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Updated 6809 clocking scheme; tested on Dragon 32 and Simple 6809; fixed 6809 reset command bug; version now 0.64

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Change-Id: Id772f50d3676b057ed31c001b211fdf92a9f49f8
This commit is contained in:
David Banks 2015-08-08 13:49:13 +01:00
parent aeed6c1a65
commit d44d3a889e
3 changed files with 59 additions and 22 deletions
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MC6809CpuMon.bit
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2
firmware/AtomBusMon.c
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@ -10,7 +10,7 @@
* VERSION and NAME are used in the start-up message
********************************************************/
#define VERSION "0.63"
#define VERSION "0.64"
#if (CPU == Z80)
#define NAME "ICE-T80"

79
src/MC6809ECpuMon.vhd
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@ -44,12 +44,11 @@ entity MC6809ECpuMon is
PIN34 : inout std_logic;
PIN35 : inout std_logic;
PIN36 : inout std_logic;
PIN37 : inout std_logic;
PIN38 : inout std_logic;
PIN39 : in std_logic;
-- Signals common to both 6809 and 6809E
RES_n : inout std_logic;
RES_n : in std_logic;
NMI_n : in std_logic;
IRQ_n : in std_logic;
FIRQ_n : in std_logic;
@ -97,7 +96,7 @@ signal R_W_n_int : std_logic;
signal NMI_sync : std_logic;
signal IRQ_sync : std_logic;
signal FIRQ_sync : std_logic;
signal RES_sync : std_logic;
signal nRST_sync : std_logic;
signal HALT_sync : std_logic;
signal Addr_int : std_logic_vector(15 downto 0);
signal Din : std_logic_vector(7 downto 0);
@ -108,7 +107,10 @@ signal hold : std_logic;
signal memory_rd : std_logic;
signal memory_wr : std_logic;
signal memory_rd1 : std_logic;
signal memory_wr1 : std_logic;
signal memory_addr : std_logic_vector(15 downto 0);
signal memory_addr1 : std_logic_vector(15 downto 0);
signal memory_dout : std_logic_vector(7 downto 0);
signal memory_din : std_logic_vector(7 downto 0);
signal memory_done : std_logic;
@ -137,7 +139,15 @@ signal E : std_logic;
signal DMA_n_BREQ_n : std_logic;
signal clock7_3728 : std_logic;
signal E_a : std_logic; -- E delayed by 0..20ns
signal E_b : std_logic; -- E delayed by 20..40ns
signal E_c : std_logic; -- E delayed by 40..60ns
signal E_d : std_logic; -- E delayed by 60..80ns
signal E_e : std_logic; -- E delayed by 80..100ns
signal data_wr : std_logic;
signal nRSTout : std_logic;
begin
mon : entity work.BusMonCore
@ -155,8 +165,8 @@ begin
WrIO_n => '1',
Sync => Sync_int,
Rdy => Rdy_int,
nRSTin => RES_n,
nRSTout => RES_n,
nRSTin => nRST_sync,
nRSTout => nRSTout,
CountCycle => CountCycle,
trig => trig,
lcd_rs => open,
@ -215,7 +225,7 @@ begin
GenCPU09Core: if UseCPU09Core generate
inst_cpu09: entity work.cpu09 port map (
clk => cpu_clk,
rst => RES_sync,
rst => not nRST_sync,
vma => AVMA,
lic_out => LIC,
ifetch => ifetch,
@ -243,7 +253,7 @@ begin
NMI_sync <= not NMI_n;
IRQ_sync <= not IRQ_n;
FIRQ_sync <= not FIRQ_n;
RES_sync <= not RES_n;
nRST_sync <= RES_n and nRSTout;
HALT_sync <= not HALT_n;
end if;
end process;
@ -279,29 +289,41 @@ begin
-- Only count cycles when the 6809 is actually running
CountCycle <= not hold;
-- this block delays memory_rd, memory_wr, memory_addr until the start of the next cpu clk cycle
-- necessary because the cpu mon block is clocked of the opposite edge of the clock
-- this allows a full cpu clk cycle for cpu mon reads and writes
mem_gen : process(cpu_clk)
begin
if rising_edge(cpu_clk) then
memory_rd1 <= memory_rd;
memory_wr1 <= memory_wr;
memory_addr1 <= memory_addr;
end if;
end process;
R_W_n <= 'Z' when TSC = '1' else
'1' when memory_rd = '1' else
'0' when memory_wr = '1' else
'1' when memory_rd1 = '1' else
'0' when memory_wr1 = '1' else
R_W_n_int;
Addr <= (others => 'Z') when TSC = '1' else
memory_addr when (memory_rd = '1' or memory_wr = '1') else
memory_addr1 when (memory_rd1 = '1' or memory_wr1 = '1') else
Addr_int;
data_latch : process(E)
begin
if falling_edge(E) then
Din <= Data;
end if;
memory_din <= Data;
end if;
end process;
memory_din <= Data;
Data <= memory_dout when TSC = '0' and E = '1' and memory_wr = '1' else
Dout when TSC = '0' and E = '1' and R_W_n_int = '0' and memory_rd = '0' else
Data <= memory_dout when TSC = '0' and data_wr = '1' and memory_wr1 = '1' else
Dout when TSC = '0' and data_wr = '1' and R_W_n_int = '0' and memory_rd1 = '0' else
(others => 'Z');
memory_done <= memory_rd or memory_wr;
memory_done <= memory_rd1 or memory_wr1;
-- The following outputs are not implemented
-- BUSY (6809E mode)
@ -334,9 +356,24 @@ begin
-- 7.3728 MHz in Normal Mode (6809) so it can drive EXTAL (PIN38)
clock_test <= clk_count(1) when EMode_n = '0' else clock7_3728;
-- Delayed version of the E clock
-- E_e is delayed by 80-100ns which is a close approximation to the real 6809
-- E_c is delayed by 40-60ns which is used to provide extra data hold time on writes
e_gen : process(clock49)
begin
if rising_edge(clock49) then
E_a <= E;
E_b <= E_a;
E_c <= E_b;
E_d <= E_c;
E_e <= E_d;
end if;
end process;
-- Main clocks
cpu_clk <= Q;
busmon_clk <= E;
cpu_clk <= not E_e;
busmon_clk <= E_e;
data_wr <= E_c;
-- Quadrature clock generator, unused in 6809E mode
quadrature_gen : process(EXTAL)