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Diffstat (limited to 'fpga/usrp2/control_lib/quad_uart.v')
| -rw-r--r-- | fpga/usrp2/control_lib/quad_uart.v | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/fpga/usrp2/control_lib/quad_uart.v b/fpga/usrp2/control_lib/quad_uart.v new file mode 100644 index 000000000..39998150d --- /dev/null +++ b/fpga/usrp2/control_lib/quad_uart.v @@ -0,0 +1,88 @@ +// +// Copyright 2011 Ettus Research LLC +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. +// + + +module quad_uart + #(parameter TXDEPTH = 1, + parameter RXDEPTH = 1) + (input clk_i, input rst_i, + input we_i, input stb_i, input cyc_i, output reg ack_o, + input [4:0] adr_i, input [31:0] dat_i, output reg [31:0] dat_o, + output [3:0] rx_int_o, output [3:0] tx_int_o, + output [3:0] tx_o, input [3:0] rx_i, output [3:0] 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[0:3]; + wire [7:0] rx_char[0:3]; + wire [3:0] tx_fifo_full, rx_fifo_empty; + wire [7:0] tx_fifo_level[0:3], rx_fifo_level[0:3]; + + always @(posedge clk_i) + if (rst_i) + ack_o <= 1'b0; + else + ack_o <= wb_acc & ~ack_o; + + integer i; + always @(posedge clk_i) + if (rst_i) + for(i=0;i<4;i=i+1) + clkdiv[i] <= 0; + else if (wb_wr) + case(adr_i[2:0]) + SUART_CLKDIV : clkdiv[adr_i[4:3]] <= dat_i[15:0]; + endcase // case(adr_i) + + always @(posedge clk_i) + case (adr_i[2:0]) + SUART_TXLEVEL : dat_o <= tx_fifo_level[adr_i[4:3]]; + SUART_RXLEVEL : dat_o <= rx_fifo_level[adr_i[4:3]]; + SUART_RXCHAR : dat_o <= rx_char[adr_i[4:3]]; + endcase // case(adr_i) + + genvar j; + generate + for(j=0;j<4;j=j+1) + begin : gen_uarts + simple_uart_tx #(.DEPTH(TXDEPTH)) simple_uart_tx + (.clk(clk_i),.rst(rst_i), + .fifo_in(dat_i[7:0]),.fifo_write(ack_o && wb_wr && (adr_i[2:0] == SUART_TXCHAR) && (adr_i[4:3]==j)), + .fifo_level(tx_fifo_level[j]),.fifo_full(tx_fifo_full[j]), + .clkdiv(clkdiv[j]),.baudclk(baud_o[j]),.tx(tx_o[j])); + + simple_uart_rx #(.DEPTH(RXDEPTH)) simple_uart_rx + (.clk(clk_i),.rst(rst_i), + .fifo_out(rx_char[j]),.fifo_read(ack_o && ~wb_wr && (adr_i[2:0] == SUART_RXCHAR) && (adr_i[4:3]==j)), + .fifo_level(rx_fifo_level[j]),.fifo_empty(rx_fifo_empty[j]), + .clkdiv(clkdiv[j]),.rx(rx_i[j])); + end // block: gen_uarts + endgenerate + + assign tx_int_o = ~tx_fifo_full; // Interrupt for those that have space + assign rx_int_o = ~rx_fifo_empty; // Interrupt for those that have data + +endmodule // quad_uart |