1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
//
// Copyright 2011 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
module simple_uart
#(parameter CLKDIV_DEFAULT = 16'd0, parameter RX_SIZE=8, parameter TX_SIZE=0)
(input clk_i, input rst_i,
input we_i, input stb_i, input cyc_i, output reg ack_o,
input [2:0] adr_i, input [31:0] dat_i, output reg [31:0] dat_o,
output rx_int_o, output tx_int_o, output tx_o, input rx_i, output baud_o);
// Register Map
localparam SUART_CLKDIV = 0;
localparam SUART_TXLEVEL = 1;
localparam SUART_RXLEVEL = 2;
localparam SUART_TXCHAR = 3;
localparam SUART_RXCHAR = 4;
wire wb_acc = cyc_i & stb_i; // WISHBONE access
wire wb_wr = wb_acc & we_i; // WISHBONE write access
reg [15:0] clkdiv;
wire [7:0] rx_char;
wire tx_fifo_full, rx_fifo_empty;
wire [15:0] tx_fifo_level, rx_fifo_level;
always @(posedge clk_i)
if (rst_i)
ack_o <= 1'b0;
else
ack_o <= wb_acc & ~ack_o;
always @(posedge clk_i)
if (rst_i)
clkdiv <= CLKDIV_DEFAULT;
else if (wb_wr)
case(adr_i)
SUART_CLKDIV : clkdiv <= dat_i[15:0];
endcase // case(adr_i)
always @(posedge clk_i)
case (adr_i)
SUART_TXLEVEL : dat_o <= tx_fifo_level;
SUART_RXLEVEL : dat_o <= rx_fifo_level;
SUART_RXCHAR : dat_o <= rx_char;
endcase // case(adr_i)
simple_uart_tx #(.SIZE(TX_SIZE)) simple_uart_tx
(.clk(clk_i),.rst(rst_i),
.fifo_in(dat_i[7:0]),.fifo_write(ack_o && wb_wr && (adr_i == SUART_TXCHAR)),
.fifo_level(tx_fifo_level),.fifo_full(tx_fifo_full),
.clkdiv(clkdiv),.baudclk(baud_o),.tx(tx_o));
simple_uart_rx #(.SIZE(RX_SIZE)) simple_uart_rx
(.clk(clk_i),.rst(rst_i),
.fifo_out(rx_char),.fifo_read(ack_o && ~wb_wr && (adr_i == SUART_RXCHAR)),
.fifo_level(rx_fifo_level),.fifo_empty(rx_fifo_empty),
.clkdiv(clkdiv),.rx(rx_i));
assign tx_int_o = ~tx_fifo_full;
assign rx_int_o = ~rx_fifo_empty;
endmodule // simple_uart
|
