// // Top level module for the FPGA on the MAX80 board by // Per Mårtensson and H. Peter Anvin // // This is for MAX80 as target on the ABC-bus. // // Sharing JTAG pins (via JTAGEN) `undef SHARED_JTAG module max80 #(parameter logic [6:1] x_mosfet, parameter logic [7:0] fpga_ver) ( // Clock oscillator input master_clk, // 336 MHz from PLL2 input slow_clk, // ~12 MHz clock from PLL2 input master_pll_locked, // PLL2 is locked, master_clk is good output reset_plls, // Reset all PLLs including PLL2 input board_id, // This better match the firmware // ABC-bus inout abc_clk, // ABC-bus 3 MHz clock inout [15:0] abc_a, // ABC address bus inout [7:0] abc_d, // ABC data bus output abc_d_oe, // Data bus output enable inout abc_rst_n, // ABC bus reset strobe inout abc_cs_n, // ABC card select strobe inout [4:0] abc_out_n, // OUT, C1-C4 strobe inout [1:0] abc_inp_n, // INP, STATUS strobe inout abc_xmemfl_n, // Memory read strobe inout abc_xmemw800_n, // Memory write strobe (ABC800) inout abc_xmemw80_n, // Memory write strobe (ABC80) inout abc_xinpstb_n, // I/O read strobe (ABC800) inout abc_xoutpstb_n, // I/O write strobe (ABC80) // The following are inverted versus the bus IF // the corresponding MOSFETs are installed inout abc_rdy_x, // RDY = WAIT# inout abc_resin_x, // System reset request inout abc_int80_x, // System INT request (ABC80) inout abc_int800_x, // System INT request (ABC800) inout abc_nmi_x, // System NMI request (ABC800) inout abc_xm_x, // System memory override (ABC800) // Host/device control output abc_host, // 1 = host, 0 = target // ABC-bus extension header // (Note: cannot use an array here because HC and HH are // input only.) inout exth_ha, inout exth_hb, input exth_hc, inout exth_hd, inout exth_he, inout exth_hf, inout exth_hg, input exth_hh, // SDRAM bus output sr_clk, output [1:0] sr_ba, // Bank address output [12:0] sr_a, // Address within bank inout [15:0] sr_dq, // Also known as D or IO output [1:0] sr_dqm, // DQML and DQMH output sr_cs_n, output sr_we_n, output sr_cas_n, output sr_ras_n, // SD card input sd_cd_n, output sd_cs_n, output sd_clk, output sd_di, input sd_do, // Serial console (naming is FPGA as DCE) input tty_txd, output tty_rxd, input tty_rts, output tty_cts, input tty_dtr, // SPI flash memory (also configuration) output flash_cs_n, output flash_sck, inout [1:0] flash_io, // SPI bus (connected to ESP32 so can be bidirectional) inout spi_clk, // ESP32 IO12 inout [1:0] spi_io, // ESP32 IO13,IO11 inout spi_cs_esp_n, // ESP32 IO10 inout spi_cs_flash_n, // ESP32 IO01 // Other ESP32 connections inout esp_io0, // ESP32 IO00 inout esp_int, // ESP32 IO09 // I2C bus (RTC and external) inout i2c_scl, inout i2c_sda, input rtc_32khz, input rtc_int_n, // LEDs output [2:0] led, // USB inout usb_dp, inout