diff options
| -rw-r--r-- | zpu/hdl/zpu4/src/io.vhd | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/zpu/hdl/zpu4/src/io.vhd b/zpu/hdl/zpu4/src/io.vhd index e2576e2..a0e494a 100644 --- a/zpu/hdl/zpu4/src/io.vhd +++ b/zpu/hdl/zpu4/src/io.vhd @@ -38,6 +38,8 @@ signal serving : std_logic; file l_file : TEXT open write_mode is log_file;
constant lowAddrBits: std_logic_vector(minAddrBit-1 downto 0) := (others=>'0');
+constant tx_full: std_logic := '0';
+constant rx_empty: std_logic := '1';
begin
@@ -86,11 +88,11 @@ begin --<JK> extend compare to avoid waring messages
if ("1" & addr & lowAddrBits)=x"80a000c" then
report "Read UART[0]";
- read(8) <= '0'; -- output fifo not full
- read(9) <= '1'; -- receiver not empty
+ read(8) <= not tx_full; -- output fifo not full
+ read(9) <= not rx_empty; -- receiver not empty
elsif ("1" & addr & lowAddrBits)=x"80a0010" then
report "Read UART[1]";
- read(8) <= '1'; -- receiver not empty
+ read(8) <= not rx_empty; -- receiver not empty
read(7 downto 0) <= (others => '0');
elsif addr(12)='1' then
report "Read TIMER";
|
