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/*
* main_xula2.v
*
* Copyright: (C) 2013 LeafLabs, LLC
* License: MIT License (See LICENSE file)
* Author: Bryan Newbold <bnewbold@leaflabs.com>
* Date: October 2013
*
* This is the top-level module for the Xess Corp Xula 2 development board.
*
* TODO if using this as a template for another design:
* - use a clock buffer, even if sticking with 12mhz
*/
module main (
input wire clock_12mhz,
inout wire [31:0] chan,
inout wire chan_clk,
//// Flash and microSD I/O
output wire microsd_cs,
output wire flash_cs,
output wire flash_sclk,
output wire flash_mosi,
output wire flash_miso
);
wire reset = chan[0];
wire uart_rx = chan[17];
wire uart_tx = chan[18];
reg [22:0] throb_counter = 0;
reg throb_led = 0;
assign chan[10] = throb_led;
wire [7:0] rx_byte;
wire [7:0] tx_byte;
wire uart_flag;
simple_uart #(
.CLOCK_DIVIDE(313) // for 12MHz clock
) simple_uart_inst (
.clk(clock_12mhz),
.rst(reset),
.rx(chan[17]),
.tx(chan[18]),
.transmit(uart_flag),
.tx_byte(tx_byte),
.received(uart_flag),
.rx_byte(rx_byte),
.is_receiving(),
.is_transmitting(),
.recv_error()
);
rot13 rot13_inst (
.clock(clock_12mhz),
.reset(reset),
.in_char(rx_byte),
.out_char(tx_byte)
);
always @(posedge clock_12mhz) begin
if (reset) begin
throb_counter <= 0;
throb_led <= 0;
end else begin
if (throb_counter >= 23'd06_000_000) begin
throb_led <= !throb_led;
throb_counter <= 23'd0;
end else begin
throb_counter <= throb_counter + 23'd1;
end
end
end
// Tie off unused outputs
assign microsd_cs = 1'bZ;
assign flash_cs = 1'bZ;
assign flash_sclk = 1'bZ;
assign flash_mosi = 1'bZ;
assign flash_miso = 1'bZ;
assign chan[31] = 1'bz;
/*
assign chan[31:21] = 11'bZ;
assign chan[19:1] = 19'bZ;
assign chan_clk = 1'bZ;
*/
endmodule
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