github.com/lisper.cpus-pdp8
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brought rs232 to top

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brad
2010-04-14 23:41:35 +00:00
parent 6379274142
commit 6a67dce53a
9 changed files with 104 additions and 44 deletions
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29
rtl/pdp8_tt.v
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@@ -1,17 +1,20 @@
// PDP8 console emulation
// brad@heeltoe.com
//`define sim_time
`ifdef debug
`define debug_tt_int 1
//`define debug_tt_reg 1
//`define debug_tt_state 1
`define debug_tt_data 1
`endif
//`define sim_time
module pdp8_tt(clk, brgclk, reset,
iot, state, mb,
io_data_in, io_data_out, io_select, io_selected,
io_data_avail, io_interrupt, io_skip);
io_data_avail, io_interrupt, io_skip,
uart_in, uart_out);
input clk;
input brgclk;
@@ -22,15 +25,17 @@ module pdp8_tt(clk, brgclk, reset,
input [11:0] mb;
input [11:0] io_data_in;
input [5:0] io_select;
input uart_in;
output reg [11:0] io_data_out;
output reg io_selected;
output io_data_avail;
output io_interrupt;
output reg io_skip;
output uart_out;
// internal state
reg [11:0] tx_data;
reg [7:0] tx_data;
reg tx_int;
wire tx_empty;
wire tx_ack;
@@ -80,7 +85,7 @@ module pdp8_tt(clk, brgclk, reset,
.tx_clk(uart_tx_clk),
.tx_req(tto_req),
.tx_ack(tx_ack),
.tx_data(tx_data[7:0]),
.tx_data(tx_data),
.tx_empty(tx_empty),
.rx_clk(uart_rx_clk),
@@ -96,14 +101,17 @@ module pdp8_tt(clk, brgclk, reset,
.tx_clk(uart_tx_clk),
.tx_req(tto_req),
.tx_ack(tx_ack),
.tx_data(tx_data[7:0]),
.tx_data(tx_data),
.tx_empty(tx_empty),
.rx_clk(uart_rx_clk),
.rx_req(tti_req),
.rx_ack(rx_ack),
.rx_data(rx_data[7:0]),
.rx_empty(rx_empty));
.rx_empty(rx_empty),
.rx_in(uart_in),
.tx_out(uart_out));
`endif
// interrupt output
@@ -114,7 +122,8 @@ module pdp8_tt(clk, brgclk, reset,
assign rx_data[11:8] = 4'b0;
// combinatorial
always @(state or rx_int or tx_int)
always @(state or iot or io_select or mb or
rx_int or tx_int or io_data_in or rx_data)
begin
// sampled during f1
io_skip = 1'b0;
@@ -171,7 +180,7 @@ module pdp8_tt(clk, brgclk, reset,
rx_int <= 0;
tx_int <= 0;
tx_data <= 0;
tx_data <= 8'b0;
end
else
begin
@@ -206,7 +215,7 @@ module pdp8_tt(clk, brgclk, reset,
end
if (mb[2])
begin
tx_data <= io_data_in;
tx_data <= io_data_in[7:0];
`ifdef debug_tt_data
$display("xxx tx_data %o", io_data_in);
`endif