usb_dn, output usb_pu, input usb_rx, input usb_rx_ok, // HDMI output [2:0] hdmi_d, output hdmi_clk, inout hdmi_scl, inout hdmi_sda, inout hdmi_hpd, // Unconnected pins with pullups, used for randomness inout [2:0] rngio, // Various clocks available to the top level as well as internally output sdram_clk, // 168 MHz SDRAM clock output sys_clk, // 84 MHz System clock output flash_clk, // 134 MHz Serial flash ROM clock output usb_clk, // 48 MHz USB clock output vid_clk, // 56 MHz Video pixel clock output vid_hdmiclk // 280 MHz HDMI serializer clock = vid_clk x 5 ); // ----------------------------------------------------------------------- // PLLs and reset // ----------------------------------------------------------------------- reg rst_n = 1'b0; // Internal system reset reg hard_rst_n = 1'b0; // Strict POR reset only wire reconfig_rst; // Reconfigure FPGA assign reset_plls = 1'b0; tri1 [4:1] pll_locked; assign pll_locked[2] = master_pll_locked; fpgarst fpgarst ( .rst_n ( master_pll_locked ), .clk ( slow_clk ), .reconfig ( reconfig_rst ) ); // // Clocks. // // All clocks are derived from a common oscillator connected to an // input clock pin, which is a dedicated clock pin feeding into // hardware PLL2 and PLL4. The SDRAM clock output is a dedicated // clock out pin from PLL3. // // The input frequency is not consistent across board revisions, // so PLL2 is configured to produce a common master clock (336 MHz) // in the appropriate top level file. // // The following sets of clocks are closely tied and expected to // be synchronous, and therefore should come from the same PLL each; // furthermore, the design strictly assumes the ratios specified. // // sdram_clk, sys_clk - 2:1 ratio // vid_hdmiclk, vid_clk - 5:1 ratio // pll3 pll3 ( .areset ( ~pll_locked[2] ), .locked ( pll_locked[3] ), .inclk0 ( master_clk ), .c0 ( sr_clk ), // Output to clock pin (phase shift) .c1 ( sdram_clk ), // Internal logic/buffer data clock .c2 ( sys_clk ), .c3 ( flash_clk ), .c4 ( usb_clk ) ); pll4 pll4 ( .areset ( ~pll_locked[2] ), .locked ( pll_locked[4] ), .inclk0 ( master_clk ), .c0 ( vid_hdmiclk ), .c1 ( vid_clk ) ); wire all_plls_locked = &pll_locked; // // sys_clk pulse generation of various powers of two; allows us to // reuse the same counter for a lot of things that require periodic // timing events without strong requirements on the specific timing. // The first strobe is asserted 2^n cycles after rst_n goes high. // // The same counter is used to hold rst_n and hard_rst_n low for // 2^reset_pow2 cycles. // // XXX: reuse this counter for the CPU cycle counter. // localparam reset_pow2 = 12; reg [31:0] sys_clk_ctr; reg [31:0] sys_clk_ctr_q; reg [31:1] sys_clk_stb; // 3 types of reset: system, hard, and reconfig wire [3:1] cpu_reset_cmd; // CPU-originated reset command reg [3:1] cpu_reset_cmd_q[0:1]; wire [3:1] aux_reset_cmd; // Other reset sources reg [3:1] reset_cmd_q = 3'b0; assign reconfig_rst = reset_cmd_q[3]; always @(negedge all_plls_locked or posedge sys_clk) if (~all_plls_locked) begin hard_rst_n <= 1'b0; rst_n <= 1'b0; reset_cmd_q[2:1] <= 3'b0; cpu_reset_cmd_q[0] <= 3'b0; cpu_reset_cmd_q[1] <= 3'b0; sys_clk_ctr <= (-'sb1) << reset_pow2; sys_clk_ctr_q <= 'b0; sys_clk_stb <= 'b0; end else begin cpu_reset_cmd_q[0] <= cpu_reset_cmd; cpu_reset_cmd_q[1] <= cpu_reset_cmd_q[0]; reset_cmd_q <= (cpu_reset_cmd_q[0] & ~cpu_reset_cmd_q[1]) | aux_reset_cmd; // Reconfig reset is sticky until FPGA reloaded... reset_cmd_q[3] <= reset_cmd_q[3] | cpu_reset_cmd_q[0][3] | aux_reset_cmd[3]; if (|reset_cmd_q) begin // Soft or hard reset sys_clk_ctr <= (-'sb1) << reset_pow2; sys_clk_ctr_q <= 1'b0; sys_clk_stb <= 1'b0; rst_n <= 1'b0; hard_rst_n <= hard_rst_n & ~|reset_cmd_q[3:2]; end else begin sys_clk_ctr <= sys_clk_ctr + 1'b1; sys_clk_ctr_q <= ~rst_n ? 'b0 : sys_clk_ctr; sys_clk_stb <= ~sys_clk_ctr & sys_clk_ctr_q; rst_n <= rst_n | ~sys_clk_ctr[reset_pow2]; hard_rst_n <= hard_rst_n | ~sys_clk_ctr[reset_pow2]; end end // Reset in the video clock domain reg vid_rst_n; always @(negedge all_plls_locked or posedge vid_clk) if (~all_plls_locked) vid_rst_n <= 1'b0; else vid_rst_n <= rst_n; // HDMI video interface video video ( .rst_n ( vid_rst_n ), .vid_clk ( vid_clk ), .vid_hdmiclk ( vid_hdmiclk ), .hdmi_d ( hdmi_d ), .hdmi_clk ( hdmi_clk ), .hdmi_scl ( hdmi_scl ), .hdmi_hpd ( hdmi_hpd ) ); // // Internal CPU bus // wire cpu_mem_valid; wire cpu_mem_ready; wire cpu_mem_instr; wire [ 3:0] cpu_mem_wstrb; wire [31:0] cpu_mem_addr; wire [31:0] cpu_mem_wdata; reg [31:0] cpu_mem_rdata; wire cpu_la_read; wire cpu_la_write; wire [31:0] cpu_la_addr; wire [31:0] cpu_la_wdata; wire [ 3:0] cpu_la_wstrb; // cpu_mem_valid by address quadrant, using a bit of lookahead // decoding for speed. reg [3:0] mem_quad; always @(negedge rst_n or posedge sys_clk) if (~rst_n) mem_quad <= 4'b0; else if (cpu_mem_valid) mem_quad <= 1'b1 << cpu_mem_addr[31:30]; else mem_quad <= 1'b1 << cpu_la_addr[31:30]; wire [3:0] cpu_mem_quad = cpu_mem_valid ? mem_quad : 4'b0; // I/O device map from iodevs.conf wire iodev_mem_valid = cpu_mem_quad[3]; `include "iodevs.vh" // // SDRAM // localparam dram_port_count = 4; dram_bus sr_bus[1:dram_port_count] ( ); // ABC interface wire [24:0] abc_sr_addr; wire [ 7:0] abc_sr_rd; wire abc_sr_valid; wire abc_sr_ready; wire [ 7:0] abc_sr_wd; wire abc_sr_wstrb; dram_port #(8) abc_dram_port ( .bus ( sr_bus[1] ), .prio ( 2'd3 ), .addr ( abc_sr_addr ), .rd ( abc_sr_rd ), .valid ( abc_sr_valid ), .ready ( abc_sr_ready ), .wd ( abc_sr_wd ), .wstrb ( abc_sr_wstrb ) ); // CPU interface