diff options
Diffstat (limited to 'm6522_tb.vhd')
| -rw-r--r-- | m6522_tb.vhd | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/m6522_tb.vhd b/m6522_tb.vhd new file mode 100644 index 0000000..7c4b1fa --- /dev/null +++ b/m6522_tb.vhd @@ -0,0 +1,323 @@ +library IEEE;
+use IEEE.STD_LOGIC_1164.ALL;
+use IEEE.NUMERIC_STD.ALL;
+
+entity m6522_tb is
+end entity;
+
+architecture tb of m6522_tb is
+
+component M6522 is
+ port (
+
+ I_RS : in std_logic_vector(3 downto 0);
+ I_DATA : in std_logic_vector(7 downto 0);
+ O_DATA : out std_logic_vector(7 downto 0);
+ O_DATA_OE_L : out std_logic;
+
+ I_RW_L : in std_logic;
+ I_CS1 : in std_logic;
+ I_CS2_L : in std_logic;
+
+ O_IRQ_L : out std_logic; -- note, not open drain
+ -- port a
+ I_CA1 : in std_logic;
+ I_CA2 : in std_logic;
+ O_CA2 : out std_logic;
+ O_CA2_OE_L : out std_logic;
+
+ I_PA : in std_logic_vector(7 downto 0);
+ O_PA : out std_logic_vector(7 downto 0);
+ O_PA_OE_L : out std_logic_vector(7 downto 0);
+
+ -- port b
+ I_CB1 : in std_logic;
+ O_CB1 : out std_logic;
+ O_CB1_OE_L : out std_logic;
+
+ I_CB2 : in std_logic;
+ O_CB2 : out std_logic;
+ O_CB2_OE_L : out std_logic;
+
+ I_PB : in std_logic_vector(7 downto 0);
+ O_PB : out std_logic_vector(7 downto 0);
+ O_PB_OE_L : out std_logic_vector(7 downto 0);
+
+ I_P2_H : in std_logic; -- high for phase 2 clock ____----__
+ RESET_L : in std_logic;
+ ENA_4 : in std_logic; -- clk enable
+ CLK : in std_logic
+ );
+end component;
+
+signal rs : std_logic_vector(3 downto 0) := "0000";
+signal di : std_logic_vector(7 downto 0) := "00000000";
+signal do : std_logic_vector(7 downto 0);
+signal n_d_oe : std_logic;
+signal r_nw : std_logic := '1';
+signal cs1 : std_logic := '0';
+signal n_cs2 : std_logic := '0';
+signal n_irq : std_logic;
+signal ca1_in : std_logic := '0';
+signal ca2_in : std_logic := '0';
+signal ca2_out : std_logic;
+signal n_ca2_oe : std_logic;
+signal pa_in : std_logic_vector(7 downto 0) := "00000000";
+signal pa_out : std_logic_vector(7 downto 0);
+signal n_pa_oe : std_logic_vector(7 downto 0);
+signal cb1_in : std_logic := '0';
+signal cb1_out : std_logic;
+signal n_cb1_oe : std_logic;
+signal cb2_in : std_logic := '0';
+signal cb2_out : std_logic;
+signal n_cb2_oe : std_logic;
+signal pb_in : std_logic_vector(7 downto 0) := "00000000";
+signal pb_out : std_logic_vector(7 downto 0);
+signal n_pb_oe : std_logic_vector(7 downto 0);
+
+signal phase2 : std_logic := '0';
+signal n_reset : std_logic := '0';
+signal clken : std_logic := '0';
+signal clock : std_logic := '0';
+
+begin
+
+ uut: m6522 port map (
+ rs, di, do, n_d_oe,
+ r_nw, cs1, n_cs2, n_irq,
+ ca1_in, ca2_in, ca2_out, n_ca2_oe,
+ pa_in, pa_out, n_pa_oe,
+ cb1_in, cb1_out, n_cb1_oe,
+ cb2_in, cb2_out, n_cb2_oe,
+ pb_in, pb_out, n_pb_oe,
+ phase2, n_reset, clken, clock
+ );
+
+ clock <= not clock after 125 ns; -- 4x 1 MHz
+ phase2 <= not phase2 after 500 ns;
+ clken <= '1'; -- all cycles enabled
+
+ process
+ begin
+ wait for 1 us;
+ -- Release reset
+ n_reset <= '1';
+ end process;
+
+ process
+
+ procedure reg_write(
+ a : in std_logic_vector(3 downto 0);
+ d : in std_logic_vector(7 downto 0)) is
+ begin
+ wait until falling_edge(phase2);
+ rs <= a;
+ di <= d;
+ cs1 <= '1';
