_bank" => "f_select ? f_bank : active_bank"],
               ["m_addr" => "cas_addr"],
               ),
              e_if->new
              ({
                  comment => "Do we have a transaction pending?",
                  condition => "pending",
                  then =>
                      [
                       e_if->new
                       ({
                           comment => "if we need to ARF, bail out, else spin",
                           condition => "refresh_request",
                           then => 
                               [
                                e_assign->news
                                (

                                 ["m_state"     => $M_WAIT],
                                 ["m_next"      => $M_IDLE],
                                 ["m_count"     => $twr],
                                 ),
                                ], # end refresh_req
                           else => # !refresh_req
                               [ # pop fifo, stay in same state!
                                 e_assign->news
                                 (
                                  ["f_pop"      => "1'b1"],
                                  ["active_cs_n"        => "f_cs_n"],
                                  ["active_rnw" => "f_rnw"],
                                  ["active_addr"        => "f_addr"],
                                  ["active_data"        => "f_data"],
                                  ["active_dqm" => "f_dqm"],
                                  ),
                                 ], # end !refresh_req
                             }), # end if refresh_req
                       ], # end pending
                  else =>
                  [
                   e_if->new
                   ({
                       comment => "correctly end WR spin cycle if fifo empty",
                       condition => "~pending & f_pop",
                       then =>
                           [
                            e_assign->news
                            (
                             ["m_cmd"   => "{csn_decode,".$NOP."}"],
                             ["oe"      => "1'b0"],
                             ),
                            ],
                        }),
                   e_assign->news
                   (
                    ["m_state"  => $M_REC],
                    ["m_next"   => $M_IDLE],
                    ["m_count"  => $twr],
                    ),
                   ], # end !pending
               }), # end if pending
              ]; # end WR
    }
    else # optimize for direct control of sdram pins (no tri-state sharing)
    {
        $m_contents_hash{$M_WAIT} =
            [


             e_if->new
             ({
                 comment   => " precharge all if arf, else precharge csn_decode",
                 condition => "(m_next == $M_REF)",
                 then      => ["m_cmd" => "{".$ALL.",".$NOP."}"],
                 else      => ["m_cmd" => "{csn_decode,".$NOP."}"],
             }),