display: nul-byte schreiben ist boese. gehoert noch schoener gefixt

diff --git a/src/display.vhd b/src/display.vhd
index 432c07a6f84880b533fbb0fafafdbe8f90a83b5d..3a3aac17a79e31ab05a2d9ebdb4de9a42829a652 100644 (file)
--- a/src/display.vhd
+++ b/src/display.vhd
@@ -65,7 +65,8 @@ begin
        end process;
 
        -- next state
-       process(state_int, d_new_result, d_new_eingabe, d_done, free, d_spalte_int)
+       process(state_int, d_new_result, d_new_eingabe, d_done, free, d_spalte_int,
+               d_char)
        begin
                state_next <= state_int;
 
@@ -86,7 +87,7 @@ begin
                                        state_next <= S_PUTCH;
                                end if;
                        when S_PUTCH =>
-                               if free = '0' then
+                               if free = '0' or (free = '1' and d_char = x"00") then
                                        state_next <= S_WAIT;
                                end if;
                        when S_WAIT =>
@@ -131,8 +132,10 @@ begin
                        when S_GETCH =>
                                d_get_next <= '1';
                        when S_PUTCH =>
-                               command_next <= COMMAND_SET_CHAR;
-                               command_data_next <= x"ffffff" & std_logic_vector(d_char);
+                               if d_char /= x"00" then
+                                       command_next <= COMMAND_SET_CHAR;
+                                       command_data_next <= x"ffffff" & std_logic_vector(d_char);
+                               end if;
                        when S_WAIT | S_NOP1 =>
                                command_next <= COMMAND_NOP;
                                command_data_next <= x"00000000";