wire sdram_valid = cpu_mem_quad[1]; wire [31:0] sdram_mem_rdata; wire sdram_ready; reg sdram_ready_q; reg sdram_mem_ready; // // Retard sdram_ready by one sys_clk (multicycle path for the data, // see max80.sdc) // // Note that if the CPU leaves valid asserted the CPU cycle after // receiving ready, it is the beginning of another request. The // sdram core expects valid to be strobed, so deassert valid // to the sdram core while asserting ready to the CPU. // always @(posedge sys_clk) begin sdram_mem_ready <= sdram_ready & sdram_valid; end dram_port #(32) cpu_dram_port ( .bus ( sr_bus[4] ), .prio ( 2'd1 ), .addr ( cpu_mem_addr[24:0] ), .rd ( sdram_mem_rdata ), .valid ( sdram_valid & ~sdram_mem_ready ), .ready ( sdram_ready ), .wd ( cpu_mem_wdata ), .wstrb ( cpu_mem_wstrb ) ); // Romcopy interface wire [15:0] sdram_rom_wd; wire [24:1] sdram_rom_waddr; wire [ 1:0] sdram_rom_wrq; wire sdram_rom_wacc; sdram #(.port1_count(dram_port_count)) sdram ( .rst_n ( rst_n ), .clk ( sdram_clk ), // Internal memory clock .init_tmr ( sys_clk_stb[14] ), // > 100 μs (tP) after reset .rfsh_tmr ( sys_clk_stb[8] ), // < 3.9 μs (tREFI/2) .sr_cs_n ( sr_cs_n ), .sr_ras_n ( sr_ras_n ), .sr_cas_n ( sr_cas_n ), .sr_we_n ( sr_we_n ), .sr_dqm ( sr_dqm ), .sr_ba ( sr_ba ), .sr_a ( sr_a ), .sr_dq ( sr_dq ), .port1 ( sr_bus ), .a2 ( sdram_rom_waddr ), .wd2 ( sdram_rom_wd ), .wrq2 ( sdram_rom_wrq ), .wacc2 ( sdram_rom_wacc ) ); // // ABC-bus interface // wire abc_clk_s; // abc_clk synchronous to sys_clk abcbus #(.mosfet_installed(x_mosfet)) abcbus ( .rst_n ( rst_n ), .sys_clk ( sys_clk ), .sdram_clk ( sdram_clk ), .stb_1mhz ( sys_clk_stb[6] ), .abc_valid ( iodev_valid_abc ), .map_valid ( iodev_valid_abcmemmap ), .cpu_addr ( cpu_mem_addr ), .cpu_wdata ( cpu_mem_wdata ), .cpu_wstrb ( cpu_mem_wstrb ), .cpu_rdata ( iodev_rdata_abc ), .cpu_rdata_map ( iodev_rdata_abcmemmap ), .irq ( iodev_irq_abc ), .abc_clk ( abc_clk ), .abc_clk_s ( abc_clk_s ), .abc_a ( abc_a ), .abc_d ( abc_d ), .abc_d_oe ( abc_d_oe ), .abc_rst_n ( abc_rst_n ), .abc_cs_n ( abc_cs_n ), .abc_out_n ( abc_out_n ), .abc_inp_n ( abc_inp_n ), .abc_xmemfl_n ( abc_xmemfl_n ), .abc_xmemw800_n ( abc_xmemw800_n ), .abc_xmemw80_n ( abc_xmemw80_n ), .abc_xinpstb_n ( abc_xinpstb_n ), .abc_xoutpstb_n ( abc_xoutpstb_n ), .abc_rdy_x ( abc_rdy_x ), .abc_resin_x ( abc_resin_x ), .abc_int80_x ( abc_int80_x ), .abc_int800_x ( abc_int800_x ), .abc_nmi_x ( abc_nmi_x ), .abc_xm_x ( abc_xm_x ), .abc_host ( abc_host ), .exth_ha ( exth_ha ), .exth_hb ( exth_hb ), .exth_hc ( exth_hc ), .exth_hd ( exth_hd ), .exth_he ( exth_he ), .exth_hf ( exth_hf ), .exth_hg ( exth_hg ), .exth_hh ( exth_hh ), .sdram_addr ( abc_sr_addr ), .sdram_rd ( abc_sr_rd ), .sdram_valid ( abc_sr_valid ), .sdram_ready ( abc_sr_ready ), .sdram_wd ( abc_sr_wd ), .sdram_wstrb ( abc_sr_wstrb ) ); // Embedded RISC-V CPU // Edge-triggered IRQs. picorv32 latches interrupts // but doesn't edge detect for a slow signal, so do it // here instead and use level triggered signalling to the // CPU. This also allows using an explicit EOI instead of // using EOI-on-INTACK. // // sys_irq defined in iodevs.vh reg [31:0] sys_irq_q; reg [31:0] cpu_irq; wire [31:0] cpu_eoi = {32{sysreg[4]}} & {{8{cpu_mem_wstrb[3]}}, {8{cpu_mem_wstrb[2]}}, {8{cpu_mem_wstrb[1]}}, {8{cpu_mem_wstrb[0]}}} & cpu_mem_wdata; // Reading the register shows the current set of pending interrupts. assign sysreg_rdata[4] = cpu_irq; // CPU permanently hung? wire cpu_trap; // Request to halt the CPU on the next instruction boundary wire cpu_halt; always @(negedge rst_n or posedge sys_clk) if (~rst_n) begin sys_irq_q <= 32'b0; cpu_irq <= 32'b0; end else begin sys_irq_q <= sys_irq & irq_edge_mask; cpu_irq <= (sys_irq & ~sys_irq_q) | (cpu_irq & irq_edge_mask & ~cpu_eoi); end picorv32 #( .ENABLE_COUNTERS ( 1 ), .ENABLE_COUNTERS64 ( 1 ), .ENABLE_REGS_16_31 ( 1 ), .ENABLE_REGS_DUALPORT ( 1 ), .LATCHED_MEM_RDATA ( 0 ), .BARREL_SHIFTER ( 1 ), .TWO_CYCLE_COMPARE ( 0 ), .TWO_CYCLE_ALU ( 0 ), .COMPRESSED_ISA ( 1 ), .CATCH_MISALIGN ( 1 ), .CATCH_ILLINSN ( 1 ), .ENABLE_FAST_MUL ( 1 ), .ENABLE_DIV ( 1 ), .ENABLE_IRQ ( 1 ), .ENABLE_IRQ_QREGS ( 1 ), .ENABLE_IRQ_TIMER ( 1 ), .MASKED_IRQ ( irq_masked ), .LATCHED_IRQ ( 32'h0000_0007 ), .REGS_INIT_ZERO ( 1 ), .STACKADDR ( 1'b1 << SRAM_BITS ), .USER_CONTEXTS ( 7 ) ) cpu ( .clk ( sys_clk ), .resetn ( rst_n ), .halt ( cpu_halt ), .trap ( cpu_trap ), .progaddr_reset ( _PC_RESET ), .progaddr_irq ( _PC_IRQ ), .mem_instr ( cpu_mem_instr ), .mem_ready ( cpu_mem_ready ), .mem_valid ( cpu_mem_valid ), .mem_wstrb ( cpu_mem_wstrb ), .mem_addr ( cpu_mem_addr ), .mem_wdata ( cpu_mem_wdata ), .mem_rdata ( cpu_mem_rdata ), .mem_la_read ( cpu_la_read ), .mem_la_write ( cpu_la_write ), .mem_la_wdata ( cpu_la_wdata ), .mem_la_addr ( cpu_la_addr ), .mem_la_wstrb ( cpu_la_wstrb ), .irq ( cpu_irq ), .eoi ( ) ); // Add a mandatory wait state to iodevs to reduce the size // of the CPU memory input MUX (it hurts timing on memory // accesses...) reg iodev_mem_ready; assign cpu_mem_ready = (cpu_mem_quad[0] & 1'b1) | (cpu_mem_quad[1] & sdram_mem_ready) | (cpu_mem_quad[2] & 1'b1) | (cpu_mem_quad[3] & iodev_mem_ready); // // Fast memory. This runs on the SDRAM clock, i.e. 2x the speed // of the CPU. The .bits parameter gives the number of dwords // as a power of 2, i.e. 11 = 2^11 * 4 = 8K. // wire [31:0] fast_mem_rdata; wire [SRAM_BITS-1:2] vjtag_sram_addr; wire vjtag_sram_read; wire vjtag_sram_write; wire [31:0] vjtag_sram_rdata; wire [31:0] vjtag_sram_wdata; fast_mem #(.words_lg2(SRAM_BITS-2), .data_file("mif/sram.mif")) fast_mem( .rst_n ( rst_n ), .clk ( sys_clk ), .read0 ( 1'b1 ), // cpu_la_read & cpu_la_addr[31:30] == 2'b00 .write0 ( cpu_la_write & cpu_la_addr[31:30] == 2'b00 ), .wstrb0 ( cpu_la_wstrb ), .addr0 ( cpu_la_addr[SRAM_BITS-1:2] ), .wdata0 ( cpu_la_wdata ), .rdata0 ( fast_mem_rdata ), .read1 ( 1'b1 ), // vjtag_sram_read .write1 ( vjtag_sram_write ), .wstrb1 ( 4'b1111 ), .addr1 ( vjtag_sram_addr ), .wdata1 ( vjtag_sram_wdata ), .rdata1 ( vjtag_sram_rdata ) ); // Register I/O data to reduce the size of the read data MUX reg [31:0] iodev_rdata_q; // Read data MUX always_comb case ( cpu_mem_quad ) 4'b0001: cpu_mem_rdata = fast_mem_rdata; 4'b0010: cpu_mem_rdata = sdram_mem_rdata; 4'b1000: cpu_mem_rdata = iodev_rdata_q; default: cpu_mem_rdata = 32'hxxxx_xxxx; endcase // Miscellaneous system control/status registers wire [ 4:0] sysreg_subreg = cpu_mem_addr[6:2]; wire [31:0] sysreg = iodev_valid_sys << sysreg_subreg; tri1 [31:0] sysreg_rdata[0:31]; assign iodev_rdata_sys = sysreg_rdata[sysreg_subreg]; // // Board identification // // Magic number: "MAX8" // Board revision: 1.0/2.0 // Board rework flags: // [7:0] - reserved // wire rtc_32khz_rework = 1'b1; reg board_id_q; always @(posedge sys_clk) board_id_q <= board_id; wire [ 7:0] max80_fpga = fpga_ver; wire [ 7:0] max80_major = ~board_id_q ? 8'd2 : 8'd1; wire [ 7:0] max80_minor = 8'd0; wire [ 7:0] max80_fixes = 8'b0; assign sysreg_rdata[0] = SYS_MAGIC_MAX80; assign sysreg_rdata[1] = { max80_fpga, max80_major, max80_minor, max80_fixes }; // System reset wire usb_rxd_break_rst; // Reset due to USB serial port BREAK wire tty_rxd_break_rst; // Reset due to TTY serial port BREAK wire vjtag_reset_cmd; // Reset due to virtual JTAG request // Reset control. Note that CPU reset command 0 is a noop. wire [3:0] cpu_reset_io_cmd = (sysreg[3] & cpu_mem_wstrb[0]) << cpu_mem_wdata[1:0]; // // Soft system reset: FPGA not reloaded, PLLs not reset, // USB and console are not reset // // Triggered by: // - CPU reset command 1 // - CPU entering TRAP state (irrecoverable error) // - BREAK received on console // - VJTAG request // assign cpu_reset_cmd[1] = cpu_reset_io_cmd[1] | cpu_trap; assign aux_reset_cmd[1] = usb_rxd_break_rst | tty_rxd_break_rst | vjtag_reset_cmd; // // Hard system reset: FPGA not reloaded, PLLs reset, all hw units reset // assign cpu_reset_cmd[2] = cpu_reset_io_cmd[2]; assign aux_reset_cmd[2] = 1'b0; // // FPGA reload reset (not implemented yet) // assign cpu_reset_cmd[3] = cpu_reset_io_cmd[3]; assign aux_reset_cmd[3] = 1'b0; // LED indication from the CPU reg [2:0] led_q; always @(negedge rst_n or posedge sys_clk) if (~rst_n) led_q <= 3'b000; else if ( sysreg[2] & cpu_mem_wstrb[0] ) led_q <= cpu_mem_wdata[2:0]; assign led = led_q; assign sysreg_rdata[2] = { 