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[/] [s6soc/] [trunk/] [rtl/] [toplevel.v] - Rev 47
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`timescale 10ns / 100ps //////////////////////////////////////////////////////////////////////////////// // // Filename: toplevel.v // // Project: CMod S6 System on a Chip, ZipCPU demonstration project // // Purpose: This is (supposed to be) the one Xilinx specific file in the // project. The idea is that all of the board specific logic, // the logic used in simulation, is kept in the busmaster.v file. It's // not quite true, since rxuart and txuart modules are instantiated here, // but it's mostly true. // // One thing that makes this module unique is that all of its inputs and // outputs must match those on the chip, as specified within the cmod.ucf // file (up one directory). // // Within this file you will find specific I/O for output pins, such as // the necessary adjustments to make an I2C port from GPIO pins, as well // as the clock management approach. // // // // Creator: Dan Gisselquist, Ph.D. // Gisselquist Technology, LLC // //////////////////////////////////////////////////////////////////////////////// // // Copyright (C) 2015-2016, Gisselquist Technology, LLC // // This program is free software (firmware): 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 MERCHANTIBILITY 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. (It's in the $(ROOT)/doc directory, run make with no // target there if the PDF file isn't present.) If not, see // <http://www.gnu.org/licenses/> for a copy. // // License: GPL, v3, as defined and found on www.gnu.org, // http://www.gnu.org/licenses/gpl.html // // //////////////////////////////////////////////////////////////////////////////// // // module toplevel(i_clk_8mhz, o_qspi_cs_n, o_qspi_sck, io_qspi_dat, i_btn, o_led, o_pwm, o_pwm_shutdown_n, o_pwm_gain, i_uart, o_uart, o_uart_rts_n, i_uart_cts_n, i_kp_row, o_kp_col, i_gpio, o_gpio, io_scl, io_sda); input i_clk_8mhz; // // Quad SPI Flash output wire o_qspi_cs_n; output wire o_qspi_sck; inout wire [3:0] io_qspi_dat; // // General purpose I/O input [1:0] i_btn; output wire [3:0] o_led; output wire o_pwm, o_pwm_shutdown_n, o_pwm_gain; // // and our serial port input i_uart; output wire o_uart; // and it's associated control wires output wire o_uart_rts_n; input i_uart_cts_n; // Our keypad input [3:0] i_kp_row; output wire [3:0] o_kp_col; // and our GPIO input [15:2] i_gpio; output wire [15:2] o_gpio; // and our I2C port inout io_scl, io_sda; // // Clock management // // Generate a usable clock for the rest of the board to run at. // wire ck_zero_0, clk_s; // Clock frequency = (20 / 2) * 8Mhz = 80 MHz // Clock period = 12.5 ns DCM_SP #( .CLKDV_DIVIDE(2.0), .CLKFX_DIVIDE(2), // Here's the divide by two .CLKFX_MULTIPLY(20), // and here's the multiply by 20 .CLKIN_DIVIDE_BY_2("FALSE"), .CLKIN_PERIOD(125.0), .CLKOUT_PHASE_SHIFT("NONE"), .CLK_FEEDBACK("1X"), .DESKEW_ADJUST("SYSTEM_SYNCHRONOUS"), .DLL_FREQUENCY_MODE("LOW"), .DUTY_CYCLE_CORRECTION("TRUE"), .PHASE_SHIFT(0), .STARTUP_WAIT("TRUE") ) u0( .CLKIN(i_clk_8mhz), .CLK0(ck_zero_0), .CLKFB(ck_zero_0), .CLKFX(clk_s), .PSEN(1'b0), .RST(1'b0)); // Baud rate is set by clock rate / baud rate desired. Thus, // 80 MHz / 9600 Baud = 8333, or about 0x208d. We choose a slow // speed such as 9600 Baud to help the CPU keep up with the serial // port rate. localparam [30:0] UART_SETUP = 31'h4000208d; // // BUSMASTER // // Busmaster is so named because it contains the wishbone // interconnect that all of the internal devices are hung off of. // To reconfigure this device for another purpose, usually // the busmaster module (i.e. the interconnect) is all that needs // to be changed: either to add more devices, or to remove them. // wire [3:0] qspi_dat; wire [1:0] qspi_bmod; wire [15:0] w_gpio; wire w_uart_rts_n; busmaster #(.UART_SETUP(UART_SETUP)) masterbus(clk_s, 1'b0, // Serial port wires i_uart, o_uart_rts_n, o_uart, i_uart_cts_n, // SPI/SD-card flash o_qspi_cs_n, o_qspi_sck, qspi_dat, io_qspi_dat, qspi_bmod, // Board lights and switches i_btn, o_led, o_pwm, { o_pwm_shutdown_n, o_pwm_gain }, // Keypad connections i_kp_row, o_kp_col, // GPIO lines { i_gpio, io_scl, io_sda }, w_gpio ); // // Quad SPI support // // Supporting a Quad SPI port requires knowing which direction the // wires are going at each instant, whether the device is in full // Quad mode in, full quad mode out, or simply the normal SPI // port with one wire in and one wire out. This utilizes our // control wires (qspi_bmod) to set the output lines appropriately. // assign io_qspi_dat = (~qspi_bmod[1])?({2'b11,1'bz,qspi_dat[0]}) :((qspi_bmod[0])?(4'bzzzz):(qspi_dat[3:0])); // // I2C support // // Supporting I2C requires a couple quick adjustments to our // GPIO lines. Specifically, we'll allow that when the output // (i.e. w_gpio) pins are high, then the I2C lines float. They // will be (need to be) pulled up by a resistor in order to // match the I2C protocol, but this change makes them look/act // more like GPIO pins. // assign io_sda = (w_gpio[0]) ? 1'bz : 1'b0; assign io_scl = (w_gpio[1]) ? 1'bz : 1'b0; assign o_gpio[15:2] = w_gpio[15:2]; endmodule
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