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attempt to fix bus

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This commit is contained in:
Raphael Jacquot 2019-02-06 17:50:36 +01:00
parent b8fa3b2df0
commit 3c32cbc213
1 changed files with 13 additions and 14 deletions
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27
saturn_core.v
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@ -103,7 +103,7 @@ module hp48_io_ram (
input [3:0] command,
input [3:0] nibble_in,
output reg [3:0] nibble_out,
output io_ram_active,
output reg io_ram_active,
output reg io_ram_error
);
@ -118,7 +118,7 @@ reg [19:0] base_addr;
reg [19:0] pc_ptr;
reg [19:0] data_ptr;
reg [3:0] io_ram [0:IO_RAM_LEN-1];
wire io_ram_active;
/*
*
*
@ -164,13 +164,12 @@ initial
*/
always @(*)
case (command)
`BUSCMD_PC_READ, `BUSCMD_DP_READ,
`BUSCMD_PC_WRITE, `BUSCMD_PC_WRITE:
begin
io_ram_active = 0;
if ((command==`BUSCMD_PC_READ)|(command==`BUSCMD_DP_READ)|
(command==`BUSCMD_PC_WRITE)|(command==`BUSCMD_PC_WRITE))
io_ram_active = ((base_addr>=data_ptr)&(data_ptr<base_addr+IO_RAM_LEN))&(configured);
default:
io_ram_active = 0;
endcase
end
always @(negedge clk)
if ((~reset)&(~io_ram_error))
@ -186,10 +185,10 @@ always @(negedge clk)
$display("io_ram: PC_READ %5h %h | OK", data_ptr, nibble_in);
`endif
end
`ifdef SIM
else
$display("io_ram: PC_READ %5h %h | NOK - IO_RAM not active (conf: %b)", data_ptr, nibble_in, configured);
`endif
// `ifdef SIM
// else
// $display("io_ram: PC_READ %5h %h | NOK - IO_RAM not active (conf: %b)", data_ptr, nibble_in, configured);
// `endif
pc_ptr <= pc_ptr + 1;
end
`BUSCMD_DP_WRITE:
@ -256,7 +255,7 @@ module hp48_bus (
input [3:0] command,
input [3:0] nibble_in,
output reg [3:0] nibble_out,
output bus_error
output reg bus_error
);
// io_ram
@ -291,13 +290,13 @@ hp48_rom dev_rom (
always @(*)
begin
bus_error = io_ram_error;
nibble_out = 0;
if ((command == `BUSCMD_PC_READ)|(command == `BUSCMD_DP_READ))
begin
if (io_ram_active) nibble_out = io_ram_nibble_out;
if (~io_ram_active) nibble_out = rom_nibble_out;
end
bus_error = io_ram_error;
end
endmodule