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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] command,
input [3:0] nibble_in, input [3:0] nibble_in,
output reg [3:0] nibble_out, output reg [3:0] nibble_out,
output io_ram_active, output reg io_ram_active,
output reg io_ram_error output reg io_ram_error
); );
@ -118,7 +118,7 @@ reg [19:0] base_addr;
reg [19:0] pc_ptr; reg [19:0] pc_ptr;
reg [19:0] data_ptr; reg [19:0] data_ptr;
reg [3:0] io_ram [0:IO_RAM_LEN-1]; reg [3:0] io_ram [0:IO_RAM_LEN-1];
wire io_ram_active;
/* /*
* *
* *
@ -164,13 +164,12 @@ initial
*/ */
always @(*) always @(*)
case (command) begin
`BUSCMD_PC_READ, `BUSCMD_DP_READ, io_ram_active = 0;
`BUSCMD_PC_WRITE, `BUSCMD_PC_WRITE: 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); io_ram_active = ((base_addr>=data_ptr)&(data_ptr<base_addr+IO_RAM_LEN))&(configured);
default: end
io_ram_active = 0;
endcase
always @(negedge clk) always @(negedge clk)
if ((~reset)&(~io_ram_error)) if ((~reset)&(~io_ram_error))
@ -186,10 +185,10 @@ always @(negedge clk)
$display("io_ram: PC_READ %5h %h | OK", data_ptr, nibble_in); $display("io_ram: PC_READ %5h %h | OK", data_ptr, nibble_in);
`endif `endif
end end
`ifdef SIM // `ifdef SIM
else // else
$display("io_ram: PC_READ %5h %h | NOK - IO_RAM not active (conf: %b)", data_ptr, nibble_in, configured); // $display("io_ram: PC_READ %5h %h | NOK - IO_RAM not active (conf: %b)", data_ptr, nibble_in, configured);
`endif // `endif
pc_ptr <= pc_ptr + 1; pc_ptr <= pc_ptr + 1;
end end
`BUSCMD_DP_WRITE: `BUSCMD_DP_WRITE:
@ -256,7 +255,7 @@ module hp48_bus (
input [3:0] command, input [3:0] command,
input [3:0] nibble_in, input [3:0] nibble_in,
output reg [3:0] nibble_out, output reg [3:0] nibble_out,
output bus_error output reg bus_error
); );
// io_ram // io_ram
@ -291,13 +290,13 @@ hp48_rom dev_rom (
always @(*) always @(*)
begin begin
bus_error = io_ram_error;
nibble_out = 0; nibble_out = 0;
if ((command == `BUSCMD_PC_READ)|(command == `BUSCMD_DP_READ)) if ((command == `BUSCMD_PC_READ)|(command == `BUSCMD_DP_READ))
begin begin
if (io_ram_active) nibble_out = io_ram_nibble_out; if (io_ram_active) nibble_out = io_ram_nibble_out;
if (~io_ram_active) nibble_out = rom_nibble_out; if (~io_ram_active) nibble_out = rom_nibble_out;
end end
bus_error = io_ram_error;
end end
endmodule endmodule