+ r_nw <= '0';
+ wait until falling_edge(phase2);
+ cs1 <= '0';
+ r_nw <= '1';
+ end procedure;
+
+ procedure reg_read(
+ a : in std_logic_vector(3 downto 0)) is
+ begin
+ wait until falling_edge(phase2);
+ rs <= a;
+ cs1 <= '1';
+ r_nw <= '1';
+ wait until falling_edge(phase2);
+ cs1 <= '0';
+ end procedure;
+
+ begin
+ wait for 2 us;
+
+ -- Set port A and B to output
+ reg_write("0010","11111111");
+ reg_write("0011","11111111");
+
+ -- Write to port B
+ reg_write("0000","10101010");
+ -- Write to port B
+ reg_write("0000","01010101");
+ -- Write to port A (no handshake)
+ reg_write("1111","10101010");
+ -- Write to port A (with handshake)
+ reg_write("0001","01010101");
+
+ -- Set port A and B to input
+ reg_write("0010","00000000");
+ reg_write("0011","00000000");
+
+ -- Apply input stimuli and read from ports
+ pa_in <= "10101010";
+ pb_in <= "01010101";
+ reg_read("0000");
+ reg_read("0001");
+
+ -- Test CA1 interrupt
+ ca1_in <= '0';
+ reg_write("1100","00000001"); -- PCR - interrupt on rising edge
+ reg_write("1101","01111111"); -- Clear interrupts
+ reg_write("1110","01111111"); -- Disable all interrupts
+ reg_write("1110","10000010"); -- Enable CA1 interrupt
+ ca1_in <= '1'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("0001"); -- Should clear interrupt
+ wait for 2 us;
+ reg_write("1100","00000000"); -- PCR - interrupt on falling edge
+ ca1_in <= '0'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_write("1101","00000010"); -- Should clear interrupt
+ wait for 2 us;
+ reg_write("1110","00000010"); -- Disable CA1 interrupt
+
+ -- Test CB1 interrupt
+ cb1_in <= '0';
+ reg_write("1100","00010000"); -- PCR - interrupt on rising edge
+ reg_write("1101","01111111"); -- Clear interrupts
+ reg_write("1110","01111111"); -- Disable all interrupts
+ reg_write("1110","10010000"); -- Enable CB1 interrupt
+ cb1_in <= '1'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("0000"); -- Should clear interrupt
+ wait for 2 us;
+ reg_write("1100","00000000"); -- PCR - interrupt on falling edge
+ cb1_in <= '0'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_write("1101","00010000"); -- Should clear interrupt
+ wait for 2 us;
+ reg_write("1110","00010000"); -- Disable CA1 interrupt
+
+ -- Test CA2 interrupt modes
+ reg_write("1101","01111111"); -- Clear interrupts
+ reg_write("1110","01111111"); -- Disable all interrupts
+ reg_write("1110","10000001"); -- Enable CA2 interrupt
+ -- mode 2 (+ve edge, clear on read/write)
+ reg_write("1100","00000100"); -- PCR
+ ca2_in <= '1'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("1111"); -- Should not clear interrupt
+ reg_read("0001"); -- Should clear interrupt
+ wait for 2 us;
+ -- mode 0 (-ve edge, clear on read/write)
+ reg_write("1100","00000000"); -- PCR
+ ca2_in <= '0'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("1111"); -- Should not clear interrupt
+ reg_read("0001"); -- Should clear interrupt
+ wait for 2 us;
+ -- mode 3 (+ve edge, don't clear on read/write)
+ reg_write("1100","00000110");
+ ca2_in <= '1'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("1111"); -- Should not clear interrupt
+ reg_read("0001"); -- Should not clear interrupt