29'b0, led_q }; // Random number generator wire rtc_clk_s; rng #(.nclocks(2), .width(32)) rng ( .rst_n ( rst_n ), .sys_clk ( sys_clk ), .read_stb ( iodev_valid_random ), .latch_stb ( sys_clk_stb[16] ), .ready ( iodev_irq_random ), .q ( iodev_rdata_random ), .clocks ( { rtc_clk_s, abc_clk_s } ), .rngio ( rngio ) ); // // Serial ROM (also configuration ROM.) Fast hardwired data download // unit to SDRAM. // wire rom_done; reg rom_done_q; spirom ddu ( .rst_n ( rst_n ), .rom_clk ( flash_clk ), .ram_clk ( sdram_clk ), .sys_clk ( sys_clk ), .spi_sck ( flash_sck ), .spi_io ( flash_io ), .spi_cs_n ( flash_cs_n ), .wd ( sdram_rom_wd ), .waddr ( sdram_rom_waddr ), .wrq ( sdram_rom_wrq ), .wacc ( sdram_rom_wacc ), .cpu_rdata ( iodev_rdata_romcopy ), .cpu_wdata ( cpu_mem_wdata ), .cpu_valid ( iodev_valid_romcopy ), .cpu_wstrb ( cpu_mem_wstrb ), .cpu_addr ( cpu_mem_addr[4:2] ), .irq ( iodev_irq_romcopy ) ); // // Serial port. Direct to the CP2102N for v1 boards // boards or to GPIO for v2 boards. // wire tty_data_out; // Output data wire tty_data_in; // Input data wire tty_cts_out; // Assert CTS# externally wire tty_rts_in; // RTS# received from outside wire tty_dtr_in; // DTR# received from outside assign tty_data_in = tty_txd; assign tty_rxd = tty_data_out; assign tty_rts_in = ~tty_rts; assign tty_dtr_in = ~tty_dtr; assign tty_cts = ~tty_cts_out; assign tty_cts_out = 1'b1; // Always assert CTS# for now // The physical tty now just snoops USB ACM channel 0; as such it does // not respond to any write requests nor issue any irqs wire serial_tx_full; wire serial_rx_break; serial #(.ENABLE_RX_DATA (1'b0), .ENABLE_RX_BREAK (1'b1), .ENABLE_TX_DATA (1'b1), .ENABLE_TX_BREAK (1'b0), .BAUDRATE_SETTABLE (1'b0), .BAUDRATE (921600), .TTY_CLK (84000000)) ( .rst_n ( hard_rst_n ), .clk ( sys_clk ), // Snoops USB TTY channel 0 .tx_wstrb ( iodev_valid_tty & cpu_mem_addr[6:2] == 5'b00000 & cpu_mem_wstrb[0] ), .tx_data ( cpu_mem_wdata[7:0] ), .tx_flush ( 1'b0 ), .rx_flush ( 1'b0 ), .tty_rx ( tty_data_in ), .tty_tx ( tty_data_out ), .tx_full ( serial_tx_full ), .rx_break ( tty_rxd_break_rst ) ); // If DTR# is asserted, block on full serial Tx FIFO; this allows // us to not lose debugging messages. assign iodev_wait_n_tty = ~(serial_tx_full & tty_dtr_in); max80_usb #( .channels( TTY_CHANNELS ) ) usb ( .hard_rst_n ( hard_rst_n ), .clock48 ( usb_clk ), .rst_n ( rst_n ), .sys_clk ( sys_clk ), .cpu_valid_usbdesc ( iodev_valid_usbdesc ), .cpu_valid_cdc ( iodev_valid_tty ), .cpu_addr ( cpu_mem_addr ), .cpu_rdata_usbdesc ( iodev_rdata_usbdesc ), .cpu_rdata_cdc ( iodev_rdata_tty ), .cpu_wdata ( cpu_mem_wdata ), .cpu_wstrb ( cpu_mem_wstrb ), .irq ( iodev_irq_tty ), .tty_rxd_break ( usb_rxd_break_rst ), .usb_dp ( usb_dp ), .usb_dn ( usb_dn ), .usb_pu ( usb_pu ), .usb_rx ( usb_rx ), .usb_rx_ok ( usb_rx_ok ) ); // SD card sdcard #( .with_irq_mask ( 8'b0000_0001 ) ) sdcard ( .rst_n ( rst_n ), .clk ( sys_clk ), .sd_cs_n ( sd_cs_n ), .sd_di ( sd_di ), .sd_sclk ( sd_clk ), .sd_do ( sd_do ), .sd_cd_n ( sd_cd_n ), .sd_irq_n ( 1'b1 ), .wdata ( cpu_mem_wdata ), .rdata ( iodev_rdata_sdcard ), .valid ( iodev_valid_sdcard ), .wstrb ( cpu_mem_wstrb ), .addr ( cpu_mem_addr[6:2] ), .wait_n ( iodev_wait_n_sdcard ), .irq ( iodev_irq_sdcard ) ); // // System local clock (not an RTC per se, but settable from one); // also provides a periodic interrupt, currently set to 32 Hz. // // The RTC 32.768 kHz output is open drain, so use the negative // edge for clocking. // wire clk_32kHz = ~rtc_32khz; // Inverted wire [15:0] rtc_ctr; sysclock #(.PERIODIC_HZ_LG2 ( TIMER_SHIFT )) sysclock ( .rst_n ( rst_n ), .sys_clk ( sys_clk ), .rtc_clk ( clk_32kHz ), .rtc_clk_s ( rtc_clk_s ), .wdata ( cpu_mem_wdata ), .rdata ( iodev_rdata_sysclock ), .valid ( iodev_valid_sysclock ), .wstrb ( cpu_mem_wstrb ), .addr ( cpu_mem_addr[2] ), .periodic ( iodev_irq_sysclock ), .rtc_ctr ( rtc_ctr ) ); // ESP32 assign spi_cs_flash_n = 1'bz; esp esp ( .rst_n ( rst_n ), .sys_clk ( sys_clk ), .sdram_clk ( sdram_clk ), .cpu_valid ( iodev_valid_esp ), .cpu_addr ( cpu_mem_addr[6:2] ), .cpu_wstrb ( cpu_mem_wstrb ), .cpu_wdata ( cpu_mem_wdata ), .cpu_rdata ( iodev_rdata_esp ), .irq ( iodev_irq_esp ), .esp_int ( esp_int ), .spi_clk ( spi_clk ), .spi_io ( spi_io ), .spi_cs_n ( spi_cs_esp_n ), .dram ( sr_bus[2].dstr ), .rtc_ctr ( rtc_ctr ) ); // // I2C bus (RTC and to connector) // i2c i2c ( .rst_n ( rst_n ), .clk ( sys_clk ), .valid ( iodev_valid_i2c ), .addr ( cpu_mem_addr[3:2] ), .wdata ( cpu_mem_wdata ), .wstrb ( cpu_mem_wstrb ), .rdata ( iodev_rdata_i2c ), .irq ( iodev_irq_i2c ), .i2c_scl ( i2c_scl ), .i2c_sda ( i2c_sda ) ); // Virtual JTAG interface wire vjtag_cpu_halt; vjtag_max80 #(.sdram_base_addr(SDRAM_ADDR), .sdram_bits(SDRAM_BITS), .sram_bits(SRAM_BITS)) vjtag ( .rst_n ( rst_n ), .sys_clk ( sys_clk ), .reset_cmd ( vjtag_reset_cmd ), .sdram ( sr_bus[3].dstr ), .cpu_valid ( iodev_valid_vjtag ), .cpu_addr ( cpu_mem_addr[6:2] ), .cpu_wdata ( cpu_mem_wdata ), .cpu_wstrb ( cpu_mem_wstrb ), .cpu_rdata ( iodev_rdata_vjtag ), .cpu_irq ( iodev_irq_vjtag ), .cpu_halt ( vjtag_cpu_halt ), .sram_addr ( vjtag_sram_addr ), .sram_rdata ( vjtag_sram_rdata ), .sram_wdata ( vjtag_sram_wdata ), .sram_read ( vjtag_sram_read ), .sram_write ( vjtag_sram_write ) ); assign cpu_halt = vjtag_cpu_halt; // // Registering of I/O data and handling of iodev_mem_ready // always @(posedge sys_clk) iodev_rdata_q <= iodev_rdata; always @(negedge rst_n or posedge sys_clk) if (~rst_n) iodev_mem_ready <= 1'b0; else iodev_mem_ready <= iodev_wait_n & cpu_mem_valid; endmodule