+ reg_write("1101","00000001"); -- Should clear interrupt
+ wait for 2 us;
+ -- mode 1 (-ve edge, don't clear on read/write)
+ reg_write("1100","00000010");
+ ca2_in <= '0'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("1111"); -- Should not clear interrupt
+ reg_read("0001"); -- Should not clear interrupt
+ reg_write("1101","00000001"); -- Should clear interrupt
+ wait for 2 us;
+
+ -- Test CA2 output modes
+ -- mode 4 (set low on read/write of ORA, set high on CA1 interrupt edge)
+ reg_write("1100","00001000");
+ -- mode 5 (set low for 1 cycle on read/write ORA)
+ reg_write("1100","00001010");
+ -- mode 6 (held low)
+ reg_write("1100","00001100");
+ -- mode 7 (held high)
+ reg_write("1100","00001110");
+
+ -- Test CB2 interrupt modes
+ reg_write("1101","01111111"); -- Clear interrupts
+ reg_write("1110","01111111"); -- Disable all interrupts
+ reg_write("1110","10001000"); -- Enable CB2 interrupt
+ -- mode 2 (+ve edge, clear on read/write)
+ reg_write("1100","01000000"); -- PCR
+ cb2_in <= '1'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("0000"); -- Should clear interrupt
+ wait for 2 us;
+ -- mode 0 (-ve edge, clear on read/write)
+ reg_write("1100","00000000"); -- PCR
+ cb2_in <= '0'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("0000"); -- Should clear interrupt
+ wait for 2 us;
+ -- mode 3 (+ve edge, don't clear on read/write)
+ reg_write("1100","01100000");
+ cb2_in <= '1'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("0000"); -- Should not clear interrupt
+ reg_write("1101","00001000"); -- Should clear interrupt
+ wait for 2 us;
+ -- mode 1 (-ve edge, don't clear on read/write)
+ reg_write("1100","00100000");
+ cb2_in <= '0'; -- Trigger event
+ wait for 2 us;
+ reg_read("1101");
+ reg_read("0000"); -- Should not clear interrupt
+ reg_write("1101","00001000"); -- Should clear interrupt
+ wait for 2 us;
+
+ -- Test CB2 output modes
+ -- mode 4 (set low on read/write of ORA, set high on CA1 interrupt edge)
+ reg_write("1100","10000000");
+ -- mode 5 (set low for 1 cycle on read/write ORA)
+ reg_write("1100","10100000");
+ -- mode 6 (held low)
+ reg_write("1100","11000000");
+ -- mode 7 (held high)
+ reg_write("1100","11100000");
+
+ -- Timer 1 timeout
+ reg_write("1101","01111111"); -- Clear interrupts
+ reg_write("1110","01111111"); -- Disable all interrupts
+ reg_write("1110","11000000"); -- Enable timer 1 interrupt
+ -- Count to 16
+ reg_write("0100","00010000");
+ reg_write("0101","00000000");
+ wait for 50 us;
+ -- Count to 16
+ reg_write("0100","00010000");
+ reg_write("0101","00000000"); -- Should clear interrupt
+ wait for 50 us;
+ reg_read("0100"); -- Should clear interrupt
+
+ -- Timer 2 timeout
+ reg_write("1101","01111111"); -- Clear interrupts
+ reg_write("1110","01111111"); -- Disable all interrupts
+ reg_write("1110","10100000"); -- Enable timer 2 interrupt
+ -- Count to 16
+ reg_write("1000","00010000");
+ reg_write("1001","00000000");
+ wait for 50 us;
+ -- Count to 16
+ reg_write("1000","00010000");
+ reg_write("1001","00000000"); -- Should clear interrupt
+ wait for 50 us;
+ reg_read("1000"); -- Should clear interrupt
+
+ wait;
+ end process;
+
+end architecture;
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